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Diffstat (limited to 'kernel/bpf/verifier.c')
-rw-r--r--kernel/bpf/verifier.c1531
1 files changed, 1414 insertions, 117 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 648a549c41ae..4e7f1d085e53 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -451,10 +451,24 @@ static bool reg_type_not_null(enum bpf_reg_type type)
type == PTR_TO_SOCK_COMMON;
}
+static struct btf_record *reg_btf_record(const struct bpf_reg_state *reg)
+{
+ struct btf_record *rec = NULL;
+ struct btf_struct_meta *meta;
+
+ if (reg->type == PTR_TO_MAP_VALUE) {
+ rec = reg->map_ptr->record;
+ } else if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC)) {
+ meta = btf_find_struct_meta(reg->btf, reg->btf_id);
+ if (meta)
+ rec = meta->record;
+ }
+ return rec;
+}
+
static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
{
- return reg->type == PTR_TO_MAP_VALUE &&
- btf_record_has_field(reg->map_ptr->record, BPF_SPIN_LOCK);
+ return btf_record_has_field(reg_btf_record(reg), BPF_SPIN_LOCK);
}
static bool type_is_rdonly_mem(u32 type)
@@ -513,6 +527,14 @@ static bool is_callback_calling_function(enum bpf_func_id func_id)
func_id == BPF_FUNC_user_ringbuf_drain;
}
+static bool is_storage_get_function(enum bpf_func_id func_id)
+{
+ return func_id == BPF_FUNC_sk_storage_get ||
+ func_id == BPF_FUNC_inode_storage_get ||
+ func_id == BPF_FUNC_task_storage_get ||
+ func_id == BPF_FUNC_cgrp_storage_get;
+}
+
static bool helper_multiple_ref_obj_use(enum bpf_func_id func_id,
const struct bpf_map *map)
{
@@ -543,7 +565,7 @@ static bool is_cmpxchg_insn(const struct bpf_insn *insn)
static const char *reg_type_str(struct bpf_verifier_env *env,
enum bpf_reg_type type)
{
- char postfix[16] = {0}, prefix[32] = {0};
+ char postfix[16] = {0}, prefix[64] = {0};
static const char * const str[] = {
[NOT_INIT] = "?",
[SCALAR_VALUE] = "scalar",
@@ -575,16 +597,15 @@ static const char *reg_type_str(struct bpf_verifier_env *env,
strncpy(postfix, "_or_null", 16);
}
- if (type & MEM_RDONLY)
- strncpy(prefix, "rdonly_", 32);
- if (type & MEM_ALLOC)
- strncpy(prefix, "alloc_", 32);
- if (type & MEM_USER)
- strncpy(prefix, "user_", 32);
- if (type & MEM_PERCPU)
- strncpy(prefix, "percpu_", 32);
- if (type & PTR_UNTRUSTED)
- strncpy(prefix, "untrusted_", 32);
+ snprintf(prefix, sizeof(prefix), "%s%s%s%s%s%s%s",
+ type & MEM_RDONLY ? "rdonly_" : "",
+ type & MEM_RINGBUF ? "ringbuf_" : "",
+ type & MEM_USER ? "user_" : "",
+ type & MEM_PERCPU ? "percpu_" : "",
+ type & MEM_RCU ? "rcu_" : "",
+ type & PTR_UNTRUSTED ? "untrusted_" : "",
+ type & PTR_TRUSTED ? "trusted_" : ""
+ );
snprintf(env->type_str_buf, TYPE_STR_BUF_LEN, "%s%s%s",
prefix, str[base_type(type)], postfix);
@@ -1010,9 +1031,9 @@ static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t
if (unlikely(check_mul_overflow(n, size, &bytes)))
return NULL;
- if (ksize(dst) < bytes) {
+ if (ksize(dst) < ksize(src)) {
kfree(dst);
- dst = kmalloc_track_caller(bytes, flags);
+ dst = kmalloc_track_caller(kmalloc_size_roundup(bytes), flags);
if (!dst)
return NULL;
}
@@ -1029,12 +1050,14 @@ out:
*/
static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size)
{
+ size_t alloc_size;
void *new_arr;
if (!new_n || old_n == new_n)
goto out;
- new_arr = krealloc_array(arr, new_n, size, GFP_KERNEL);
+ alloc_size = kmalloc_size_roundup(size_mul(new_n, size));
+ new_arr = krealloc(arr, alloc_size, GFP_KERNEL);
if (!new_arr) {
kfree(arr);
return NULL;
@@ -1206,8 +1229,10 @@ static int copy_verifier_state(struct bpf_verifier_state *dst_state,
dst_state->frame[i] = NULL;
}
dst_state->speculative = src->speculative;
+ dst_state->active_rcu_lock = src->active_rcu_lock;
dst_state->curframe = src->curframe;
- dst_state->active_spin_lock = src->active_spin_lock;
+ dst_state->active_lock.ptr = src->active_lock.ptr;
+ dst_state->active_lock.id = src->active_lock.id;
dst_state->branches = src->branches;
dst_state->parent = src->parent;
dst_state->first_insn_idx = src->first_insn_idx;
@@ -2506,9 +2531,11 @@ static int push_jmp_history(struct bpf_verifier_env *env,
{
u32 cnt = cur->jmp_history_cnt;
struct bpf_idx_pair *p;
+ size_t alloc_size;
cnt++;
- p = krealloc(cur->jmp_history, cnt * sizeof(*p), GFP_USER);
+ alloc_size = kmalloc_size_roundup(size_mul(cnt, sizeof(*p)));
+ p = krealloc(cur->jmp_history, alloc_size, GFP_USER);
if (!p)
return -ENOMEM;
p[cnt - 1].idx = env->insn_idx;
@@ -3844,7 +3871,7 @@ static int map_kptr_match_type(struct bpf_verifier_env *env,
struct bpf_reg_state *reg, u32 regno)
{
const char *targ_name = kernel_type_name(kptr_field->kptr.btf, kptr_field->kptr.btf_id);
- int perm_flags = PTR_MAYBE_NULL;
+ int perm_flags = PTR_MAYBE_NULL | PTR_TRUSTED;
const char *reg_name = "";
/* Only unreferenced case accepts untrusted pointers */
@@ -4241,6 +4268,25 @@ static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno)
return reg->type == PTR_TO_FLOW_KEYS;
}
+static bool is_trusted_reg(const struct bpf_reg_state *reg)
+{
+ /* A referenced register is always trusted. */
+ if (reg->ref_obj_id)
+ return true;
+
+ /* If a register is not referenced, it is trusted if it has the
+ * MEM_ALLOC, MEM_RCU or PTR_TRUSTED type modifiers, and no others. Some of the
+ * other type modifiers may be safe, but we elect to take an opt-in
+ * approach here as some (e.g. PTR_UNTRUSTED and PTR_MAYBE_NULL) are
+ * not.
+ *
+ * Eventually, we should make PTR_TRUSTED the single source of truth
+ * for whether a register is trusted.
+ */
+ return type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS &&
+ !bpf_type_has_unsafe_modifiers(reg->type);
+}
+
static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
const struct bpf_reg_state *reg,
int off, int size, bool strict)
@@ -4687,17 +4733,28 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
return -EACCES;
}
- if (env->ops->btf_struct_access) {
- ret = env->ops->btf_struct_access(&env->log, reg->btf, t,
- off, size, atype, &btf_id, &flag);
+ if (env->ops->btf_struct_access && !type_is_alloc(reg->type)) {
+ if (!btf_is_kernel(reg->btf)) {
+ verbose(env, "verifier internal error: reg->btf must be kernel btf\n");
+ return -EFAULT;
+ }
+ ret = env->ops->btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag);
} else {
- if (atype != BPF_READ) {
+ /* Writes are permitted with default btf_struct_access for
+ * program allocated objects (which always have ref_obj_id > 0),
+ * but not for untrusted PTR_TO_BTF_ID | MEM_ALLOC.
+ */
+ if (atype != BPF_READ && reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
verbose(env, "only read is supported\n");
return -EACCES;
}
- ret = btf_struct_access(&env->log, reg->btf, t, off, size,
- atype, &btf_id, &flag);
+ if (type_is_alloc(reg->type) && !reg->ref_obj_id) {
+ verbose(env, "verifier internal error: ref_obj_id for allocated object must be non-zero\n");
+ return -EFAULT;
+ }
+
+ ret = btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag);
}
if (ret < 0)
@@ -4709,6 +4766,28 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
if (type_flag(reg->type) & PTR_UNTRUSTED)
flag |= PTR_UNTRUSTED;
+ /* By default any pointer obtained from walking a trusted pointer is
+ * no longer trusted except the rcu case below.
+ */
+ flag &= ~PTR_TRUSTED;
+
+ if (flag & MEM_RCU) {
+ /* Mark value register as MEM_RCU only if it is protected by
+ * bpf_rcu_read_lock() and the ptr reg is trusted. MEM_RCU
+ * itself can already indicate trustedness inside the rcu
+ * read lock region. Also mark it as PTR_TRUSTED.
+ */
+ if (!env->cur_state->active_rcu_lock || !is_trusted_reg(reg))
+ flag &= ~MEM_RCU;
+ else
+ flag |= PTR_TRUSTED;
+ } else if (reg->type & MEM_RCU) {
+ /* ptr (reg) is marked as MEM_RCU, but the struct field is not tagged
+ * with __rcu. Mark the flag as PTR_UNTRUSTED conservatively.
+ */
+ flag |= PTR_UNTRUSTED;
+ }
+
if (atype == BPF_READ && value_regno >= 0)
mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag);
@@ -4723,6 +4802,7 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env,
{
struct bpf_reg_state *reg = regs + regno;
struct bpf_map *map = reg->map_ptr;
+ struct bpf_reg_state map_reg;
enum bpf_type_flag flag = 0;
const struct btf_type *t;
const char *tname;
@@ -4761,7 +4841,10 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env,
return -EACCES;
}
- ret = btf_struct_access(&env->log, btf_vmlinux, t, off, size, atype, &btf_id, &flag);
+ /* Simulate access to a PTR_TO_BTF_ID */
+ memset(&map_reg, 0, sizeof(map_reg));
+ mark_btf_ld_reg(env, &map_reg, 0, PTR_TO_BTF_ID, btf_vmlinux, *map->ops->map_btf_id, 0);
+ ret = btf_struct_access(&env->log, &map_reg, off, size, atype, &btf_id, &flag);
if (ret < 0)
return ret;
@@ -5520,8 +5603,8 @@ int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
return err;
}
-int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
- u32 regno)
+static int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+ u32 regno)
{
struct bpf_reg_state *mem_reg = &cur_regs(env)[regno - 1];
bool may_be_null = type_may_be_null(mem_reg->type);
@@ -5549,23 +5632,26 @@ int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state
}
/* Implementation details:
- * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL
+ * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL.
+ * bpf_obj_new returns PTR_TO_BTF_ID | MEM_ALLOC | PTR_MAYBE_NULL.
* Two bpf_map_lookups (even with the same key) will have different reg->id.
- * For traditional PTR_TO_MAP_VALUE the verifier clears reg->id after
- * value_or_null->value transition, since the verifier only cares about
- * the range of access to valid map value pointer and doesn't care about actual
- * address of the map element.
+ * Two separate bpf_obj_new will also have different reg->id.
+ * For traditional PTR_TO_MAP_VALUE or PTR_TO_BTF_ID | MEM_ALLOC, the verifier
+ * clears reg->id after value_or_null->value transition, since the verifier only
+ * cares about the range of access to valid map value pointer and doesn't care
+ * about actual address of the map element.
* For maps with 'struct bpf_spin_lock' inside map value the verifier keeps
* reg->id > 0 after value_or_null->value transition. By doing so
* two bpf_map_lookups will be considered two different pointers that
- * point to different bpf_spin_locks.
+ * point to different bpf_spin_locks. Likewise for pointers to allocated objects
+ * returned from bpf_obj_new.
* The verifier allows taking only one bpf_spin_lock at a time to avoid
* dead-locks.
* Since only one bpf_spin_lock is allowed the checks are simpler than
* reg_is_refcounted() logic. The verifier needs to remember only
* one spin_lock instead of array of acquired_refs.
- * cur_state->active_spin_lock remembers which map value element got locked
- * and clears it after bpf_spin_unlock.
+ * cur_state->active_lock remembers which map value element or allocated
+ * object got locked and clears it after bpf_spin_unlock.
*/
static int process_spin_lock(struct bpf_verifier_env *env, int regno,
bool is_lock)
@@ -5573,8 +5659,10 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno,
struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
struct bpf_verifier_state *cur = env->cur_state;
bool is_const = tnum_is_const(reg->var_off);
- struct bpf_map *map = reg->map_ptr;
u64 val = reg->var_off.value;
+ struct bpf_map *map = NULL;
+ struct btf *btf = NULL;
+ struct btf_record *rec;
if (!is_const) {
verbose(env,
@@ -5582,38 +5670,78 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno,
regno);
return -EINVAL;
}
- if (!map->btf) {
- verbose(env,
- "map '%s' has to have BTF in order to use bpf_spin_lock\n",
- map->name);
- return -EINVAL;
+ if (reg->type == PTR_TO_MAP_VALUE) {
+ map = reg->map_ptr;
+ if (!map->btf) {
+ verbose(env,
+ "map '%s' has to have BTF in order to use bpf_spin_lock\n",
+ map->name);
+ return -EINVAL;
+ }
+ } else {
+ btf = reg->btf;
}
- if (!btf_record_has_field(map->record, BPF_SPIN_LOCK)) {
- verbose(env, "map '%s' has no valid bpf_spin_lock\n", map->name);
+
+ rec = reg_btf_record(reg);
+ if (!btf_record_has_field(rec, BPF_SPIN_LOCK)) {
+ verbose(env, "%s '%s' has no valid bpf_spin_lock\n", map ? "map" : "local",
+ map ? map->name : "kptr");
return -EINVAL;
}
- if (map->record->spin_lock_off != val + reg->off) {
+ if (rec->spin_lock_off != val + reg->off) {
verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock' that is at %d\n",
- val + reg->off, map->record->spin_lock_off);
+ val + reg->off, rec->spin_lock_off);
return -EINVAL;
}
if (is_lock) {
- if (cur->active_spin_lock) {
+ if (cur->active_lock.ptr) {
verbose(env,
"Locking two bpf_spin_locks are not allowed\n");
return -EINVAL;
}
- cur->active_spin_lock = reg->id;
+ if (map)
+ cur->active_lock.ptr = map;
+ else
+ cur->active_lock.ptr = btf;
+ cur->active_lock.id = reg->id;
} else {
- if (!cur->active_spin_lock) {
+ struct bpf_func_state *fstate = cur_func(env);
+ void *ptr;
+ int i;
+
+ if (map)
+ ptr = map;
+ else
+ ptr = btf;
+
+ if (!cur->active_lock.ptr) {
verbose(env, "bpf_spin_unlock without taking a lock\n");
return -EINVAL;
}
- if (cur->active_spin_lock != reg->id) {
+ if (cur->active_lock.ptr != ptr ||
+ cur->active_lock.id != reg->id) {
verbose(env, "bpf_spin_unlock of different lock\n");
return -EINVAL;
}
- cur->active_spin_lock = 0;
+ cur->active_lock.ptr = NULL;
+ cur->active_lock.id = 0;
+
+ for (i = 0; i < fstate->acquired_refs; i++) {
+ int err;
+
+ /* Complain on error because this reference state cannot
+ * be freed before this point, as bpf_spin_lock critical
+ * section does not allow functions that release the
+ * allocated object immediately.
+ */
+ if (!fstate->refs[i].release_on_unlock)
+ continue;
+ err = release_reference(env, fstate->refs[i].id);
+ if (err) {
+ verbose(env, "failed to release release_on_unlock reference");
+ return err;
+ }
+ }
}
return 0;
}
@@ -5772,6 +5900,7 @@ static const struct bpf_reg_types btf_id_sock_common_types = {
PTR_TO_TCP_SOCK,
PTR_TO_XDP_SOCK,
PTR_TO_BTF_ID,
+ PTR_TO_BTF_ID | PTR_TRUSTED,
},
.btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
};
@@ -5785,7 +5914,7 @@ static const struct bpf_reg_types mem_types = {
PTR_TO_MAP_KEY,
PTR_TO_MAP_VALUE,
PTR_TO_MEM,
- PTR_TO_MEM | MEM_ALLOC,
+ PTR_TO_MEM | MEM_RINGBUF,
PTR_TO_BUF,
},
};
@@ -5800,14 +5929,31 @@ static const struct bpf_reg_types int_ptr_types = {
},
};
+static const struct bpf_reg_types spin_lock_types = {
+ .types = {
+ PTR_TO_MAP_VALUE,
+ PTR_TO_BTF_ID | MEM_ALLOC,
+ }
+};
+
static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } };
static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } };
static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } };
-static const struct bpf_reg_types alloc_mem_types = { .types = { PTR_TO_MEM | MEM_ALLOC } };
+static const struct bpf_reg_types ringbuf_mem_types = { .types = { PTR_TO_MEM | MEM_RINGBUF } };
static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } };
-static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } };
-static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } };
-static const struct bpf_reg_types percpu_btf_ptr_types = { .types = { PTR_TO_BTF_ID | MEM_PERCPU } };
+static const struct bpf_reg_types btf_ptr_types = {
+ .types = {
+ PTR_TO_BTF_ID,
+ PTR_TO_BTF_ID | PTR_TRUSTED,
+ PTR_TO_BTF_ID | MEM_RCU | PTR_TRUSTED,
+ },
+};
+static const struct bpf_reg_types percpu_btf_ptr_types = {
+ .types = {
+ PTR_TO_BTF_ID | MEM_PERCPU,
+ PTR_TO_BTF_ID | MEM_PERCPU | PTR_TRUSTED,
+ }
+};
static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } };
static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } };
static const struct bpf_reg_types const_str_ptr_types = { .types = { PTR_TO_MAP_VALUE } };
@@ -5836,7 +5982,7 @@ static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = {
[ARG_PTR_TO_BTF_ID] = &btf_ptr_types,
[ARG_PTR_TO_SPIN_LOCK] = &spin_lock_types,
[ARG_PTR_TO_MEM] = &mem_types,
- [ARG_PTR_TO_ALLOC_MEM] = &alloc_mem_types,
+ [ARG_PTR_TO_RINGBUF_MEM] = &ringbuf_mem_types,
[ARG_PTR_TO_INT] = &int_ptr_types,
[ARG_PTR_TO_LONG] = &int_ptr_types,
[ARG_PTR_TO_PERCPU_BTF_ID] = &percpu_btf_ptr_types,
@@ -5895,7 +6041,7 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
return -EACCES;
found:
- if (reg->type == PTR_TO_BTF_ID) {
+ if (reg->type == PTR_TO_BTF_ID || reg->type & PTR_TRUSTED) {
/* For bpf_sk_release, it needs to match against first member
* 'struct sock_common', hence make an exception for it. This
* allows bpf_sk_release to work for multiple socket types.
@@ -5931,6 +6077,11 @@ found:
return -EACCES;
}
}
+ } else if (type_is_alloc(reg->type)) {
+ if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock) {
+ verbose(env, "verifier internal error: unimplemented handling of MEM_ALLOC\n");
+ return -EFAULT;
+ }
}
return 0;
@@ -5957,20 +6108,24 @@ int check_func_arg_reg_off(struct bpf_verifier_env *env,
case PTR_TO_MAP_VALUE:
case PTR_TO_MEM:
case PTR_TO_MEM | MEM_RDONLY:
- case PTR_TO_MEM | MEM_ALLOC:
+ case PTR_TO_MEM | MEM_RINGBUF:
case PTR_TO_BUF:
case PTR_TO_BUF | MEM_RDONLY:
case SCALAR_VALUE:
/* Some of the argument types nevertheless require a
* zero register offset.
*/
- if (base_type(arg_type) != ARG_PTR_TO_ALLOC_MEM)
+ if (base_type(arg_type) != ARG_PTR_TO_RINGBUF_MEM)
return 0;
break;
/* All the rest must be rejected, except PTR_TO_BTF_ID which allows
* fixed offset.
*/
case PTR_TO_BTF_ID:
+ case PTR_TO_BTF_ID | MEM_ALLOC:
+ case PTR_TO_BTF_ID | PTR_TRUSTED:
+ case PTR_TO_BTF_ID | MEM_RCU | PTR_TRUSTED:
+ case PTR_TO_BTF_ID | MEM_ALLOC | PTR_TRUSTED:
/* When referenced PTR_TO_BTF_ID is passed to release function,
* it's fixed offset must be 0. In the other cases, fixed offset
* can be non-zero.
@@ -6046,7 +6201,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
goto skip_type_check;
/* arg_btf_id and arg_size are in a union. */
- if (base_type(arg_type) == ARG_PTR_TO_BTF_ID)
+ if (base_type(arg_type) == ARG_PTR_TO_BTF_ID ||
+ base_type(arg_type) == ARG_PTR_TO_SPIN_LOCK)
arg_btf_id = fn->arg_btf_id[arg];
err = check_reg_type(env, regno, arg_type, arg_btf_id, meta);
@@ -6664,9 +6820,10 @@ static bool check_btf_id_ok(const struct bpf_func_proto *fn)
int i;
for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) {
- if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID && !fn->arg_btf_id[i])
- return false;
-
+ if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID)
+ return !!fn->arg_btf_id[i];
+ if (base_type(fn->arg_type[i]) == ARG_PTR_TO_SPIN_LOCK)
+ return fn->arg_btf_id[i] == BPF_PTR_POISON;
if (base_type(fn->arg_type[i]) != ARG_PTR_TO_BTF_ID && fn->arg_btf_id[i] &&
/* arg_btf_id and arg_size are in a union. */
(base_type(fn->arg_type[i]) != ARG_PTR_TO_MEM ||
@@ -7413,6 +7570,11 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
return -EINVAL;
}
+ if (!env->prog->aux->sleepable && fn->might_sleep) {
+ verbose(env, "helper call might sleep in a non-sleepable prog\n");
+ return -EINVAL;
+ }
+
/* With LD_ABS/IND some JITs save/restore skb from r1. */
changes_data = bpf_helper_changes_pkt_data(fn->func);
if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) {
@@ -7431,6 +7593,17 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
return err;
}
+ if (env->cur_state->active_rcu_lock) {
+ if (fn->might_sleep) {
+ verbose(env, "sleepable helper %s#%d in rcu_read_lock region\n",
+ func_id_name(func_id), func_id);
+ return -EINVAL;
+ }
+
+ if (env->prog->aux->sleepable && is_storage_get_function(func_id))
+ env->insn_aux_data[insn_idx].storage_get_func_atomic = true;
+ }
+
meta.func_id = func_id;
/* check args */
for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
@@ -7634,7 +7807,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;
break;
- case RET_PTR_TO_ALLOC_MEM:
+ case RET_PTR_TO_MEM:
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
regs[BPF_REG_0].mem_size = meta.mem_size;
@@ -7797,19 +7970,921 @@ static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno,
}
}
+struct bpf_kfunc_call_arg_meta {
+ /* In parameters */
+ struct btf *btf;
+ u32 func_id;
+ u32 kfunc_flags;
+ const struct btf_type *func_proto;
+ const char *func_name;
+ /* Out parameters */
+ u32 ref_obj_id;
+ u8 release_regno;
+ bool r0_rdonly;
+ u32 ret_btf_id;
+ u64 r0_size;
+ struct {
+ u64 value;
+ bool found;
+ } arg_constant;
+ struct {
+ struct btf *btf;
+ u32 btf_id;
+ } arg_obj_drop;
+ struct {
+ struct btf_field *field;
+ } arg_list_head;
+};
+
+static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_ACQUIRE;
+}
+
+static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_RET_NULL;
+}
+
+static bool is_kfunc_release(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_RELEASE;
+}
+
+static bool is_kfunc_trusted_args(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_TRUSTED_ARGS;
+}
+
+static bool is_kfunc_sleepable(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_SLEEPABLE;
+}
+
+static bool is_kfunc_destructive(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->kfunc_flags & KF_DESTRUCTIVE;
+}
+
+static bool is_kfunc_arg_kptr_get(struct bpf_kfunc_call_arg_meta *meta, int arg)
+{
+ return arg == 0 && (meta->kfunc_flags & KF_KPTR_GET);
+}
+
+static bool __kfunc_param_match_suffix(const struct btf *btf,
+ const struct btf_param *arg,
+ const char *suffix)
+{
+ int suffix_len = strlen(suffix), len;
+ const char *param_name;
+
+ /* In the future, this can be ported to use BTF tagging */
+ param_name = btf_name_by_offset(btf, arg->name_off);
+ if (str_is_empty(param_name))
+ return false;
+ len = strlen(param_name);
+ if (len < suffix_len)
+ return false;
+ param_name += len - suffix_len;
+ return !strncmp(param_name, suffix, suffix_len);
+}
+
+static bool is_kfunc_arg_mem_size(const struct btf *btf,
+ const struct btf_param *arg,
+ const struct bpf_reg_state *reg)
+{
+ const struct btf_type *t;
+
+ t = btf_type_skip_modifiers(btf, arg->type, NULL);
+ if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
+ return false;
+
+ return __kfunc_param_match_suffix(btf, arg, "__sz");
+}
+
+static bool is_kfunc_arg_constant(const struct btf *btf, const struct btf_param *arg)
+{
+ return __kfunc_param_match_suffix(btf, arg, "__k");
+}
+
+static bool is_kfunc_arg_ignore(const struct btf *btf, const struct btf_param *arg)
+{
+ return __kfunc_param_match_suffix(btf, arg, "__ign");
+}
+
+static bool is_kfunc_arg_alloc_obj(const struct btf *btf, const struct btf_param *arg)
+{
+ return __kfunc_param_match_suffix(btf, arg, "__alloc");
+}
+
+static bool is_kfunc_arg_scalar_with_name(const struct btf *btf,
+ const struct btf_param *arg,
+ const char *name)
+{
+ int len, target_len = strlen(name);
+ const char *param_name;
+
+ param_name = btf_name_by_offset(btf, arg->name_off);
+ if (str_is_empty(param_name))
+ return false;
+ len = strlen(param_name);
+ if (len != target_len)
+ return false;
+ if (strcmp(param_name, name))
+ return false;
+
+ return true;
+}
+
+enum {
+ KF_ARG_DYNPTR_ID,
+ KF_ARG_LIST_HEAD_ID,
+ KF_ARG_LIST_NODE_ID,
+};
+
+BTF_ID_LIST(kf_arg_btf_ids)
+BTF_ID(struct, bpf_dynptr_kern)
+BTF_ID(struct, bpf_list_head)
+BTF_ID(struct, bpf_list_node)
+
+static bool __is_kfunc_ptr_arg_type(const struct btf *btf,
+ const struct btf_param *arg, int type)
+{
+ const struct btf_type *t;
+ u32 res_id;
+
+ t = btf_type_skip_modifiers(btf, arg->type, NULL);
+ if (!t)
+ return false;
+ if (!btf_type_is_ptr(t))
+ return false;
+ t = btf_type_skip_modifiers(btf, t->type, &res_id);
+ if (!t)
+ return false;
+ return btf_types_are_same(btf, res_id, btf_vmlinux, kf_arg_btf_ids[type]);
+}
+
+static bool is_kfunc_arg_dynptr(const struct btf *btf, const struct btf_param *arg)
+{
+ return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_DYNPTR_ID);
+}
+
+static bool is_kfunc_arg_list_head(const struct btf *btf, const struct btf_param *arg)
+{
+ return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_HEAD_ID);
+}
+
+static bool is_kfunc_arg_list_node(const struct btf *btf, const struct btf_param *arg)
+{
+ return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_NODE_ID);
+}
+
+/* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
+static bool __btf_type_is_scalar_struct(struct bpf_verifier_env *env,
+ const struct btf *btf,
+ const struct btf_type *t, int rec)
+{
+ const struct btf_type *member_type;
+ const struct btf_member *member;
+ u32 i;
+
+ if (!btf_type_is_struct(t))
+ return false;
+
+ for_each_member(i, t, member) {
+ const struct btf_array *array;
+
+ member_type = btf_type_skip_modifiers(btf, member->type, NULL);
+ if (btf_type_is_struct(member_type)) {
+ if (rec >= 3) {
+ verbose(env, "max struct nesting depth exceeded\n");
+ return false;
+ }
+ if (!__btf_type_is_scalar_struct(env, btf, member_type, rec + 1))
+ return false;
+ continue;
+ }
+ if (btf_type_is_array(member_type)) {
+ array = btf_array(member_type);
+ if (!array->nelems)
+ return false;
+ member_type = btf_type_skip_modifiers(btf, array->type, NULL);
+ if (!btf_type_is_scalar(member_type))
+ return false;
+ continue;
+ }
+ if (!btf_type_is_scalar(member_type))
+ return false;
+ }
+ return true;
+}
+
+
+static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
+#ifdef CONFIG_NET
+ [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
+ [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
+ [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
+#endif
+};
+
+enum kfunc_ptr_arg_type {
+ KF_ARG_PTR_TO_CTX,
+ KF_ARG_PTR_TO_ALLOC_BTF_ID, /* Allocated object */
+ KF_ARG_PTR_TO_KPTR, /* PTR_TO_KPTR but type specific */
+ KF_ARG_PTR_TO_DYNPTR,
+ KF_ARG_PTR_TO_LIST_HEAD,
+ KF_ARG_PTR_TO_LIST_NODE,
+ KF_ARG_PTR_TO_BTF_ID, /* Also covers reg2btf_ids conversions */
+ KF_ARG_PTR_TO_MEM,
+ KF_ARG_PTR_TO_MEM_SIZE, /* Size derived from next argument, skip it */
+};
+
+enum special_kfunc_type {
+ KF_bpf_obj_new_impl,
+ KF_bpf_obj_drop_impl,
+ KF_bpf_list_push_front,
+ KF_bpf_list_push_back,
+ KF_bpf_list_pop_front,
+ KF_bpf_list_pop_back,
+ KF_bpf_cast_to_kern_ctx,
+ KF_bpf_rdonly_cast,
+ KF_bpf_rcu_read_lock,
+ KF_bpf_rcu_read_unlock,
+};
+
+BTF_SET_START(special_kfunc_set)
+BTF_ID(func, bpf_obj_new_impl)
+BTF_ID(func, bpf_obj_drop_impl)
+BTF_ID(func, bpf_list_push_front)
+BTF_ID(func, bpf_list_push_back)
+BTF_ID(func, bpf_list_pop_front)
+BTF_ID(func, bpf_list_pop_back)
+BTF_ID(func, bpf_cast_to_kern_ctx)
+BTF_ID(func, bpf_rdonly_cast)
+BTF_SET_END(special_kfunc_set)
+
+BTF_ID_LIST(special_kfunc_list)
+BTF_ID(func, bpf_obj_new_impl)
+BTF_ID(func, bpf_obj_drop_impl)
+BTF_ID(func, bpf_list_push_front)
+BTF_ID(func, bpf_list_push_back)
+BTF_ID(func, bpf_list_pop_front)
+BTF_ID(func, bpf_list_pop_back)
+BTF_ID(func, bpf_cast_to_kern_ctx)
+BTF_ID(func, bpf_rdonly_cast)
+BTF_ID(func, bpf_rcu_read_lock)
+BTF_ID(func, bpf_rcu_read_unlock)
+
+static bool is_kfunc_bpf_rcu_read_lock(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_lock];
+}
+
+static bool is_kfunc_bpf_rcu_read_unlock(struct bpf_kfunc_call_arg_meta *meta)
+{
+ return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_unlock];
+}
+
+static enum kfunc_ptr_arg_type
+get_kfunc_ptr_arg_type(struct bpf_verifier_env *env,
+ struct bpf_kfunc_call_arg_meta *meta,
+ const struct btf_type *t, const struct btf_type *ref_t,
+ const char *ref_tname, const struct btf_param *args,
+ int argno, int nargs)
+{
+ u32 regno = argno + 1;
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_reg_state *reg = &regs[regno];
+ bool arg_mem_size = false;
+
+ if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx])
+ return KF_ARG_PTR_TO_CTX;
+
+ /* In this function, we verify the kfunc's BTF as per the argument type,
+ * leaving the rest of the verification with respect to the register
+ * type to our caller. When a set of conditions hold in the BTF type of
+ * arguments, we resolve it to a known kfunc_ptr_arg_type.
+ */
+ if (btf_get_prog_ctx_type(&env->log, meta->btf, t, resolve_prog_type(env->prog), argno))
+ return KF_ARG_PTR_TO_CTX;
+
+ if (is_kfunc_arg_alloc_obj(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_ALLOC_BTF_ID;
+
+ if (is_kfunc_arg_kptr_get(meta, argno)) {
+ if (!btf_type_is_ptr(ref_t)) {
+ verbose(env, "arg#0 BTF type must be a double pointer for kptr_get kfunc\n");
+ return -EINVAL;
+ }
+ ref_t = btf_type_by_id(meta->btf, ref_t->type);
+ ref_tname = btf_name_by_offset(meta->btf, ref_t->name_off);
+ if (!btf_type_is_struct(ref_t)) {
+ verbose(env, "kernel function %s args#0 pointer type %s %s is not supported\n",
+ meta->func_name, btf_type_str(ref_t), ref_tname);
+ return -EINVAL;
+ }
+ return KF_ARG_PTR_TO_KPTR;
+ }
+
+ if (is_kfunc_arg_dynptr(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_DYNPTR;
+
+ if (is_kfunc_arg_list_head(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_LIST_HEAD;
+
+ if (is_kfunc_arg_list_node(meta->btf, &args[argno]))
+ return KF_ARG_PTR_TO_LIST_NODE;
+
+ if ((base_type(reg->type) == PTR_TO_BTF_ID || reg2btf_ids[base_type(reg->type)])) {
+ if (!btf_type_is_struct(ref_t)) {
+ verbose(env, "kernel function %s args#%d pointer type %s %s is not supported\n",
+ meta->func_name, argno, btf_type_str(ref_t), ref_tname);
+ return -EINVAL;
+ }
+ return KF_ARG_PTR_TO_BTF_ID;
+ }
+
+ if (argno + 1 < nargs && is_kfunc_arg_mem_size(meta->btf, &args[argno + 1], &regs[regno + 1]))
+ arg_mem_size = true;
+
+ /* This is the catch all argument type of register types supported by
+ * check_helper_mem_access. However, we only allow when argument type is
+ * pointer to scalar, or struct composed (recursively) of scalars. When
+ * arg_mem_size is true, the pointer can be void *.
+ */
+ if (!btf_type_is_scalar(ref_t) && !__btf_type_is_scalar_struct(env, meta->btf, ref_t, 0) &&
+ (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
+ verbose(env, "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
+ argno, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
+ return -EINVAL;
+ }
+ return arg_mem_size ? KF_ARG_PTR_TO_MEM_SIZE : KF_ARG_PTR_TO_MEM;
+}
+
+static int process_kf_arg_ptr_to_btf_id(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ const struct btf_type *ref_t,
+ const char *ref_tname, u32 ref_id,
+ struct bpf_kfunc_call_arg_meta *meta,
+ int argno)
+{
+ const struct btf_type *reg_ref_t;
+ bool strict_type_match = false;
+ const struct btf *reg_btf;
+ const char *reg_ref_tname;
+ u32 reg_ref_id;
+
+ if (base_type(reg->type) == PTR_TO_BTF_ID) {
+ reg_btf = reg->btf;
+ reg_ref_id = reg->btf_id;
+ } else {
+ reg_btf = btf_vmlinux;
+ reg_ref_id = *reg2btf_ids[base_type(reg->type)];
+ }
+
+ if (is_kfunc_trusted_args(meta) || (is_kfunc_release(meta) && reg->ref_obj_id))
+ strict_type_match = true;
+
+ reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id, &reg_ref_id);
+ reg_ref_tname = btf_name_by_offset(reg_btf, reg_ref_t->name_off);
+ if (!btf_struct_ids_match(&env->log, reg_btf, reg_ref_id, reg->off, meta->btf, ref_id, strict_type_match)) {
+ verbose(env, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
+ meta->func_name, argno, btf_type_str(ref_t), ref_tname, argno + 1,
+ btf_type_str(reg_ref_t), reg_ref_tname);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int process_kf_arg_ptr_to_kptr(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ const struct btf_type *ref_t,
+ const char *ref_tname,
+ struct bpf_kfunc_call_arg_meta *meta,
+ int argno)
+{
+ struct btf_field *kptr_field;
+
+ /* check_func_arg_reg_off allows var_off for
+ * PTR_TO_MAP_VALUE, but we need fixed offset to find
+ * off_desc.
+ */
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env, "arg#0 must have constant offset\n");
+ return -EINVAL;
+ }
+
+ kptr_field = btf_record_find(reg->map_ptr->record, reg->off + reg->var_off.value, BPF_KPTR);
+ if (!kptr_field || kptr_field->type != BPF_KPTR_REF) {
+ verbose(env, "arg#0 no referenced kptr at map value offset=%llu\n",
+ reg->off + reg->var_off.value);
+ return -EINVAL;
+ }
+
+ if (!btf_struct_ids_match(&env->log, meta->btf, ref_t->type, 0, kptr_field->kptr.btf,
+ kptr_field->kptr.btf_id, true)) {
+ verbose(env, "kernel function %s args#%d expected pointer to %s %s\n",
+ meta->func_name, argno, btf_type_str(ref_t), ref_tname);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int ref_set_release_on_unlock(struct bpf_verifier_env *env, u32 ref_obj_id)
+{
+ struct bpf_func_state *state = cur_func(env);
+ struct bpf_reg_state *reg;
+ int i;
+
+ /* bpf_spin_lock only allows calling list_push and list_pop, no BPF
+ * subprogs, no global functions. This means that the references would
+ * not be released inside the critical section but they may be added to
+ * the reference state, and the acquired_refs are never copied out for a
+ * different frame as BPF to BPF calls don't work in bpf_spin_lock
+ * critical sections.
+ */
+ if (!ref_obj_id) {
+ verbose(env, "verifier internal error: ref_obj_id is zero for release_on_unlock\n");
+ return -EFAULT;
+ }
+ for (i = 0; i < state->acquired_refs; i++) {
+ if (state->refs[i].id == ref_obj_id) {
+ if (state->refs[i].release_on_unlock) {
+ verbose(env, "verifier internal error: expected false release_on_unlock");
+ return -EFAULT;
+ }
+ state->refs[i].release_on_unlock = true;
+ /* Now mark everyone sharing same ref_obj_id as untrusted */
+ bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
+ if (reg->ref_obj_id == ref_obj_id)
+ reg->type |= PTR_UNTRUSTED;
+ }));
+ return 0;
+ }
+ }
+ verbose(env, "verifier internal error: ref state missing for ref_obj_id\n");
+ return -EFAULT;
+}
+
+/* Implementation details:
+ *
+ * Each register points to some region of memory, which we define as an
+ * allocation. Each allocation may embed a bpf_spin_lock which protects any
+ * special BPF objects (bpf_list_head, bpf_rb_root, etc.) part of the same
+ * allocation. The lock and the data it protects are colocated in the same
+ * memory region.
+ *
+ * Hence, everytime a register holds a pointer value pointing to such
+ * allocation, the verifier preserves a unique reg->id for it.
+ *
+ * The verifier remembers the lock 'ptr' and the lock 'id' whenever
+ * bpf_spin_lock is called.
+ *
+ * To enable this, lock state in the verifier captures two values:
+ * active_lock.ptr = Register's type specific pointer
+ * active_lock.id = A unique ID for each register pointer value
+ *
+ * Currently, PTR_TO_MAP_VALUE and PTR_TO_BTF_ID | MEM_ALLOC are the two
+ * supported register types.
+ *
+ * The active_lock.ptr in case of map values is the reg->map_ptr, and in case of
+ * allocated objects is the reg->btf pointer.
+ *
+ * The active_lock.id is non-unique for maps supporting direct_value_addr, as we
+ * can establish the provenance of the map value statically for each distinct
+ * lookup into such maps. They always contain a single map value hence unique
+ * IDs for each pseudo load pessimizes the algorithm and rejects valid programs.
+ *
+ * So, in case of global variables, they use array maps with max_entries = 1,
+ * hence their active_lock.ptr becomes map_ptr and id = 0 (since they all point
+ * into the same map value as max_entries is 1, as described above).
+ *
+ * In case of inner map lookups, the inner map pointer has same map_ptr as the
+ * outer map pointer (in verifier context), but each lookup into an inner map
+ * assigns a fresh reg->id to the lookup, so while lookups into distinct inner
+ * maps from the same outer map share the same map_ptr as active_lock.ptr, they
+ * will get different reg->id assigned to each lookup, hence different
+ * active_lock.id.
+ *
+ * In case of allocated objects, active_lock.ptr is the reg->btf, and the
+ * reg->id is a unique ID preserved after the NULL pointer check on the pointer
+ * returned from bpf_obj_new. Each allocation receives a new reg->id.
+ */
+static int check_reg_allocation_locked(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+ void *ptr;
+ u32 id;
+
+ switch ((int)reg->type) {
+ case PTR_TO_MAP_VALUE:
+ ptr = reg->map_ptr;
+ break;
+ case PTR_TO_BTF_ID | MEM_ALLOC:
+ case PTR_TO_BTF_ID | MEM_ALLOC | PTR_TRUSTED:
+ ptr = reg->btf;
+ break;
+ default:
+ verbose(env, "verifier internal error: unknown reg type for lock check\n");
+ return -EFAULT;
+ }
+ id = reg->id;
+
+ if (!env->cur_state->active_lock.ptr)
+ return -EINVAL;
+ if (env->cur_state->active_lock.ptr != ptr ||
+ env->cur_state->active_lock.id != id) {
+ verbose(env, "held lock and object are not in the same allocation\n");
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static bool is_bpf_list_api_kfunc(u32 btf_id)
+{
+ return btf_id == special_kfunc_list[KF_bpf_list_push_front] ||
+ btf_id == special_kfunc_list[KF_bpf_list_push_back] ||
+ btf_id == special_kfunc_list[KF_bpf_list_pop_front] ||
+ btf_id == special_kfunc_list[KF_bpf_list_pop_back];
+}
+
+static int process_kf_arg_ptr_to_list_head(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, u32 regno,
+ struct bpf_kfunc_call_arg_meta *meta)
+{
+ struct btf_field *field;
+ struct btf_record *rec;
+ u32 list_head_off;
+
+ if (meta->btf != btf_vmlinux || !is_bpf_list_api_kfunc(meta->func_id)) {
+ verbose(env, "verifier internal error: bpf_list_head argument for unknown kfunc\n");
+ return -EFAULT;
+ }
+
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env,
+ "R%d doesn't have constant offset. bpf_list_head has to be at the constant offset\n",
+ regno);
+ return -EINVAL;
+ }
+
+ rec = reg_btf_record(reg);
+ list_head_off = reg->off + reg->var_off.value;
+ field = btf_record_find(rec, list_head_off, BPF_LIST_HEAD);
+ if (!field) {
+ verbose(env, "bpf_list_head not found at offset=%u\n", list_head_off);
+ return -EINVAL;
+ }
+
+ /* All functions require bpf_list_head to be protected using a bpf_spin_lock */
+ if (check_reg_allocation_locked(env, reg)) {
+ verbose(env, "bpf_spin_lock at off=%d must be held for bpf_list_head\n",
+ rec->spin_lock_off);
+ return -EINVAL;
+ }
+
+ if (meta->arg_list_head.field) {
+ verbose(env, "verifier internal error: repeating bpf_list_head arg\n");
+ return -EFAULT;
+ }
+ meta->arg_list_head.field = field;
+ return 0;
+}
+
+static int process_kf_arg_ptr_to_list_node(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg, u32 regno,
+ struct bpf_kfunc_call_arg_meta *meta)
+{
+ const struct btf_type *et, *t;
+ struct btf_field *field;
+ struct btf_record *rec;
+ u32 list_node_off;
+
+ if (meta->btf != btf_vmlinux ||
+ (meta->func_id != special_kfunc_list[KF_bpf_list_push_front] &&
+ meta->func_id != special_kfunc_list[KF_bpf_list_push_back])) {
+ verbose(env, "verifier internal error: bpf_list_node argument for unknown kfunc\n");
+ return -EFAULT;
+ }
+
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env,
+ "R%d doesn't have constant offset. bpf_list_node has to be at the constant offset\n",
+ regno);
+ return -EINVAL;
+ }
+
+ rec = reg_btf_record(reg);
+ list_node_off = reg->off + reg->var_off.value;
+ field = btf_record_find(rec, list_node_off, BPF_LIST_NODE);
+ if (!field || field->offset != list_node_off) {
+ verbose(env, "bpf_list_node not found at offset=%u\n", list_node_off);
+ return -EINVAL;
+ }
+
+ field = meta->arg_list_head.field;
+
+ et = btf_type_by_id(field->list_head.btf, field->list_head.value_btf_id);
+ t = btf_type_by_id(reg->btf, reg->btf_id);
+ if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, 0, field->list_head.btf,
+ field->list_head.value_btf_id, true)) {
+ verbose(env, "operation on bpf_list_head expects arg#1 bpf_list_node at offset=%d "
+ "in struct %s, but arg is at offset=%d in struct %s\n",
+ field->list_head.node_offset, btf_name_by_offset(field->list_head.btf, et->name_off),
+ list_node_off, btf_name_by_offset(reg->btf, t->name_off));
+ return -EINVAL;
+ }
+
+ if (list_node_off != field->list_head.node_offset) {
+ verbose(env, "arg#1 offset=%d, but expected bpf_list_node at offset=%d in struct %s\n",
+ list_node_off, field->list_head.node_offset,
+ btf_name_by_offset(field->list_head.btf, et->name_off));
+ return -EINVAL;
+ }
+ /* Set arg#1 for expiration after unlock */
+ return ref_set_release_on_unlock(env, reg->ref_obj_id);
+}
+
+static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta)
+{
+ const char *func_name = meta->func_name, *ref_tname;
+ const struct btf *btf = meta->btf;
+ const struct btf_param *args;
+ u32 i, nargs;
+ int ret;
+
+ args = (const struct btf_param *)(meta->func_proto + 1);
+ nargs = btf_type_vlen(meta->func_proto);
+ if (nargs > MAX_BPF_FUNC_REG_ARGS) {
+ verbose(env, "Function %s has %d > %d args\n", func_name, nargs,
+ MAX_BPF_FUNC_REG_ARGS);
+ return -EINVAL;
+ }
+
+ /* Check that BTF function arguments match actual types that the
+ * verifier sees.
+ */
+ for (i = 0; i < nargs; i++) {
+ struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[i + 1];
+ const struct btf_type *t, *ref_t, *resolve_ret;
+ enum bpf_arg_type arg_type = ARG_DONTCARE;
+ u32 regno = i + 1, ref_id, type_size;
+ bool is_ret_buf_sz = false;
+ int kf_arg_type;
+
+ t = btf_type_skip_modifiers(btf, args[i].type, NULL);
+
+ if (is_kfunc_arg_ignore(btf, &args[i]))
+ continue;
+
+ if (btf_type_is_scalar(t)) {
+ if (reg->type != SCALAR_VALUE) {
+ verbose(env, "R%d is not a scalar\n", regno);
+ return -EINVAL;
+ }
+
+ if (is_kfunc_arg_constant(meta->btf, &args[i])) {
+ if (meta->arg_constant.found) {
+ verbose(env, "verifier internal error: only one constant argument permitted\n");
+ return -EFAULT;
+ }
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env, "R%d must be a known constant\n", regno);
+ return -EINVAL;
+ }
+ ret = mark_chain_precision(env, regno);
+ if (ret < 0)
+ return ret;
+ meta->arg_constant.found = true;
+ meta->arg_constant.value = reg->var_off.value;
+ } else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdonly_buf_size")) {
+ meta->r0_rdonly = true;
+ is_ret_buf_sz = true;
+ } else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdwr_buf_size")) {
+ is_ret_buf_sz = true;
+ }
+
+ if (is_ret_buf_sz) {
+ if (meta->r0_size) {
+ verbose(env, "2 or more rdonly/rdwr_buf_size parameters for kfunc");
+ return -EINVAL;
+ }
+
+ if (!tnum_is_const(reg->var_off)) {
+ verbose(env, "R%d is not a const\n", regno);
+ return -EINVAL;
+ }
+
+ meta->r0_size = reg->var_off.value;
+ ret = mark_chain_precision(env, regno);
+ if (ret)
+ return ret;
+ }
+ continue;
+ }
+
+ if (!btf_type_is_ptr(t)) {
+ verbose(env, "Unrecognized arg#%d type %s\n", i, btf_type_str(t));
+ return -EINVAL;
+ }
+
+ if (reg->ref_obj_id) {
+ if (is_kfunc_release(meta) && meta->ref_obj_id) {
+ verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
+ regno, reg->ref_obj_id,
+ meta->ref_obj_id);
+ return -EFAULT;
+ }
+ meta->ref_obj_id = reg->ref_obj_id;
+ if (is_kfunc_release(meta))
+ meta->release_regno = regno;
+ }
+
+ ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
+ ref_tname = btf_name_by_offset(btf, ref_t->name_off);
+
+ kf_arg_type = get_kfunc_ptr_arg_type(env, meta, t, ref_t, ref_tname, args, i, nargs);
+ if (kf_arg_type < 0)
+ return kf_arg_type;
+
+ switch (kf_arg_type) {
+ case KF_ARG_PTR_TO_ALLOC_BTF_ID:
+ case KF_ARG_PTR_TO_BTF_ID:
+ if (!is_kfunc_trusted_args(meta))
+ break;
+
+ if (!is_trusted_reg(reg)) {
+ verbose(env, "R%d must be referenced or trusted\n", regno);
+ return -EINVAL;
+ }
+ fallthrough;
+ case KF_ARG_PTR_TO_CTX:
+ /* Trusted arguments have the same offset checks as release arguments */
+ arg_type |= OBJ_RELEASE;
+ break;
+ case KF_ARG_PTR_TO_KPTR:
+ case KF_ARG_PTR_TO_DYNPTR:
+ case KF_ARG_PTR_TO_LIST_HEAD:
+ case KF_ARG_PTR_TO_LIST_NODE:
+ case KF_ARG_PTR_TO_MEM:
+ case KF_ARG_PTR_TO_MEM_SIZE:
+ /* Trusted by default */
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return -EFAULT;
+ }
+
+ if (is_kfunc_release(meta) && reg->ref_obj_id)
+ arg_type |= OBJ_RELEASE;
+ ret = check_func_arg_reg_off(env, reg, regno, arg_type);
+ if (ret < 0)
+ return ret;
+
+ switch (kf_arg_type) {
+ case KF_ARG_PTR_TO_CTX:
+ if (reg->type != PTR_TO_CTX) {
+ verbose(env, "arg#%d expected pointer to ctx, but got %s\n", i, btf_type_str(t));
+ return -EINVAL;
+ }
+
+ if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) {
+ ret = get_kern_ctx_btf_id(&env->log, resolve_prog_type(env->prog));
+ if (ret < 0)
+ return -EINVAL;
+ meta->ret_btf_id = ret;
+ }
+ break;
+ case KF_ARG_PTR_TO_ALLOC_BTF_ID:
+ if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+ verbose(env, "arg#%d expected pointer to allocated object\n", i);
+ return -EINVAL;
+ }
+ if (!reg->ref_obj_id) {
+ verbose(env, "allocated object must be referenced\n");
+ return -EINVAL;
+ }
+ if (meta->btf == btf_vmlinux &&
+ meta->func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
+ meta->arg_obj_drop.btf = reg->btf;
+ meta->arg_obj_drop.btf_id = reg->btf_id;
+ }
+ break;
+ case KF_ARG_PTR_TO_KPTR:
+ if (reg->type != PTR_TO_MAP_VALUE) {
+ verbose(env, "arg#0 expected pointer to map value\n");
+ return -EINVAL;
+ }
+ ret = process_kf_arg_ptr_to_kptr(env, reg, ref_t, ref_tname, meta, i);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_DYNPTR:
+ if (reg->type != PTR_TO_STACK) {
+ verbose(env, "arg#%d expected pointer to stack\n", i);
+ return -EINVAL;
+ }
+
+ if (!is_dynptr_reg_valid_init(env, reg)) {
+ verbose(env, "arg#%d pointer type %s %s must be valid and initialized\n",
+ i, btf_type_str(ref_t), ref_tname);
+ return -EINVAL;
+ }
+
+ if (!is_dynptr_type_expected(env, reg, ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL)) {
+ verbose(env, "arg#%d pointer type %s %s points to unsupported dynamic pointer type\n",
+ i, btf_type_str(ref_t), ref_tname);
+ return -EINVAL;
+ }
+ break;
+ case KF_ARG_PTR_TO_LIST_HEAD:
+ if (reg->type != PTR_TO_MAP_VALUE &&
+ reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+ verbose(env, "arg#%d expected pointer to map value or allocated object\n", i);
+ return -EINVAL;
+ }
+ if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC) && !reg->ref_obj_id) {
+ verbose(env, "allocated object must be referenced\n");
+ return -EINVAL;
+ }
+ ret = process_kf_arg_ptr_to_list_head(env, reg, regno, meta);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_LIST_NODE:
+ if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+ verbose(env, "arg#%d expected pointer to allocated object\n", i);
+ return -EINVAL;
+ }
+ if (!reg->ref_obj_id) {
+ verbose(env, "allocated object must be referenced\n");
+ return -EINVAL;
+ }
+ ret = process_kf_arg_ptr_to_list_node(env, reg, regno, meta);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_BTF_ID:
+ /* Only base_type is checked, further checks are done here */
+ if ((base_type(reg->type) != PTR_TO_BTF_ID ||
+ bpf_type_has_unsafe_modifiers(reg->type)) &&
+ !reg2btf_ids[base_type(reg->type)]) {
+ verbose(env, "arg#%d is %s ", i, reg_type_str(env, reg->type));
+ verbose(env, "expected %s or socket\n",
+ reg_type_str(env, base_type(reg->type) |
+ (type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS)));
+ return -EINVAL;
+ }
+ ret = process_kf_arg_ptr_to_btf_id(env, reg, ref_t, ref_tname, ref_id, meta, i);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_MEM:
+ resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
+ if (IS_ERR(resolve_ret)) {
+ verbose(env, "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
+ i, btf_type_str(ref_t), ref_tname, PTR_ERR(resolve_ret));
+ return -EINVAL;
+ }
+ ret = check_mem_reg(env, reg, regno, type_size);
+ if (ret < 0)
+ return ret;
+ break;
+ case KF_ARG_PTR_TO_MEM_SIZE:
+ ret = check_kfunc_mem_size_reg(env, &regs[regno + 1], regno + 1);
+ if (ret < 0) {
+ verbose(env, "arg#%d arg#%d memory, len pair leads to invalid memory access\n", i, i + 1);
+ return ret;
+ }
+ /* Skip next '__sz' argument */
+ i++;
+ break;
+ }
+ }
+
+ if (is_kfunc_release(meta) && !meta->release_regno) {
+ verbose(env, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
+ func_name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
int *insn_idx_p)
{
const struct btf_type *t, *func, *func_proto, *ptr_type;
struct bpf_reg_state *regs = cur_regs(env);
- struct bpf_kfunc_arg_meta meta = { 0 };
const char *func_name, *ptr_type_name;
+ bool sleepable, rcu_lock, rcu_unlock;
+ struct bpf_kfunc_call_arg_meta meta;
u32 i, nargs, func_id, ptr_type_id;
int err, insn_idx = *insn_idx_p;
const struct btf_param *args;
+ const struct btf_type *ret_t;
struct btf *desc_btf;
u32 *kfunc_flags;
- bool acq;
/* skip for now, but return error when we find this in fixup_kfunc_call */
if (!insn->imm)
@@ -7830,24 +8905,68 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
func_name);
return -EACCES;
}
- if (*kfunc_flags & KF_DESTRUCTIVE && !capable(CAP_SYS_BOOT)) {
- verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capabilities\n");
+
+ /* Prepare kfunc call metadata */
+ memset(&meta, 0, sizeof(meta));
+ meta.btf = desc_btf;
+ meta.func_id = func_id;
+ meta.kfunc_flags = *kfunc_flags;
+ meta.func_proto = func_proto;
+ meta.func_name = func_name;
+
+ if (is_kfunc_destructive(&meta) && !capable(CAP_SYS_BOOT)) {
+ verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capability\n");
+ return -EACCES;
+ }
+
+ sleepable = is_kfunc_sleepable(&meta);
+ if (sleepable && !env->prog->aux->sleepable) {
+ verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name);
+ return -EACCES;
+ }
+
+ rcu_lock = is_kfunc_bpf_rcu_read_lock(&meta);
+ rcu_unlock = is_kfunc_bpf_rcu_read_unlock(&meta);
+ if ((rcu_lock || rcu_unlock) && !env->rcu_tag_supported) {
+ verbose(env, "no vmlinux btf rcu tag support for kfunc %s\n", func_name);
return -EACCES;
}
- acq = *kfunc_flags & KF_ACQUIRE;
+ if (env->cur_state->active_rcu_lock) {
+ struct bpf_func_state *state;
+ struct bpf_reg_state *reg;
- meta.flags = *kfunc_flags;
+ if (rcu_lock) {
+ verbose(env, "nested rcu read lock (kernel function %s)\n", func_name);
+ return -EINVAL;
+ } else if (rcu_unlock) {
+ bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
+ if (reg->type & MEM_RCU) {
+ reg->type &= ~(MEM_RCU | PTR_TRUSTED);
+ reg->type |= PTR_UNTRUSTED;
+ }
+ }));
+ env->cur_state->active_rcu_lock = false;
+ } else if (sleepable) {
+ verbose(env, "kernel func %s is sleepable within rcu_read_lock region\n", func_name);
+ return -EACCES;
+ }
+ } else if (rcu_lock) {
+ env->cur_state->active_rcu_lock = true;
+ } else if (rcu_unlock) {
+ verbose(env, "unmatched rcu read unlock (kernel function %s)\n", func_name);
+ return -EINVAL;
+ }
/* Check the arguments */
- err = btf_check_kfunc_arg_match(env, desc_btf, func_id, regs, &meta);
+ err = check_kfunc_args(env, &meta);
if (err < 0)
return err;
/* In case of release function, we get register number of refcounted
- * PTR_TO_BTF_ID back from btf_check_kfunc_arg_match, do the release now
+ * PTR_TO_BTF_ID in bpf_kfunc_arg_meta, do the release now.
*/
- if (err) {
- err = release_reference(env, regs[err].ref_obj_id);
+ if (meta.release_regno) {
+ err = release_reference(env, regs[meta.release_regno].ref_obj_id);
if (err) {
verbose(env, "kfunc %s#%d reference has not been acquired before\n",
func_name, func_id);
@@ -7861,18 +8980,92 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
/* Check return type */
t = btf_type_skip_modifiers(desc_btf, func_proto->type, NULL);
- if (acq && !btf_type_is_struct_ptr(desc_btf, t)) {
- verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n");
- return -EINVAL;
+ if (is_kfunc_acquire(&meta) && !btf_type_is_struct_ptr(meta.btf, t)) {
+ /* Only exception is bpf_obj_new_impl */
+ if (meta.btf != btf_vmlinux || meta.func_id != special_kfunc_list[KF_bpf_obj_new_impl]) {
+ verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n");
+ return -EINVAL;
+ }
}
if (btf_type_is_scalar(t)) {
mark_reg_unknown(env, regs, BPF_REG_0);
mark_btf_func_reg_size(env, BPF_REG_0, t->size);
} else if (btf_type_is_ptr(t)) {
- ptr_type = btf_type_skip_modifiers(desc_btf, t->type,
- &ptr_type_id);
- if (!btf_type_is_struct(ptr_type)) {
+ ptr_type = btf_type_skip_modifiers(desc_btf, t->type, &ptr_type_id);
+
+ if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) {
+ if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl]) {
+ struct btf *ret_btf;
+ u32 ret_btf_id;
+
+ if (unlikely(!bpf_global_ma_set))
+ return -ENOMEM;
+
+ if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) {
+ verbose(env, "local type ID argument must be in range [0, U32_MAX]\n");
+ return -EINVAL;
+ }
+
+ ret_btf = env->prog->aux->btf;
+ ret_btf_id = meta.arg_constant.value;
+
+ /* This may be NULL due to user not supplying a BTF */
+ if (!ret_btf) {
+ verbose(env, "bpf_obj_new requires prog BTF\n");
+ return -EINVAL;
+ }
+
+ ret_t = btf_type_by_id(ret_btf, ret_btf_id);
+ if (!ret_t || !__btf_type_is_struct(ret_t)) {
+ verbose(env, "bpf_obj_new type ID argument must be of a struct\n");
+ return -EINVAL;
+ }
+
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
+ regs[BPF_REG_0].btf = ret_btf;
+ regs[BPF_REG_0].btf_id = ret_btf_id;
+
+ env->insn_aux_data[insn_idx].obj_new_size = ret_t->size;
+ env->insn_aux_data[insn_idx].kptr_struct_meta =
+ btf_find_struct_meta(ret_btf, ret_btf_id);
+ } else if (meta.func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
+ env->insn_aux_data[insn_idx].kptr_struct_meta =
+ btf_find_struct_meta(meta.arg_obj_drop.btf,
+ meta.arg_obj_drop.btf_id);
+ } else if (meta.func_id == special_kfunc_list[KF_bpf_list_pop_front] ||
+ meta.func_id == special_kfunc_list[KF_bpf_list_pop_back]) {
+ struct btf_field *field = meta.arg_list_head.field;
+
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
+ regs[BPF_REG_0].btf = field->list_head.btf;
+ regs[BPF_REG_0].btf_id = field->list_head.value_btf_id;
+ regs[BPF_REG_0].off = field->list_head.node_offset;
+ } else if (meta.func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) {
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_TRUSTED;
+ regs[BPF_REG_0].btf = desc_btf;
+ regs[BPF_REG_0].btf_id = meta.ret_btf_id;
+ } else if (meta.func_id == special_kfunc_list[KF_bpf_rdonly_cast]) {
+ ret_t = btf_type_by_id(desc_btf, meta.arg_constant.value);
+ if (!ret_t || !btf_type_is_struct(ret_t)) {
+ verbose(env,
+ "kfunc bpf_rdonly_cast type ID argument must be of a struct\n");
+ return -EINVAL;
+ }
+
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_UNTRUSTED;
+ regs[BPF_REG_0].btf = desc_btf;
+ regs[BPF_REG_0].btf_id = meta.arg_constant.value;
+ } else {
+ verbose(env, "kernel function %s unhandled dynamic return type\n",
+ meta.func_name);
+ return -EFAULT;
+ }
+ } else if (!__btf_type_is_struct(ptr_type)) {
if (!meta.r0_size) {
ptr_type_name = btf_name_by_offset(desc_btf,
ptr_type->name_off);
@@ -7900,20 +9093,24 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
regs[BPF_REG_0].type = PTR_TO_BTF_ID;
regs[BPF_REG_0].btf_id = ptr_type_id;
}
- if (*kfunc_flags & KF_RET_NULL) {
+
+ if (is_kfunc_ret_null(&meta)) {
regs[BPF_REG_0].type |= PTR_MAYBE_NULL;
/* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */
regs[BPF_REG_0].id = ++env->id_gen;
}
mark_btf_func_reg_size(env, BPF_REG_0, sizeof(void *));
- if (acq) {
+ if (is_kfunc_acquire(&meta)) {
int id = acquire_reference_state(env, insn_idx);
if (id < 0)
return id;
- regs[BPF_REG_0].id = id;
+ if (is_kfunc_ret_null(&meta))
+ regs[BPF_REG_0].id = id;
regs[BPF_REG_0].ref_obj_id = id;
}
+ if (reg_may_point_to_spin_lock(&regs[BPF_REG_0]) && !regs[BPF_REG_0].id)
+ regs[BPF_REG_0].id = ++env->id_gen;
} /* else { add_kfunc_call() ensures it is btf_type_is_void(t) } */
nargs = btf_type_vlen(func_proto);
@@ -10086,16 +11283,19 @@ static void mark_ptr_or_null_reg(struct bpf_func_state *state,
{
if (type_may_be_null(reg->type) && reg->id == id &&
!WARN_ON_ONCE(!reg->id)) {
- if (WARN_ON_ONCE(reg->smin_value || reg->smax_value ||
- !tnum_equals_const(reg->var_off, 0) ||
- reg->off)) {
- /* Old offset (both fixed and variable parts) should
- * have been known-zero, because we don't allow pointer
- * arithmetic on pointers that might be NULL. If we
- * see this happening, don't convert the register.
- */
+ /* Old offset (both fixed and variable parts) should have been
+ * known-zero, because we don't allow pointer arithmetic on
+ * pointers that might be NULL. If we see this happening, don't
+ * convert the register.
+ *
+ * But in some cases, some helpers that return local kptrs
+ * advance offset for the returned pointer. In those cases, it
+ * is fine to expect to see reg->off.
+ */
+ if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || !tnum_equals_const(reg->var_off, 0)))
+ return;
+ if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC | PTR_MAYBE_NULL) && WARN_ON_ONCE(reg->off))
return;
- }
if (is_null) {
reg->type = SCALAR_VALUE;
/* We don't need id and ref_obj_id from this point
@@ -10269,6 +11469,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
struct bpf_verifier_state *other_branch;
struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs;
struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL;
+ struct bpf_reg_state *eq_branch_regs;
u8 opcode = BPF_OP(insn->code);
bool is_jmp32;
int pred = -1;
@@ -10378,8 +11579,8 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
/* detect if we are comparing against a constant value so we can adjust
* our min/max values for our dst register.
* this is only legit if both are scalars (or pointers to the same
- * object, I suppose, but we don't support that right now), because
- * otherwise the different base pointers mean the offsets aren't
+ * object, I suppose, see the PTR_MAYBE_NULL related if block below),
+ * because otherwise the different base pointers mean the offsets aren't
* comparable.
*/
if (BPF_SRC(insn->code) == BPF_X) {
@@ -10428,6 +11629,36 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
find_equal_scalars(other_branch, &other_branch_regs[insn->dst_reg]);
}
+ /* if one pointer register is compared to another pointer
+ * register check if PTR_MAYBE_NULL could be lifted.
+ * E.g. register A - maybe null
+ * register B - not null
+ * for JNE A, B, ... - A is not null in the false branch;
+ * for JEQ A, B, ... - A is not null in the true branch.
+ */
+ if (!is_jmp32 && BPF_SRC(insn->code) == BPF_X &&
+ __is_pointer_value(false, src_reg) && __is_pointer_value(false, dst_reg) &&
+ type_may_be_null(src_reg->type) != type_may_be_null(dst_reg->type)) {
+ eq_branch_regs = NULL;
+ switch (opcode) {
+ case BPF_JEQ:
+ eq_branch_regs = other_branch_regs;
+ break;
+ case BPF_JNE:
+ eq_branch_regs = regs;
+ break;
+ default:
+ /* do nothing */
+ break;
+ }
+ if (eq_branch_regs) {
+ if (type_may_be_null(src_reg->type))
+ mark_ptr_not_null_reg(&eq_branch_regs[insn->src_reg]);
+ else
+ mark_ptr_not_null_reg(&eq_branch_regs[insn->dst_reg]);
+ }
+ }
+
/* detect if R == 0 where R is returned from bpf_map_lookup_elem().
* NOTE: these optimizations below are related with pointer comparison
* which will never be JMP32.
@@ -10534,8 +11765,8 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE) {
dst_reg->type = PTR_TO_MAP_VALUE;
dst_reg->off = aux->map_off;
- if (btf_record_has_field(map->record, BPF_SPIN_LOCK))
- dst_reg->id = ++env->id_gen;
+ WARN_ON_ONCE(map->max_entries != 1);
+ /* We want reg->id to be same (0) as map_value is not distinct */
} else if (insn->src_reg == BPF_PSEUDO_MAP_FD ||
insn->src_reg == BPF_PSEUDO_MAP_IDX) {
dst_reg->type = CONST_PTR_TO_MAP;
@@ -10613,11 +11844,16 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
return err;
}
- if (env->cur_state->active_spin_lock) {
+ if (env->cur_state->active_lock.ptr) {
verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n");
return -EINVAL;
}
+ if (env->cur_state->active_rcu_lock) {
+ verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_rcu_read_lock-ed region\n");
+ return -EINVAL;
+ }
+
if (regs[ctx_reg].type != PTR_TO_CTX) {
verbose(env,
"at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
@@ -11879,7 +13115,11 @@ static bool states_equal(struct bpf_verifier_env *env,
if (old->speculative && !cur->speculative)
return false;
- if (old->active_spin_lock != cur->active_spin_lock)
+ if (old->active_lock.ptr != cur->active_lock.ptr ||
+ old->active_lock.id != cur->active_lock.id)
+ return false;
+
+ if (old->active_rcu_lock != cur->active_rcu_lock)
return false;
/* for states to be equal callsites have to be the same
@@ -12524,11 +13764,14 @@ static int do_check(struct bpf_verifier_env *env)
return -EINVAL;
}
- if (env->cur_state->active_spin_lock &&
- (insn->src_reg == BPF_PSEUDO_CALL ||
- insn->imm != BPF_FUNC_spin_unlock)) {
- verbose(env, "function calls are not allowed while holding a lock\n");
- return -EINVAL;
+ if (env->cur_state->active_lock.ptr) {
+ if ((insn->src_reg == BPF_REG_0 && insn->imm != BPF_FUNC_spin_unlock) ||
+ (insn->src_reg == BPF_PSEUDO_CALL) ||
+ (insn->src_reg == BPF_PSEUDO_KFUNC_CALL &&
+ (insn->off != 0 || !is_bpf_list_api_kfunc(insn->imm)))) {
+ verbose(env, "function calls are not allowed while holding a lock\n");
+ return -EINVAL;
+ }
}
if (insn->src_reg == BPF_PSEUDO_CALL)
err = check_func_call(env, insn, &env->insn_idx);
@@ -12561,11 +13804,16 @@ static int do_check(struct bpf_verifier_env *env)
return -EINVAL;
}
- if (env->cur_state->active_spin_lock) {
+ if (env->cur_state->active_lock.ptr) {
verbose(env, "bpf_spin_unlock is missing\n");
return -EINVAL;
}
+ if (env->cur_state->active_rcu_lock) {
+ verbose(env, "bpf_rcu_read_unlock is missing\n");
+ return -EINVAL;
+ }
+
/* We must do check_reference_leak here before
* prepare_func_exit to handle the case when
* state->curframe > 0, it may be a callback
@@ -12818,6 +14066,13 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env,
{
enum bpf_prog_type prog_type = resolve_prog_type(prog);
+ if (btf_record_has_field(map->record, BPF_LIST_HEAD)) {
+ if (is_tracing_prog_type(prog_type)) {
+ verbose(env, "tracing progs cannot use bpf_list_head yet\n");
+ return -EINVAL;
+ }
+ }
+
if (btf_record_has_field(map->record, BPF_SPIN_LOCK)) {
if (prog_type == BPF_PROG_TYPE_SOCKET_FILTER) {
verbose(env, "socket filter progs cannot use bpf_spin_lock yet\n");
@@ -13654,6 +14909,13 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
break;
case PTR_TO_BTF_ID:
case PTR_TO_BTF_ID | PTR_UNTRUSTED:
+ /* PTR_TO_BTF_ID | MEM_ALLOC always has a valid lifetime, unlike
+ * PTR_TO_BTF_ID, and an active ref_obj_id, but the same cannot
+ * be said once it is marked PTR_UNTRUSTED, hence we must handle
+ * any faults for loads into such types. BPF_WRITE is disallowed
+ * for this case.
+ */
+ case PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED:
if (type == BPF_READ) {
insn->code = BPF_LDX | BPF_PROBE_MEM |
BPF_SIZE((insn)->code);
@@ -14019,8 +15281,8 @@ static int fixup_call_args(struct bpf_verifier_env *env)
return err;
}
-static int fixup_kfunc_call(struct bpf_verifier_env *env,
- struct bpf_insn *insn)
+static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ struct bpf_insn *insn_buf, int insn_idx, int *cnt)
{
const struct bpf_kfunc_desc *desc;
@@ -14039,8 +15301,33 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env,
return -EFAULT;
}
+ *cnt = 0;
insn->imm = desc->imm;
-
+ if (insn->off)
+ return 0;
+ if (desc->func_id == special_kfunc_list[KF_bpf_obj_new_impl]) {
+ struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
+ struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
+ u64 obj_new_size = env->insn_aux_data[insn_idx].obj_new_size;
+
+ insn_buf[0] = BPF_MOV64_IMM(BPF_REG_1, obj_new_size);
+ insn_buf[1] = addr[0];
+ insn_buf[2] = addr[1];
+ insn_buf[3] = *insn;
+ *cnt = 4;
+ } else if (desc->func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
+ struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
+ struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
+
+ insn_buf[0] = addr[0];
+ insn_buf[1] = addr[1];
+ insn_buf[2] = *insn;
+ *cnt = 3;
+ } else if (desc->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx] ||
+ desc->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) {
+ insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1);
+ *cnt = 1;
+ }
return 0;
}
@@ -14182,9 +15469,19 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
if (insn->src_reg == BPF_PSEUDO_CALL)
continue;
if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
- ret = fixup_kfunc_call(env, insn);
+ ret = fixup_kfunc_call(env, insn, insn_buf, i + delta, &cnt);
if (ret)
return ret;
+ if (cnt == 0)
+ continue;
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
continue;
}
@@ -14302,14 +15599,12 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
goto patch_call_imm;
}
- if (insn->imm == BPF_FUNC_task_storage_get ||
- insn->imm == BPF_FUNC_sk_storage_get ||
- insn->imm == BPF_FUNC_inode_storage_get ||
- insn->imm == BPF_FUNC_cgrp_storage_get) {
- if (env->prog->aux->sleepable)
- insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_KERNEL);
- else
+ if (is_storage_get_function(insn->imm)) {
+ if (!env->prog->aux->sleepable ||
+ env->insn_aux_data[i + delta].storage_get_func_atomic)
insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_ATOMIC);
+ else
+ insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_KERNEL);
insn_buf[1] = *insn;
cnt = 2;
@@ -14379,7 +15674,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
BUILD_BUG_ON(!__same_type(ops->map_peek_elem,
(int (*)(struct bpf_map *map, void *value))NULL));
BUILD_BUG_ON(!__same_type(ops->map_redirect,
- (int (*)(struct bpf_map *map, u32 ifindex, u64 flags))NULL));
+ (int (*)(struct bpf_map *map, u64 index, u64 flags))NULL));
BUILD_BUG_ON(!__same_type(ops->map_for_each_callback,
(int (*)(struct bpf_map *map,
bpf_callback_t callback_fn,
@@ -15388,6 +16683,8 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr)
env->bypass_spec_v1 = bpf_bypass_spec_v1();
env->bypass_spec_v4 = bpf_bypass_spec_v4();
env->bpf_capable = bpf_capable();
+ env->rcu_tag_supported = btf_vmlinux &&
+ btf_find_by_name_kind(btf_vmlinux, "rcu", BTF_KIND_TYPE_TAG) > 0;
if (is_priv)
env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
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