Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
bpf-next 2023-01-04

We've added 45 non-merge commits during the last 21 day(s) which contain
a total of 50 files changed, 1454 insertions(+), 375 deletions(-).

The main changes are:

1) Fixes, improvements and refactoring of parts of BPF verifier's
   state equivalence checks, from Andrii Nakryiko.

2) Fix a few corner cases in libbpf's BTF-to-C converter in particular
   around padding handling and enums, also from Andrii Nakryiko.

3) Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better
  support decap on GRE tunnel devices not operating in collect metadata,
  from Christian Ehrig.

4) Improve x86 JIT's codegen for PROBE_MEM runtime error checks,
   from Dave Marchevsky.

5) Remove the need for trace_printk_lock for bpf_trace_printk
   and bpf_trace_vprintk helpers, from Jiri Olsa.

6) Add proper documentation for BPF_MAP_TYPE_SOCK{MAP,HASH} maps,
   from Maryam Tahhan.

7) Improvements in libbpf's btf_parse_elf error handling, from Changbin Du.

8) Bigger batch of improvements to BPF tracing code samples,
   from Daniel T. Lee.

9) Add LoongArch support to libbpf's bpf_tracing helper header,
   from Hengqi Chen.

10) Fix a libbpf compiler warning in perf_event_open_probe on arm32,
    from Khem Raj.

11) Optimize bpf_local_storage_elem by removing 56 bytes of padding,
    from Martin KaFai Lau.

12) Use pkg-config to locate libelf for resolve_btfids build,
    from Shen Jiamin.

13) Various libbpf improvements around API documentation and errno
    handling, from Xin Liu.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (45 commits)
  libbpf: Return -ENODATA for missing btf section
  libbpf: Add LoongArch support to bpf_tracing.h
  libbpf: Restore errno after pr_warn.
  libbpf: Added the description of some API functions
  libbpf: Fix invalid return address register in s390
  samples/bpf: Use BPF_KSYSCALL macro in syscall tracing programs
  samples/bpf: Fix tracex2 by using BPF_KSYSCALL macro
  samples/bpf: Change _kern suffix to .bpf with syscall tracing program
  samples/bpf: Use vmlinux.h instead of implicit headers in syscall tracing program
  samples/bpf: Use kyscall instead of kprobe in syscall tracing program
  bpf: rename list_head -> graph_root in field info types
  libbpf: fix errno is overwritten after being closed.
  bpf: fix regs_exact() logic in regsafe() to remap IDs correctly
  bpf: perform byte-by-byte comparison only when necessary in regsafe()
  bpf: reject non-exact register type matches in regsafe()
  bpf: generalize MAYBE_NULL vs non-MAYBE_NULL rule
  bpf: reorganize struct bpf_reg_state fields
  bpf: teach refsafe() to take into account ID remapping
  bpf: Remove unused field initialization in bpf's ctl_table
  selftests/bpf: Add jit probe_mem corner case tests to s390x denylist
  ...
====================

Link: https://lore.kernel.org/r/20230105000926.31350-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 41 insertions, 30 deletions

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index af30c6cbd65d..458db2db2f81 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -756,19 +756,20 @@ static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
 /* Per-cpu temp buffers used by printf-like helpers to store the bprintf binary
  * arguments representation.
  */
-#define MAX_BPRINTF_BUF_LEN	512
+#define MAX_BPRINTF_BIN_ARGS	512
 
 /* Support executing three nested bprintf helper calls on a given CPU */
 #define MAX_BPRINTF_NEST_LEVEL	3
 struct bpf_bprintf_buffers {
-	char tmp_bufs[MAX_BPRINTF_NEST_LEVEL][MAX_BPRINTF_BUF_LEN];
+	char bin_args[MAX_BPRINTF_BIN_ARGS];
+	char buf[MAX_BPRINTF_BUF];
 };
-static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
+
+static DEFINE_PER_CPU(struct bpf_bprintf_buffers[MAX_BPRINTF_NEST_LEVEL], bpf_bprintf_bufs);
 static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
 
-static int try_get_fmt_tmp_buf(char **tmp_buf)
+static int try_get_buffers(struct bpf_bprintf_buffers **bufs)
 {
-	struct bpf_bprintf_buffers *bufs;
 	int nest_level;
 
 	preempt_disable();
@@ -778,18 +779,19 @@ static int try_get_fmt_tmp_buf(char **tmp_buf)
 		preempt_enable();
 		return -EBUSY;
 	}
-	bufs = this_cpu_ptr(&bpf_bprintf_bufs);
-	*tmp_buf = bufs->tmp_bufs[nest_level - 1];
+	*bufs = this_cpu_ptr(&bpf_bprintf_bufs[nest_level - 1]);
 
 	return 0;
 }
 
-void bpf_bprintf_cleanup(void)
+void bpf_bprintf_cleanup(struct bpf_bprintf_data *data)
 {
-	if (this_cpu_read(bpf_bprintf_nest_level)) {
-		this_cpu_dec(bpf_bprintf_nest_level);
-		preempt_enable();
-	}
+	if (!data->bin_args && !data->buf)
+		return;
+	if (WARN_ON_ONCE(this_cpu_read(bpf_bprintf_nest_level) == 0))
+		return;
+	this_cpu_dec(bpf_bprintf_nest_level);
+	preempt_enable();
 }
 
 /*
@@ -798,18 +800,20 @@ void bpf_bprintf_cleanup(void)
  * Returns a negative value if fmt is an invalid format string or 0 otherwise.
  *
  * This can be used in two ways:
- * - Format string verification only: when bin_args is NULL
+ * - Format string verification only: when data->get_bin_args is false
  * - Arguments preparation: in addition to the above verification, it writes in
- *   bin_args a binary representation of arguments usable by bstr_printf where
- *   pointers from BPF have been sanitized.
+ *   data->bin_args a binary representation of arguments usable by bstr_printf
+ *   where pointers from BPF have been sanitized.
  *
  * In argument preparation mode, if 0 is returned, safe temporary buffers are
  * allocated and bpf_bprintf_cleanup should be called to free them after use.
  */
 int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
-			u32 **bin_args, u32 num_args)
+			u32 num_args, struct bpf_bprintf_data *data)
 {
+	bool get_buffers = (data->get_bin_args && num_args) || data->get_buf;
 	char *unsafe_ptr = NULL, *tmp_buf = NULL, *tmp_buf_end, *fmt_end;
+	struct bpf_bprintf_buffers *buffers = NULL;
 	size_t sizeof_cur_arg, sizeof_cur_ip;
 	int err, i, num_spec = 0;
 	u64 cur_arg;
@@ -820,14 +824,19 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
 		return -EINVAL;
 	fmt_size = fmt_end - fmt;
 
-	if (bin_args) {
-		if (num_args && try_get_fmt_tmp_buf(&tmp_buf))
-			return -EBUSY;
+	if (get_buffers && try_get_buffers(&buffers))
+		return -EBUSY;
 
-		tmp_buf_end = tmp_buf + MAX_BPRINTF_BUF_LEN;
-		*bin_args = (u32 *)tmp_buf;
+	if (data->get_bin_args) {
+		if (num_args)
+			tmp_buf = buffers->bin_args;
+		tmp_buf_end = tmp_buf + MAX_BPRINTF_BIN_ARGS;
+		data->bin_args = (u32 *)tmp_buf;
 	}
 
+	if (data->get_buf)
+		data->buf = buffers->buf;
+
 	for (i = 0; i < fmt_size; i++) {
 		if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) {
 			err = -EINVAL;
@@ -1021,31 +1030,33 @@ nocopy_fmt:
 	err = 0;
 out:
 	if (err)
-		bpf_bprintf_cleanup();
+		bpf_bprintf_cleanup(data);
 	return err;
 }
 
 BPF_CALL_5(bpf_snprintf, char *, str, u32, str_size, char *, fmt,
-	   const void *, data, u32, data_len)
+	   const void *, args, u32, data_len)
 {
+	struct bpf_bprintf_data data = {
+		.get_bin_args	= true,
+	};
 	int err, num_args;
-	u32 *bin_args;
 
 	if (data_len % 8 || data_len > MAX_BPRINTF_VARARGS * 8 ||
-	    (data_len && !data))
+	    (data_len && !args))
 		return -EINVAL;
 	num_args = data_len / 8;
 
 	/* ARG_PTR_TO_CONST_STR guarantees that fmt is zero-terminated so we
 	 * can safely give an unbounded size.
 	 */
-	err = bpf_bprintf_prepare(fmt, UINT_MAX, data, &bin_args, num_args);
+	err = bpf_bprintf_prepare(fmt, UINT_MAX, args, num_args, &data);
 	if (err < 0)
 		return err;
 
-	err = bstr_printf(str, str_size, fmt, bin_args);
+	err = bstr_printf(str, str_size, fmt, data.bin_args);
 
-	bpf_bprintf_cleanup();
+	bpf_bprintf_cleanup(&data);
 
 	return err + 1;
 }
@@ -1745,12 +1756,12 @@ unlock:
 	while (head != orig_head) {
 		void *obj = head;
 
-		obj -= field->list_head.node_offset;
+		obj -= field->graph_root.node_offset;
 		head = head->next;
 		/* The contained type can also have resources, including a
 		 * bpf_list_head which needs to be freed.
 		 */
-		bpf_obj_free_fields(field->list_head.value_rec, obj);
+		bpf_obj_free_fields(field->graph_root.value_rec, obj);
 		/* bpf_mem_free requires migrate_disable(), since we can be
 		 * called from map free path as well apart from BPF program (as
 		 * part of map ops doing bpf_obj_free_fields).