From 1bbc55131e59bd099fdc568d3aa0b42634dbd188 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 2 May 2018 21:26:16 -0400 Subject: procfs: get rid of ancient BS in pid_revalidate() uses First of all, calling pid_revalidate() in the end of /* lookups is *not* about closing any kind of races; that used to be true once upon a time, but these days those comments are actively misleading. Especially since pid_revalidate() doesn't even do d_drop() on failure anymore. It doesn't matter, anyway, since once pid_revalidate() starts returning false, ->d_delete() of those dentries starts saying "don't keep"; they won't get stuck in dcache any longer than they are pinned. These calls cannot be just removed, though - the side effect of pid_revalidate() (updating i_uid/i_gid/etc.) is what we are calling it for here. Let's separate the "update ownership" into a new helper (pid_update_inode()) and use it, both in lookups and in pid_revalidate() itself. The comments in pid_revalidate() are also out of date - they refer to the time when pid_revalidate() used to call d_drop() directly... Signed-off-by: Al Viro --- fs/proc/base.c | 55 +++++++++++++++++++++++----------------------------- fs/proc/internal.h | 2 +- fs/proc/namespaces.c | 9 +++------ 3 files changed, 28 insertions(+), 38 deletions(-) (limited to 'fs/proc') diff --git a/fs/proc/base.c b/fs/proc/base.c index eafa39a3a88c..6e0875505898 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1803,15 +1803,22 @@ int pid_getattr(const struct path *path, struct kstat *stat, /* dentry stuff */ /* - * Exceptional case: normally we are not allowed to unhash a busy - * directory. In this case, however, we can do it - no aliasing problems - * due to the way we treat inodes. - * + * Set /... inode ownership (can change due to setuid(), etc.) + */ +void pid_update_inode(struct task_struct *task, struct inode *inode) +{ + task_dump_owner(task, inode->i_mode, &inode->i_uid, &inode->i_gid); + + inode->i_mode &= ~(S_ISUID | S_ISGID); + security_task_to_inode(task, inode); +} + +/* * Rewrite the inode's ownerships here because the owning task may have * performed a setuid(), etc. * */ -int pid_revalidate(struct dentry *dentry, unsigned int flags) +static int pid_revalidate(struct dentry *dentry, unsigned int flags) { struct inode *inode; struct task_struct *task; @@ -1823,10 +1830,7 @@ int pid_revalidate(struct dentry *dentry, unsigned int flags) task = get_proc_task(inode); if (task) { - task_dump_owner(task, inode->i_mode, &inode->i_uid, &inode->i_gid); - - inode->i_mode &= ~(S_ISUID | S_ISGID); - security_task_to_inode(task, inode); + pid_update_inode(task, inode); put_task_struct(task); return 1; } @@ -2438,7 +2442,7 @@ static int proc_pident_instantiate(struct inode *dir, inode = proc_pid_make_inode(dir->i_sb, task, p->mode); if (!inode) - goto out; + return -ENOENT; ei = PROC_I(inode); if (S_ISDIR(inode->i_mode)) @@ -2448,13 +2452,10 @@ static int proc_pident_instantiate(struct inode *dir, if (p->fop) inode->i_fop = p->fop; ei->op = p->op; + pid_update_inode(task, inode); d_set_d_op(dentry, &pid_dentry_operations); d_add(dentry, inode); - /* Close the race of the process dying before we return the dentry */ - if (pid_revalidate(dentry, 0)) - return 0; -out: - return -ENOENT; + return 0; } static struct dentry *proc_pident_lookup(struct inode *dir, @@ -3140,22 +3141,18 @@ static int proc_pid_instantiate(struct inode *dir, inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO); if (!inode) - goto out; + return -ENOENT; inode->i_op = &proc_tgid_base_inode_operations; inode->i_fop = &proc_tgid_base_operations; inode->i_flags|=S_IMMUTABLE; set_nlink(inode, nlink_tgid); + pid_update_inode(task, inode); d_set_d_op(dentry, &pid_dentry_operations); - d_add(dentry, inode); - /* Close the race of the process dying before we return the dentry */ - if (pid_revalidate(dentry, 0)) - return 0; -out: - return -ENOENT; + return 0; } struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags) @@ -3434,23 +3431,19 @@ static int proc_task_instantiate(struct inode *dir, { struct inode *inode; inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO); - if (!inode) - goto out; + return -ENOENT; + inode->i_op = &proc_tid_base_inode_operations; inode->i_fop = &proc_tid_base_operations; - inode->i_flags|=S_IMMUTABLE; + inode->i_flags |= S_IMMUTABLE; set_nlink(inode, nlink_tid); + pid_update_inode(task, inode); d_set_d_op(dentry, &pid_dentry_operations); - d_add(dentry, inode); - /* Close the race of the process dying before we return the dentry */ - if (pid_revalidate(dentry, 0)) - return 0; -out: - return -ENOENT; + return 0; } static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags) diff --git a/fs/proc/internal.h b/fs/proc/internal.h index 0f1692e63cb6..04a455b9ae69 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -147,7 +147,7 @@ extern const struct dentry_operations pid_dentry_operations; extern int pid_getattr(const struct path *, struct kstat *, u32, unsigned int); extern int proc_setattr(struct dentry *, struct iattr *); extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t); -extern int pid_revalidate(struct dentry *, unsigned int); +extern void pid_update_inode(struct task_struct *, struct inode *); extern int pid_delete_dentry(const struct dentry *); extern int proc_pid_readdir(struct file *, struct dir_context *); extern struct dentry *proc_pid_lookup(struct inode *, struct dentry *, unsigned int); diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c index 59b17e509f46..ad1adce6541d 100644 --- a/fs/proc/namespaces.c +++ b/fs/proc/namespaces.c @@ -96,19 +96,16 @@ static int proc_ns_instantiate(struct inode *dir, inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK | S_IRWXUGO); if (!inode) - goto out; + return -ENOENT; ei = PROC_I(inode); inode->i_op = &proc_ns_link_inode_operations; ei->ns_ops = ns_ops; + pid_update_inode(task, inode); d_set_d_op(dentry, &pid_dentry_operations); d_add(dentry, inode); - /* Close the race of the process dying before we return the dentry */ - if (pid_revalidate(dentry, 0)) - return 0; -out: - return -ENOENT; + return 0; } static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx) -- cgit v1.2.3 From 1ae9bd8b7e4912b238a14adc7c559a7ecbb9c062 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 2 May 2018 22:42:22 -0400 Subject: proc_lookupfd_common(): don't bother with instantiate unless the file is open ... and take the "check if file is open, pick ->f_mode" into a helper; tid_fd_revalidate() can use it. The next patch will get rid of tid_fd_revalidate() calls in instantiate callbacks. Signed-off-by: Al Viro --- fs/proc/fd.c | 63 ++++++++++++++++++++++++++++++++---------------------------- 1 file changed, 34 insertions(+), 29 deletions(-) (limited to 'fs/proc') diff --git a/fs/proc/fd.c b/fs/proc/fd.c index 6b80cd1e419a..d38845ecc408 100644 --- a/fs/proc/fd.c +++ b/fs/proc/fd.c @@ -81,12 +81,29 @@ static const struct file_operations proc_fdinfo_file_operations = { .release = single_release, }; +static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode) +{ + struct files_struct *files = get_files_struct(task); + struct file *file; + + if (!files) + return false; + + rcu_read_lock(); + file = fcheck_files(files, fd); + if (file) + *mode = file->f_mode; + rcu_read_unlock(); + put_files_struct(files); + return !!file; +} + static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags) { - struct files_struct *files; struct task_struct *task; struct inode *inode; unsigned int fd; + fmode_t f_mode; if (flags & LOOKUP_RCU) return -ECHILD; @@ -96,35 +113,20 @@ static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags) fd = proc_fd(inode); if (task) { - files = get_files_struct(task); - if (files) { - struct file *file; - - rcu_read_lock(); - file = fcheck_files(files, fd); - if (file) { - unsigned f_mode = file->f_mode; - - rcu_read_unlock(); - put_files_struct(files); - - task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid); - - if (S_ISLNK(inode->i_mode)) { - unsigned i_mode = S_IFLNK; - if (f_mode & FMODE_READ) - i_mode |= S_IRUSR | S_IXUSR; - if (f_mode & FMODE_WRITE) - i_mode |= S_IWUSR | S_IXUSR; - inode->i_mode = i_mode; - } - - security_task_to_inode(task, inode); - put_task_struct(task); - return 1; + if (tid_fd_mode(task, fd, &f_mode)) { + task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid); + + if (S_ISLNK(inode->i_mode)) { + unsigned i_mode = S_IFLNK; + if (f_mode & FMODE_READ) + i_mode |= S_IRUSR | S_IXUSR; + if (f_mode & FMODE_WRITE) + i_mode |= S_IWUSR | S_IXUSR; + inode->i_mode = i_mode; } - rcu_read_unlock(); - put_files_struct(files); + security_task_to_inode(task, inode); + put_task_struct(task); + return 1; } put_task_struct(task); } @@ -203,11 +205,14 @@ static struct dentry *proc_lookupfd_common(struct inode *dir, struct task_struct *task = get_proc_task(dir); int result = -ENOENT; unsigned fd = name_to_int(&dentry->d_name); + fmode_t f_mode; if (!task) goto out_no_task; if (fd == ~0U) goto out; + if (!tid_fd_mode(task, fd, &f_mode)) + goto out; result = instantiate(dir, dentry, task, (void *)(unsigned long)fd); out: -- cgit v1.2.3 From 988363864132f86d5722dddd7f765080ef271519 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 3 May 2018 09:00:33 -0400 Subject: don't bother with tid_fd_revalidate() in lookups what we want it for is actually updating inode metadata; take _that_ into a separate helper and use it. Signed-off-by: Al Viro --- fs/proc/fd.c | 81 +++++++++++++++++++++++++++++++++--------------------------- 1 file changed, 44 insertions(+), 37 deletions(-) (limited to 'fs/proc') diff --git a/fs/proc/fd.c b/fs/proc/fd.c index d38845ecc408..f5de22a9e9e0 100644 --- a/fs/proc/fd.c +++ b/fs/proc/fd.c @@ -98,12 +98,27 @@ static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode) return !!file; } +static void tid_fd_update_inode(struct task_struct *task, struct inode *inode, + fmode_t f_mode) +{ + task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid); + + if (S_ISLNK(inode->i_mode)) { + unsigned i_mode = S_IFLNK; + if (f_mode & FMODE_READ) + i_mode |= S_IRUSR | S_IXUSR; + if (f_mode & FMODE_WRITE) + i_mode |= S_IWUSR | S_IXUSR; + inode->i_mode = i_mode; + } + security_task_to_inode(task, inode); +} + static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags) { struct task_struct *task; struct inode *inode; unsigned int fd; - fmode_t f_mode; if (flags & LOOKUP_RCU) return -ECHILD; @@ -113,18 +128,9 @@ static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags) fd = proc_fd(inode); if (task) { + fmode_t f_mode; if (tid_fd_mode(task, fd, &f_mode)) { - task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid); - - if (S_ISLNK(inode->i_mode)) { - unsigned i_mode = S_IFLNK; - if (f_mode & FMODE_READ) - i_mode |= S_IRUSR | S_IXUSR; - if (f_mode & FMODE_WRITE) - i_mode |= S_IWUSR | S_IXUSR; - inode->i_mode = i_mode; - } - security_task_to_inode(task, inode); + tid_fd_update_inode(task, inode, f_mode); put_task_struct(task); return 1; } @@ -168,34 +174,35 @@ static int proc_fd_link(struct dentry *dentry, struct path *path) return ret; } +struct fd_data { + fmode_t mode; + unsigned fd; +}; + static int proc_fd_instantiate(struct inode *dir, struct dentry *dentry, struct task_struct *task, const void *ptr) { - unsigned fd = (unsigned long)ptr; + const struct fd_data *data = ptr; struct proc_inode *ei; struct inode *inode; inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK); if (!inode) - goto out; + return -ENOENT; ei = PROC_I(inode); - ei->fd = fd; + ei->fd = data->fd; inode->i_op = &proc_pid_link_inode_operations; inode->i_size = 64; ei->op.proc_get_link = proc_fd_link; + tid_fd_update_inode(task, inode, data->mode); d_set_d_op(dentry, &tid_fd_dentry_operations); d_add(dentry, inode); - - /* Close the race of the process dying before we return the dentry */ - if (tid_fd_revalidate(dentry, 0)) - return 0; - out: - return -ENOENT; + return 0; } static struct dentry *proc_lookupfd_common(struct inode *dir, @@ -204,17 +211,16 @@ static struct dentry *proc_lookupfd_common(struct inode *dir, { struct task_struct *task = get_proc_task(dir); int result = -ENOENT; - unsigned fd = name_to_int(&dentry->d_name); - fmode_t f_mode; + struct fd_data data = {.fd = name_to_int(&dentry->d_name)}; if (!task) goto out_no_task; - if (fd == ~0U) + if (data.fd == ~0U) goto out; - if (!tid_fd_mode(task, fd, &f_mode)) + if (!tid_fd_mode(task, data.fd, &data.mode)) goto out; - result = instantiate(dir, dentry, task, (void *)(unsigned long)fd); + result = instantiate(dir, dentry, task, &data); out: put_task_struct(task); out_no_task: @@ -241,17 +247,22 @@ static int proc_readfd_common(struct file *file, struct dir_context *ctx, for (fd = ctx->pos - 2; fd < files_fdtable(files)->max_fds; fd++, ctx->pos++) { + struct file *f; + struct fd_data data; char name[10 + 1]; int len; - if (!fcheck_files(files, fd)) + f = fcheck_files(files, fd); + if (!f) continue; + data.mode = f->f_mode; rcu_read_unlock(); + data.fd = fd; len = snprintf(name, sizeof(name), "%u", fd); if (!proc_fill_cache(file, ctx, name, len, instantiate, p, - (void *)(unsigned long)fd)) + &data)) goto out_fd_loop; cond_resched(); rcu_read_lock(); @@ -313,27 +324,23 @@ static int proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry, struct task_struct *task, const void *ptr) { - unsigned fd = (unsigned long)ptr; + const struct fd_data *data = ptr; struct proc_inode *ei; struct inode *inode; inode = proc_pid_make_inode(dir->i_sb, task, S_IFREG | S_IRUSR); if (!inode) - goto out; + return -ENOENT; ei = PROC_I(inode); - ei->fd = fd; + ei->fd = data->fd; inode->i_fop = &proc_fdinfo_file_operations; + tid_fd_update_inode(task, inode, 0); d_set_d_op(dentry, &tid_fd_dentry_operations); d_add(dentry, inode); - - /* Close the race of the process dying before we return the dentry */ - if (tid_fd_revalidate(dentry, 0)) - return 0; - out: - return -ENOENT; + return 0; } static struct dentry * -- cgit v1.2.3 From 0168b9e38c4213e162b15444c071d4198ff470e8 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 3 May 2018 09:21:05 -0400 Subject: procfs: switch instantiate_t to d_splice_alias() ... and get rid of pointless struct inode *dir argument of those, while we are at it. Signed-off-by: Al Viro --- fs/proc/base.c | 93 ++++++++++++++++++++++++---------------------------- fs/proc/fd.c | 30 ++++++++--------- fs/proc/internal.h | 2 +- fs/proc/namespaces.c | 19 +++++------ 4 files changed, 65 insertions(+), 79 deletions(-) (limited to 'fs/proc') diff --git a/fs/proc/base.c b/fs/proc/base.c index 6e0875505898..de22c2002b38 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1878,8 +1878,8 @@ bool proc_fill_cache(struct file *file, struct dir_context *ctx, struct dentry *child, *dir = file->f_path.dentry; struct qstr qname = QSTR_INIT(name, len); struct inode *inode; - unsigned type; - ino_t ino; + unsigned type = DT_UNKNOWN; + ino_t ino = 1; child = d_hash_and_lookup(dir, &qname); if (!child) { @@ -1888,22 +1888,23 @@ bool proc_fill_cache(struct file *file, struct dir_context *ctx, if (IS_ERR(child)) goto end_instantiate; if (d_in_lookup(child)) { - int err = instantiate(d_inode(dir), child, task, ptr); + struct dentry *res; + res = instantiate(child, task, ptr); d_lookup_done(child); - if (err < 0) { - dput(child); + if (IS_ERR(res)) goto end_instantiate; + if (unlikely(res)) { + dput(child); + child = res; } } } inode = d_inode(child); ino = inode->i_ino; type = inode->i_mode >> 12; +end_instantiate: dput(child); return dir_emit(ctx, name, len, ino, type); - -end_instantiate: - return dir_emit(ctx, name, len, 1, DT_UNKNOWN); } /* @@ -2065,19 +2066,19 @@ static const struct inode_operations proc_map_files_link_inode_operations = { .setattr = proc_setattr, }; -static int -proc_map_files_instantiate(struct inode *dir, struct dentry *dentry, +static struct dentry * +proc_map_files_instantiate(struct dentry *dentry, struct task_struct *task, const void *ptr) { fmode_t mode = (fmode_t)(unsigned long)ptr; struct proc_inode *ei; struct inode *inode; - inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK | + inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK | ((mode & FMODE_READ ) ? S_IRUSR : 0) | ((mode & FMODE_WRITE) ? S_IWUSR : 0)); if (!inode) - return -ENOENT; + return ERR_PTR(-ENOENT); ei = PROC_I(inode); ei->op.proc_get_link = map_files_get_link; @@ -2086,9 +2087,7 @@ proc_map_files_instantiate(struct inode *dir, struct dentry *dentry, inode->i_size = 64; d_set_d_op(dentry, &tid_map_files_dentry_operations); - d_add(dentry, inode); - - return 0; + return d_splice_alias(inode, dentry); } static struct dentry *proc_map_files_lookup(struct inode *dir, @@ -2097,19 +2096,19 @@ static struct dentry *proc_map_files_lookup(struct inode *dir, unsigned long vm_start, vm_end; struct vm_area_struct *vma; struct task_struct *task; - int result; + struct dentry *result; struct mm_struct *mm; - result = -ENOENT; + result = ERR_PTR(-ENOENT); task = get_proc_task(dir); if (!task) goto out; - result = -EACCES; + result = ERR_PTR(-EACCES); if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) goto out_put_task; - result = -ENOENT; + result = ERR_PTR(-ENOENT); if (dname_to_vma_addr(dentry, &vm_start, &vm_end)) goto out_put_task; @@ -2123,7 +2122,7 @@ static struct dentry *proc_map_files_lookup(struct inode *dir, goto out_no_vma; if (vma->vm_file) - result = proc_map_files_instantiate(dir, dentry, task, + result = proc_map_files_instantiate(dentry, task, (void *)(unsigned long)vma->vm_file->f_mode); out_no_vma: @@ -2132,7 +2131,7 @@ out_no_vma: out_put_task: put_task_struct(task); out: - return ERR_PTR(result); + return result; } static const struct inode_operations proc_map_files_inode_operations = { @@ -2433,16 +2432,16 @@ static const struct file_operations proc_pid_set_timerslack_ns_operations = { .release = single_release, }; -static int proc_pident_instantiate(struct inode *dir, - struct dentry *dentry, struct task_struct *task, const void *ptr) +static struct dentry *proc_pident_instantiate(struct dentry *dentry, + struct task_struct *task, const void *ptr) { const struct pid_entry *p = ptr; struct inode *inode; struct proc_inode *ei; - inode = proc_pid_make_inode(dir->i_sb, task, p->mode); + inode = proc_pid_make_inode(dentry->d_sb, task, p->mode); if (!inode) - return -ENOENT; + return ERR_PTR(-ENOENT); ei = PROC_I(inode); if (S_ISDIR(inode->i_mode)) @@ -2454,8 +2453,7 @@ static int proc_pident_instantiate(struct inode *dir, ei->op = p->op; pid_update_inode(task, inode); d_set_d_op(dentry, &pid_dentry_operations); - d_add(dentry, inode); - return 0; + return d_splice_alias(inode, dentry); } static struct dentry *proc_pident_lookup(struct inode *dir, @@ -2463,11 +2461,9 @@ static struct dentry *proc_pident_lookup(struct inode *dir, const struct pid_entry *ents, unsigned int nents) { - int error; struct task_struct *task = get_proc_task(dir); const struct pid_entry *p, *last; - - error = -ENOENT; + struct dentry *res = ERR_PTR(-ENOENT); if (!task) goto out_no_task; @@ -2486,11 +2482,11 @@ static struct dentry *proc_pident_lookup(struct inode *dir, if (p >= last) goto out; - error = proc_pident_instantiate(dir, dentry, task, p); + res = proc_pident_instantiate(dentry, task, p); out: put_task_struct(task); out_no_task: - return ERR_PTR(error); + return res; } static int proc_pident_readdir(struct file *file, struct dir_context *ctx, @@ -3133,15 +3129,14 @@ void proc_flush_task(struct task_struct *task) } } -static int proc_pid_instantiate(struct inode *dir, - struct dentry * dentry, +static struct dentry *proc_pid_instantiate(struct dentry * dentry, struct task_struct *task, const void *ptr) { struct inode *inode; - inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO); + inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO); if (!inode) - return -ENOENT; + return ERR_PTR(-ENOENT); inode->i_op = &proc_tgid_base_inode_operations; inode->i_fop = &proc_tgid_base_operations; @@ -3151,16 +3146,15 @@ static int proc_pid_instantiate(struct inode *dir, pid_update_inode(task, inode); d_set_d_op(dentry, &pid_dentry_operations); - d_add(dentry, inode); - return 0; + return d_splice_alias(inode, dentry); } struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags) { - int result = -ENOENT; struct task_struct *task; unsigned tgid; struct pid_namespace *ns; + struct dentry *result = ERR_PTR(-ENOENT); tgid = name_to_int(&dentry->d_name); if (tgid == ~0U) @@ -3175,10 +3169,10 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsign if (!task) goto out; - result = proc_pid_instantiate(dir, dentry, task, NULL); + result = proc_pid_instantiate(dentry, task, NULL); put_task_struct(task); out: - return ERR_PTR(result); + return result; } /* @@ -3426,13 +3420,13 @@ static const struct inode_operations proc_tid_base_inode_operations = { .setattr = proc_setattr, }; -static int proc_task_instantiate(struct inode *dir, - struct dentry *dentry, struct task_struct *task, const void *ptr) +static struct dentry *proc_task_instantiate(struct dentry *dentry, + struct task_struct *task, const void *ptr) { struct inode *inode; - inode = proc_pid_make_inode(dir->i_sb, task, S_IFDIR | S_IRUGO | S_IXUGO); + inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO); if (!inode) - return -ENOENT; + return ERR_PTR(-ENOENT); inode->i_op = &proc_tid_base_inode_operations; inode->i_fop = &proc_tid_base_operations; @@ -3442,17 +3436,16 @@ static int proc_task_instantiate(struct inode *dir, pid_update_inode(task, inode); d_set_d_op(dentry, &pid_dentry_operations); - d_add(dentry, inode); - return 0; + return d_splice_alias(inode, dentry); } static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags) { - int result = -ENOENT; struct task_struct *task; struct task_struct *leader = get_proc_task(dir); unsigned tid; struct pid_namespace *ns; + struct dentry *result = ERR_PTR(-ENOENT); if (!leader) goto out_no_task; @@ -3472,13 +3465,13 @@ static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry if (!same_thread_group(leader, task)) goto out_drop_task; - result = proc_task_instantiate(dir, dentry, task, NULL); + result = proc_task_instantiate(dentry, task, NULL); out_drop_task: put_task_struct(task); out: put_task_struct(leader); out_no_task: - return ERR_PTR(result); + return result; } /* diff --git a/fs/proc/fd.c b/fs/proc/fd.c index f5de22a9e9e0..05b9893e9a22 100644 --- a/fs/proc/fd.c +++ b/fs/proc/fd.c @@ -179,17 +179,16 @@ struct fd_data { unsigned fd; }; -static int -proc_fd_instantiate(struct inode *dir, struct dentry *dentry, - struct task_struct *task, const void *ptr) +static struct dentry *proc_fd_instantiate(struct dentry *dentry, + struct task_struct *task, const void *ptr) { const struct fd_data *data = ptr; struct proc_inode *ei; struct inode *inode; - inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK); + inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK); if (!inode) - return -ENOENT; + return ERR_PTR(-ENOENT); ei = PROC_I(inode); ei->fd = data->fd; @@ -201,8 +200,7 @@ proc_fd_instantiate(struct inode *dir, struct dentry *dentry, tid_fd_update_inode(task, inode, data->mode); d_set_d_op(dentry, &tid_fd_dentry_operations); - d_add(dentry, inode); - return 0; + return d_splice_alias(inode, dentry); } static struct dentry *proc_lookupfd_common(struct inode *dir, @@ -210,8 +208,8 @@ static struct dentry *proc_lookupfd_common(struct inode *dir, instantiate_t instantiate) { struct task_struct *task = get_proc_task(dir); - int result = -ENOENT; struct fd_data data = {.fd = name_to_int(&dentry->d_name)}; + struct dentry *result = ERR_PTR(-ENOENT); if (!task) goto out_no_task; @@ -220,11 +218,11 @@ static struct dentry *proc_lookupfd_common(struct inode *dir, if (!tid_fd_mode(task, data.fd, &data.mode)) goto out; - result = instantiate(dir, dentry, task, &data); + result = instantiate(dentry, task, &data); out: put_task_struct(task); out_no_task: - return ERR_PTR(result); + return result; } static int proc_readfd_common(struct file *file, struct dir_context *ctx, @@ -320,17 +318,16 @@ const struct inode_operations proc_fd_inode_operations = { .setattr = proc_setattr, }; -static int -proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry, - struct task_struct *task, const void *ptr) +static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry, + struct task_struct *task, const void *ptr) { const struct fd_data *data = ptr; struct proc_inode *ei; struct inode *inode; - inode = proc_pid_make_inode(dir->i_sb, task, S_IFREG | S_IRUSR); + inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUSR); if (!inode) - return -ENOENT; + return ERR_PTR(-ENOENT); ei = PROC_I(inode); ei->fd = data->fd; @@ -339,8 +336,7 @@ proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry, tid_fd_update_inode(task, inode, 0); d_set_d_op(dentry, &tid_fd_dentry_operations); - d_add(dentry, inode); - return 0; + return d_splice_alias(inode, dentry); } static struct dentry * diff --git a/fs/proc/internal.h b/fs/proc/internal.h index 04a455b9ae69..275b062e58af 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -154,7 +154,7 @@ extern struct dentry *proc_pid_lookup(struct inode *, struct dentry *, unsigned extern loff_t mem_lseek(struct file *, loff_t, int); /* Lookups */ -typedef int instantiate_t(struct inode *, struct dentry *, +typedef struct dentry *instantiate_t(struct dentry *, struct task_struct *, const void *); extern bool proc_fill_cache(struct file *, struct dir_context *, const char *, int, instantiate_t, struct task_struct *, const void *); diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c index ad1adce6541d..dd2b35f78b09 100644 --- a/fs/proc/namespaces.c +++ b/fs/proc/namespaces.c @@ -87,16 +87,16 @@ static const struct inode_operations proc_ns_link_inode_operations = { .setattr = proc_setattr, }; -static int proc_ns_instantiate(struct inode *dir, - struct dentry *dentry, struct task_struct *task, const void *ptr) +static struct dentry *proc_ns_instantiate(struct dentry *dentry, + struct task_struct *task, const void *ptr) { const struct proc_ns_operations *ns_ops = ptr; struct inode *inode; struct proc_inode *ei; - inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK | S_IRWXUGO); + inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK | S_IRWXUGO); if (!inode) - return -ENOENT; + return ERR_PTR(-ENOENT); ei = PROC_I(inode); inode->i_op = &proc_ns_link_inode_operations; @@ -104,8 +104,7 @@ static int proc_ns_instantiate(struct inode *dir, pid_update_inode(task, inode); d_set_d_op(dentry, &pid_dentry_operations); - d_add(dentry, inode); - return 0; + return d_splice_alias(inode, dentry); } static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx) @@ -144,12 +143,10 @@ const struct file_operations proc_ns_dir_operations = { static struct dentry *proc_ns_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { - int error; struct task_struct *task = get_proc_task(dir); const struct proc_ns_operations **entry, **last; unsigned int len = dentry->d_name.len; - - error = -ENOENT; + struct dentry *res = ERR_PTR(-ENOENT); if (!task) goto out_no_task; @@ -164,11 +161,11 @@ static struct dentry *proc_ns_dir_lookup(struct inode *dir, if (entry == last) goto out; - error = proc_ns_instantiate(dir, dentry, task, *entry); + res = proc_ns_instantiate(dentry, task, *entry); out: put_task_struct(task); out_no_task: - return ERR_PTR(error); + return res; } const struct inode_operations proc_ns_dir_inode_operations = { -- cgit v1.2.3 From 888e2b03ef56694290e58bd9ac23f8033bf6369f Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 3 May 2018 09:45:06 -0400 Subject: switch the rest of procfs lookups to d_splice_alias() Signed-off-by: Al Viro --- fs/proc/generic.c | 3 +-- fs/proc/proc_sysctl.c | 15 ++++++++++++--- 2 files changed, 13 insertions(+), 5 deletions(-) (limited to 'fs/proc') diff --git a/fs/proc/generic.c b/fs/proc/generic.c index 2078e70e1595..b77034a694ef 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -256,8 +256,7 @@ struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry, if (!inode) return ERR_PTR(-ENOMEM); d_set_d_op(dentry, &proc_misc_dentry_ops); - d_add(dentry, inode); - return NULL; + return d_splice_alias(inode, dentry); } read_unlock(&proc_subdir_lock); return ERR_PTR(-ENOENT); diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 8989936f2995..4d765e5e91ed 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -554,9 +554,8 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, if (!inode) goto out; - err = NULL; d_set_d_op(dentry, &proc_sys_dentry_operations); - d_add(dentry, inode); + err = d_splice_alias(inode, dentry); out: if (h) @@ -684,6 +683,7 @@ static bool proc_sys_fill_cache(struct file *file, if (IS_ERR(child)) return false; if (d_in_lookup(child)) { + struct dentry *res; inode = proc_sys_make_inode(dir->d_sb, head, table); if (!inode) { d_lookup_done(child); @@ -691,7 +691,16 @@ static bool proc_sys_fill_cache(struct file *file, return false; } d_set_d_op(child, &proc_sys_dentry_operations); - d_add(child, inode); + res = d_splice_alias(inode, child); + d_lookup_done(child); + if (unlikely(res)) { + if (IS_ERR(res)) { + dput(child); + return false; + } + dput(child); + child = res; + } } } inode = d_inode(child); -- cgit v1.2.3