FAILED: patch "[PATCH] proc: protect ptrace_may_access() with exec_update_lock (FD" failed to apply to 6.18-stable tree

PATCH New [email protected] 2 participants 3 messages Jul 14 – Jul 16

Subsystems (2)

Stable branch Proc filesystem

lore

Share & tools

lore

[email protected]

author maintainer

2026-07-14 14:50 UTC #0 lore raw

The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 6255da28d4bb5349fe18e84cb043ccd394eba75d
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026071446-art-flip-74fe@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6255da28d4bb5349fe18e84cb043ccd394eba75d Mon Sep 17 00:00:00 2001
From: Jann Horn <[email protected]>
Date: Mon, 18 May 2026 18:35:16 +0200
Subject: [PATCH] proc: protect ptrace_may_access() with exec_update_lock (FD
links)

proc_pid_get_link() and proc_pid_readlink() currently look up the task from the pid once, then do the ptrace access check on that task, then look up the task from the pid a second time to do the actual access. That's racy in several ways.

To fix it, pass the task to the ->proc_get_link() handler, and instead of proc_fd_access_allowed(), introduce a new helper call_proc_get_link() that looks up and locks the task, does the access check, and calls ->proc_get_link().

Fixes 778c1144771f ("[PATCH] proc: Use sane permission checks on the /proc/<pid>/fd/ symlinks")

Cc [email protected]

Signed-off-by Jann Horn <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Christian Brauner (Amutable) <[email protected]>

fs/proc/base.c +47 ~~-72~~

index cc99d953a0a3..5042f14d24f3 100644
@@ -218,33 +218,24 @@ static int get_task_root(struct task_struct *task, struct path *root)
 	return result;
 }
 
-static int proc_cwd_link(struct dentry *dentry, struct path *path)
+static int proc_cwd_link(struct dentry *dentry, struct path *path,
+			 struct task_struct *task)
 {
-	struct task_struct *task = get_proc_task(d_inode(dentry));
 	int result = -ENOENT;
 
-	if (task) {
-		task_lock(task);
-		if (task->fs) {
-			get_fs_pwd(task->fs, path);
-			result = 0;
-		}
-		task_unlock(task);
-		put_task_struct(task);
+	task_lock(task);
+	if (task->fs) {
+		get_fs_pwd(task->fs, path);
+		result = 0;
 	}
+	task_unlock(task);
 	return result;
 }
 
-static int proc_root_link(struct dentry *dentry, struct path *path)
+static int proc_root_link(struct dentry *dentry, struct path *path,
+			  struct task_struct *task)
 {
-	struct task_struct *task = get_proc_task(d_inode(dentry));
-	int result = -ENOENT;
-
-	if (task) {
-		result = get_task_root(task, path);
-		put_task_struct(task);
-	}
-	return result;
+	return get_task_root(task, path);
 }
 
 /*

@@ -710,23 +701,6 @@ static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 /*                       Here the fs part begins                        */
 /************************************************************************/
 
-/* permission checks */
-static bool proc_fd_access_allowed(struct inode *inode)
-{
-	struct task_struct *task;
-	bool allowed = false;
-	/* Allow access to a task's file descriptors if it is us or we
-	 * may use ptrace attach to the process and find out that
-	 * information.
-	 */
-	task = get_proc_task(inode);
-	if (task) {
-		allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
-		put_task_struct(task);
-	}
-	return allowed;
-}
-
 int proc_nochmod_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *attr)
 {

@@ -1783,16 +1757,12 @@ static const struct file_operations proc_pid_set_comm_operations = {
 	.release	= single_release,
 };
 
-static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
+static int proc_exe_link(struct dentry *dentry, struct path *exe_path,
+			 struct task_struct *task)
 {
-	struct task_struct *task;
 	struct file *exe_file;
 
-	task = get_proc_task(d_inode(dentry));
-	if (!task)
-		return -ENOENT;
 	exe_file = get_task_exe_file(task);
-	put_task_struct(task);
 	if (exe_file) {
 		*exe_path = exe_file->f_path;
 		path_get(&exe_file->f_path);

@@ -1802,26 +1772,42 @@ static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
 		return -ENOENT;
 }
 
+static int call_proc_get_link(struct dentry *dentry, struct inode *inode, struct path *path_out)
+{
+	struct task_struct *task;
+	int ret;
+
+	task = get_proc_task(inode);
+	if (!task)
+		return -ENOENT;
+	ret = down_read_killable(&task->signal->exec_update_lock);
+	if (ret)
+		goto out_put_task;
+	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
+		ret = -EACCES;
+		goto out;
+	}
+	ret = PROC_I(inode)->op.proc_get_link(dentry, path_out, task);
+
+out:
+	up_read(&task->signal->exec_update_lock);
+out_put_task:
+	put_task_struct(task);
+	return ret;
+}
+
 static const char *proc_pid_get_link(struct dentry *dentry,
 				     struct inode *inode,
 				     struct delayed_call *done)
 {
 	struct path path;
-	int error = -EACCES;
+	int error;
 
 	if (!dentry)
 		return ERR_PTR(-ECHILD);
-
-	/* Are we allowed to snoop on the tasks file descriptors? */
-	if (!proc_fd_access_allowed(inode))
-		goto out;
-
-	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
-	if (error)
-		goto out;
-
-	error = nd_jump_link(&path);
-out:
+	error = call_proc_get_link(dentry, inode, &path);
+	if (!error)
+		error = nd_jump_link(&path);
 	return ERR_PTR(error);
 }

@@ -1855,17 +1841,11 @@ static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int b
 	struct inode *inode = d_inode(dentry);
 	struct path path;
 
-	/* Are we allowed to snoop on the tasks file descriptors? */
-	if (!proc_fd_access_allowed(inode))
-		goto out;
-
-	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
-	if (error)
-		goto out;
-
-	error = do_proc_readlink(&path, buffer, buflen);
-	path_put(&path);
-out:
+	error = call_proc_get_link(dentry, inode, &path);
+	if (!error) {
+		error = do_proc_readlink(&path, buffer, buflen);
+		path_put(&path);
+	}
 	return error;
 }

@@ -2256,21 +2236,16 @@ static const struct dentry_operations tid_map_files_dentry_operations = {
 	.d_delete	= pid_delete_dentry,
 };
 
-static int map_files_get_link(struct dentry *dentry, struct path *path)
+static int map_files_get_link(struct dentry *dentry, struct path *path,
+			      struct task_struct *task)
 {
 	unsigned long vm_start, vm_end;
 	struct vm_area_struct *vma;
-	struct task_struct *task;
 	struct mm_struct *mm;
 	int rc;
 
 	rc = -ENOENT;
-	task = get_proc_task(d_inode(dentry));
-	if (!task)
-		goto out;
-
 	mm = get_task_mm(task);
-	put_task_struct(task);
 	if (!mm)
 		goto out;

fs/proc/fd.c +10 ~~-15~~

index 05c7513e77c7..0f9a1556f2a3 100644
@@ -171,24 +171,19 @@ static const struct dentry_operations tid_fd_dentry_operations = {
 	.d_delete	= pid_delete_dentry,
 };
 
-static int proc_fd_link(struct dentry *dentry, struct path *path)
+static int proc_fd_link(struct dentry *dentry, struct path *path,
+			struct task_struct *task)
 {
-	struct task_struct *task;
 	int ret = -ENOENT;
+	unsigned int fd = proc_fd(d_inode(dentry));
+	struct file *fd_file;
 
-	task = get_proc_task(d_inode(dentry));
-	if (task) {
-		unsigned int fd = proc_fd(d_inode(dentry));
-		struct file *fd_file;
-
-		fd_file = fget_task(task, fd);
-		if (fd_file) {
-			*path = fd_file->f_path;
-			path_get(&fd_file->f_path);
-			ret = 0;
-			fput(fd_file);
-		}
-		put_task_struct(task);
+	fd_file = fget_task(task, fd);
+	if (fd_file) {
+		*path = fd_file->f_path;
+		path_get(&fd_file->f_path);
+		ret = 0;
+		fput(fd_file);
 	}
 
 	return ret;

fs/proc/internal.h +1 -1

index 1edbabbdbc5d..b232e1098117 100644
@@ -110,7 +110,7 @@ extern struct kmem_cache *proc_dir_entry_cache;
 void pde_free(struct proc_dir_entry *pde);
 
 union proc_op {
-	int (*proc_get_link)(struct dentry *, struct path *);
+	int (*proc_get_link)(struct dentry *, struct path *, struct task_struct *);
 	int (*proc_show)(struct seq_file *m,
 		struct pid_namespace *ns, struct pid *pid,
 		struct task_struct *task);

Sasha Levin

maintainer

2026-07-16 16:45 UTC #1 lore raw

PATCH 1/2 proc: rename proc_setattr to proc_nochmod_setattr

From: Christoph Hellwig <[email protected]>

[ Upstream commit 690005b0b1e6b567c88b7790e6d90d4d6c9e09cc ]

What is currently proc_setattr is a special version added after the more general procfs ->seattr in commit 6d76fa58b050 ("Don't allow chmod() on the /proc/<pid>/ files"). Give it a name that reflects that to free the proc_setattr name and better describe what is doing.

Signed-off-by Christoph Hellwig <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Reviewed-by Jan Kara <[email protected]>

Signed-off-by Christian Brauner <[email protected]>

Stable-dep-of: 6255da28d4bb ("proc: protect ptrace_may_access() with exec_update_lock (FD links)")

Signed-off-by Sasha Levin <[email protected]>

---
 fs/proc/base.c       | 22 +++++++++++-----------
 fs/proc/fd.c         |  6 +++---
 fs/proc/internal.h   |  4 ++--
 fs/proc/namespaces.c |  4 ++--
 fs/proc/proc_net.c   |  2 +-
 5 files changed, 19 insertions(+), 19 deletions(-)

fs/proc/base.c +11 ~~-11~~

index a314fd9af17c08..998c6cce77c192 100644
@@ -721,7 +721,7 @@ static bool proc_fd_access_allowed(struct inode *inode)
 	return allowed;
 }
 
-int proc_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+int proc_nochmod_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *attr)
 {
 	int error;

@@ -794,7 +794,7 @@ static int proc_pid_permission(struct mnt_idmap *idmap,
 
 
 static const struct inode_operations proc_def_inode_operations = {
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 };
 
 static int proc_single_show(struct seq_file *m, void *v)

@@ -1866,7 +1866,7 @@ static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int b
 const struct inode_operations proc_pid_link_inode_operations = {
 	.readlink	= proc_pid_readlink,
 	.get_link	= proc_pid_get_link,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 };

@@ -2319,7 +2319,7 @@ proc_map_files_get_link(struct dentry *dentry,
 static const struct inode_operations proc_map_files_link_inode_operations = {
 	.readlink	= proc_pid_readlink,
 	.get_link	= proc_map_files_get_link,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 };
 
 static struct dentry *

@@ -2398,7 +2398,7 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
 static const struct inode_operations proc_map_files_inode_operations = {
 	.lookup		= proc_map_files_lookup,
 	.permission	= proc_fd_permission,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 };
 
 static int

@@ -2885,7 +2885,7 @@ static struct dentry *proc_##LSM##_attr_dir_lookup(struct inode *dir, \
 static const struct inode_operations proc_##LSM##_attr_dir_inode_ops = { \
 	.lookup		= proc_##LSM##_attr_dir_lookup, \
 	.getattr	= pid_getattr, \
-	.setattr	= proc_setattr, \
+	.setattr	= proc_nochmod_setattr, \
 }
 
 #ifdef CONFIG_SECURITY_SMACK

@@ -2944,7 +2944,7 @@ static struct dentry *proc_attr_dir_lookup(struct inode *dir,
 static const struct inode_operations proc_attr_dir_inode_operations = {
 	.lookup		= proc_attr_dir_lookup,
 	.getattr	= pid_getattr,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 };
 
 #endif

@@ -3460,7 +3460,7 @@ static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *de
 static const struct inode_operations proc_tgid_base_inode_operations = {
 	.lookup		= proc_tgid_base_lookup,
 	.getattr	= pid_getattr,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 	.permission	= proc_pid_permission,
 };

@@ -3659,7 +3659,7 @@ static int proc_tid_comm_permission(struct mnt_idmap *idmap,
 }
 
 static const struct inode_operations proc_tid_comm_inode_operations = {
-		.setattr	= proc_setattr,
+		.setattr	= proc_nochmod_setattr,
 		.permission	= proc_tid_comm_permission,
 };

@@ -3788,7 +3788,7 @@ static const struct file_operations proc_tid_base_operations = {
 static const struct inode_operations proc_tid_base_inode_operations = {
 	.lookup		= proc_tid_base_lookup,
 	.getattr	= pid_getattr,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 };
 
 static struct dentry *proc_task_instantiate(struct dentry *dentry,

@@ -4001,7 +4001,7 @@ static loff_t proc_dir_llseek(struct file *file, loff_t offset, int whence)
 static const struct inode_operations proc_task_inode_operations = {
 	.lookup		= proc_task_lookup,
 	.getattr	= proc_task_getattr,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 	.permission	= proc_pid_permission,
 };

fs/proc/fd.c +3 -3

index 9eeccff49b2abf..8a48ff4a19ecb3 100644
@@ -102,7 +102,7 @@ static int proc_fdinfo_permission(struct mnt_idmap *idmap, struct inode *inode,
 
 static const struct inode_operations proc_fdinfo_file_inode_operations = {
 	.permission	= proc_fdinfo_permission,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 };
 
 static const struct file_operations proc_fdinfo_file_operations = {

@@ -361,7 +361,7 @@ const struct inode_operations proc_fd_inode_operations = {
 	.lookup		= proc_lookupfd,
 	.permission	= proc_fd_permission,
 	.getattr	= proc_fd_getattr,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 };
 
 static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry,

@@ -402,7 +402,7 @@ static int proc_fdinfo_iterate(struct file *file, struct dir_context *ctx)
 const struct inode_operations proc_fdinfo_inode_operations = {
 	.lookup		= proc_lookupfdinfo,
 	.permission	= proc_fdinfo_permission,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 };
 
 const struct file_operations proc_fdinfo_operations = {

fs/proc/internal.h +2 -2

index d1598576506c1e..2807306004e5e6 100644
@@ -257,8 +257,8 @@ extern int proc_pid_statm(struct seq_file *, struct pid_namespace *,
 extern const struct dentry_operations pid_dentry_operations;
 extern int pid_getattr(struct mnt_idmap *, const struct path *,
 		       struct kstat *, u32, unsigned int);
-extern int proc_setattr(struct mnt_idmap *, struct dentry *,
-			struct iattr *);
+int proc_nochmod_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+			struct iattr *attr);
 extern void proc_pid_evict_inode(struct proc_inode *);
 extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t);
 extern void pid_update_inode(struct task_struct *, struct inode *);

fs/proc/namespaces.c +2 -2

index ea2b597fd92cdb..39f4169f669f63 100644
@@ -92,7 +92,7 @@ static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int bufl
 static const struct inode_operations proc_ns_link_inode_operations = {
 	.readlink	= proc_ns_readlink,
 	.get_link	= proc_ns_get_link,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 };
 
 static struct dentry *proc_ns_instantiate(struct dentry *dentry,

@@ -178,5 +178,5 @@ static struct dentry *proc_ns_dir_lookup(struct inode *dir,
 const struct inode_operations proc_ns_dir_inode_operations = {
 	.lookup		= proc_ns_dir_lookup,
 	.getattr	= pid_getattr,
-	.setattr	= proc_setattr,
+	.setattr	= proc_nochmod_setattr,
 };

fs/proc/proc_net.c +1 -1

index 52f0b75cbce2ca..184cddeb8215cb 100644
@@ -322,7 +322,7 @@ static int proc_tgid_net_getattr(struct mnt_idmap *idmap,
 const struct inode_operations proc_net_inode_operations = {
 	.lookup		= proc_tgid_net_lookup,
 	.getattr	= proc_tgid_net_getattr,
-	.setattr        = proc_setattr,
+	.setattr        = proc_nochmod_setattr,
 };
 
 static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)

Signature · 1 line

2.53.0

Sasha Levin

maintainer

2026-07-16 16:45 UTC #2 lore raw

PATCH 2/2 proc: protect ptrace_may_access() with exec_update_lock (FD links)

From: Jann Horn <[email protected]>

[ Upstream commit 6255da28d4bb5349fe18e84cb043ccd394eba75d ]

Fixes 778c1144771f ("[PATCH] proc: Use sane permission checks on the /proc/<pid>/fd/ symlinks")

Cc [email protected]

Signed-off-by Jann Horn <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Christian Brauner (Amutable) <[email protected]>

Signed-off-by Sasha Levin <[email protected]>

---
 fs/proc/base.c     | 119 ++++++++++++++++++---------------------------
 fs/proc/fd.c       |  27 +++++-----
 fs/proc/internal.h |   2 +-
 3 files changed, 59 insertions(+), 89 deletions(-)

fs/proc/base.c +47 ~~-72~~

index 998c6cce77c192..9e1c4c7fd6913c 100644
@@ -218,33 +218,24 @@ static int get_task_root(struct task_struct *task, struct path *root)
 	return result;
 }
 
-static int proc_cwd_link(struct dentry *dentry, struct path *path)
+static int proc_cwd_link(struct dentry *dentry, struct path *path,
+			 struct task_struct *task)
 {
-	struct task_struct *task = get_proc_task(d_inode(dentry));
 	int result = -ENOENT;
 
-	if (task) {
-		task_lock(task);
-		if (task->fs) {
-			get_fs_pwd(task->fs, path);
-			result = 0;
-		}
-		task_unlock(task);
-		put_task_struct(task);
+	task_lock(task);
+	if (task->fs) {
+		get_fs_pwd(task->fs, path);
+		result = 0;
 	}
+	task_unlock(task);
 	return result;
 }
 
-static int proc_root_link(struct dentry *dentry, struct path *path)
+static int proc_root_link(struct dentry *dentry, struct path *path,
+			  struct task_struct *task)
 {
-	struct task_struct *task = get_proc_task(d_inode(dentry));
-	int result = -ENOENT;
-
-	if (task) {
-		result = get_task_root(task, path);
-		put_task_struct(task);
-	}
-	return result;
+	return get_task_root(task, path);
 }
 
 /*

@@ -704,23 +695,6 @@ static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 /*                       Here the fs part begins                        */
 /************************************************************************/
 
-/* permission checks */
-static bool proc_fd_access_allowed(struct inode *inode)
-{
-	struct task_struct *task;
-	bool allowed = false;
-	/* Allow access to a task's file descriptors if it is us or we
-	 * may use ptrace attach to the process and find out that
-	 * information.
-	 */
-	task = get_proc_task(inode);
-	if (task) {
-		allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
-		put_task_struct(task);
-	}
-	return allowed;
-}
-
 int proc_nochmod_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct iattr *attr)
 {

@@ -1777,16 +1751,12 @@ static const struct file_operations proc_pid_set_comm_operations = {
 	.release	= single_release,
 };
 
-static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
+static int proc_exe_link(struct dentry *dentry, struct path *exe_path,
+			 struct task_struct *task)
 {
-	struct task_struct *task;
 	struct file *exe_file;
 
-	task = get_proc_task(d_inode(dentry));
-	if (!task)
-		return -ENOENT;
 	exe_file = get_task_exe_file(task);
-	put_task_struct(task);
 	if (exe_file) {
 		*exe_path = exe_file->f_path;
 		path_get(&exe_file->f_path);

@@ -1796,26 +1766,42 @@ static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
 		return -ENOENT;
 }
 
+static int call_proc_get_link(struct dentry *dentry, struct inode *inode, struct path *path_out)
+{
+	struct task_struct *task;
+	int ret;
+
+	task = get_proc_task(inode);
+	if (!task)
+		return -ENOENT;
+	ret = down_read_killable(&task->signal->exec_update_lock);
+	if (ret)
+		goto out_put_task;
+	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
+		ret = -EACCES;
+		goto out;
+	}
+	ret = PROC_I(inode)->op.proc_get_link(dentry, path_out, task);
+
+out:
+	up_read(&task->signal->exec_update_lock);
+out_put_task:
+	put_task_struct(task);
+	return ret;
+}
+
 static const char *proc_pid_get_link(struct dentry *dentry,
 				     struct inode *inode,
 				     struct delayed_call *done)
 {
 	struct path path;
-	int error = -EACCES;
+	int error;
 
 	if (!dentry)
 		return ERR_PTR(-ECHILD);
-
-	/* Are we allowed to snoop on the tasks file descriptors? */
-	if (!proc_fd_access_allowed(inode))
-		goto out;
-
-	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
-	if (error)
-		goto out;
-
-	error = nd_jump_link(&path);
-out:
+	error = call_proc_get_link(dentry, inode, &path);
+	if (!error)
+		error = nd_jump_link(&path);
 	return ERR_PTR(error);
 }

@@ -1849,17 +1835,11 @@ static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int b
 	struct inode *inode = d_inode(dentry);
 	struct path path;
 
-	/* Are we allowed to snoop on the tasks file descriptors? */
-	if (!proc_fd_access_allowed(inode))
-		goto out;
-
-	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
-	if (error)
-		goto out;
-
-	error = do_proc_readlink(&path, buffer, buflen);
-	path_put(&path);
-out:
+	error = call_proc_get_link(dentry, inode, &path);
+	if (!error) {
+		error = do_proc_readlink(&path, buffer, buflen);
+		path_put(&path);
+	}
 	return error;
 }

@@ -2250,21 +2230,16 @@ static const struct dentry_operations tid_map_files_dentry_operations = {
 	.d_delete	= pid_delete_dentry,
 };
 
-static int map_files_get_link(struct dentry *dentry, struct path *path)
+static int map_files_get_link(struct dentry *dentry, struct path *path,
+			      struct task_struct *task)
 {
 	unsigned long vm_start, vm_end;
 	struct vm_area_struct *vma;
-	struct task_struct *task;
 	struct mm_struct *mm;
 	int rc;
 
 	rc = -ENOENT;
-	task = get_proc_task(d_inode(dentry));
-	if (!task)
-		goto out;
-
 	mm = get_task_mm(task);
-	put_task_struct(task);
 	if (!mm)
 		goto out;

fs/proc/fd.c +11 ~~-16~~

index 8a48ff4a19ecb3..5d6dac7fd1c8e7 100644
@@ -171,24 +171,19 @@ static const struct dentry_operations tid_fd_dentry_operations = {
 	.d_delete	= pid_delete_dentry,
 };
 
-static int proc_fd_link(struct dentry *dentry, struct path *path)
+static int proc_fd_link(struct dentry *dentry, struct path *path,
+			struct task_struct *task)
 {
-	struct task_struct *task;
 	int ret = -ENOENT;
-
-	task = get_proc_task(d_inode(dentry));
-	if (task) {
-		unsigned int fd = proc_fd(d_inode(dentry));
-		struct file *fd_file;
-
-		fd_file = fget_task(task, fd);
-		if (fd_file) {
-			*path = fd_file->f_path;
-			path_get(&fd_file->f_path);
-			ret = 0;
-			fput(fd_file);
-		}
-		put_task_struct(task);
+	unsigned int fd = proc_fd(d_inode(dentry));
+	struct file *fd_file;
+
+	fd_file = fget_task(task, fd);
+	if (fd_file) {
+		*path = fd_file->f_path;
+		path_get(&fd_file->f_path);
+		ret = 0;
+		fput(fd_file);
 	}
 
 	return ret;

fs/proc/internal.h +1 -1

index 2807306004e5e6..77c347d3b6ad22 100644
@@ -107,7 +107,7 @@ extern struct kmem_cache *proc_dir_entry_cache;
 void pde_free(struct proc_dir_entry *pde);
 
 union proc_op {
-	int (*proc_get_link)(struct dentry *, struct path *);
+	int (*proc_get_link)(struct dentry *, struct path *, struct task_struct *);
 	int (*proc_show)(struct seq_file *m,
 		struct pid_namespace *ns, struct pid *pid,
 		struct task_struct *task);

Signature · 1 line

2.53.0