linux-kernel - [PATCH v2 3/3] sysctl: drop now unnecessary out-of-bounds check

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Message-Id: <20240322-sysctl-empty-dir-v2-3-e559cf8ec7c0@weissschuh.net>
Date: Fri, 22 Mar 2024 18:05:58 +0100
From: Thomas Weißschuh <linux@...ssschuh.net>
To: "Eric W. Biederman" <ebiederm@...ssion.com>, 
 Luis Chamberlain <mcgrof@...nel.org>, Kees Cook <keescook@...omium.org>, 
 Joel Granados <j.granados@...sung.com>
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org, 
 Thomas Weißschuh <linux@...ssschuh.net>
Subject: [PATCH v2 3/3] sysctl: drop now unnecessary out-of-bounds check

Remove the now unneeded check for ctl_table_size; it is safe
to do so as sysctl_set_perm_empty_ctl_header() does not access the
ctl_table member anymore.

This also makes the element of sysctl_mount_point unnecessary, so drop
it at the same time.

Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
---
 fs/proc/proc_sysctl.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index fde7a2f773f0..7c0e27dc3d9d 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -30,9 +30,7 @@ static const struct file_operations proc_sys_dir_file_operations;
 static const struct inode_operations proc_sys_dir_operations;

 /* Support for permanently empty directories */
-static struct ctl_table sysctl_mount_point[] = {
-	{ }
-};
+static struct ctl_table sysctl_mount_point[] = { };

 /**
  * register_sysctl_mount_point() - registers a sysctl mount point
@@ -232,8 +230,7 @@ static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header)
 		return -EROFS;

 	/* Am I creating a permanently empty directory? */
-	if (header->ctl_table_size > 0 &&
-	    sysctl_is_perm_empty_ctl_header(header)) {
+	if (sysctl_is_perm_empty_ctl_header(header)) {
 		if (!RB_EMPTY_ROOT(&dir->root))
 			return -EINVAL;
 		sysctl_set_perm_empty_ctl_header(dir_h);

-- 
2.44.0