diff options
author | Danilo Krummrich <danilokrummrich@dk-develop.de> | 2018-04-11 02:31:38 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-30 08:47:38 +0300 |
commit | b4b8334a00f4a7d61e9baad2d456703da3c5252f (patch) | |
tree | d735e3dd979aac8950ce01f07991d24fd32ea7e7 /fs | |
parent | af794b799a80cb855e251de3748a25f3700f0587 (diff) | |
download | linux-b4b8334a00f4a7d61e9baad2d456703da3c5252f.tar.xz |
fs/proc/proc_sysctl.c: fix potential page fault while unregistering sysctl table
[ Upstream commit a0b0d1c345d0317efe594df268feb5ccc99f651e ]
proc_sys_link_fill_cache() does not take currently unregistering sysctl
tables into account, which might result into a page fault in
sysctl_follow_link() - add a check to fix it.
This bug has been present since v3.4.
Link: http://lkml.kernel.org/r/20180228013506.4915-1-danilokrummrich@dk-develop.de
Fixes: 0e47c99d7fe25 ("sysctl: Replace root_list with links between sysctl_table_sets")
Signed-off-by: Danilo Krummrich <danilokrummrich@dk-develop.de>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/proc/proc_sysctl.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index f92d5dd578a4..b9226c7e0a88 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -617,7 +617,10 @@ static bool proc_sys_link_fill_cache(struct file *file, struct ctl_table *table) { bool ret = true; + head = sysctl_head_grab(head); + if (IS_ERR(head)) + return false; if (S_ISLNK(table->mode)) { /* It is not an error if we can not follow the link ignore it */ |