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authorDanilo Krummrich <danilokrummrich@dk-develop.de>2018-04-10 16:31:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-11 10:28:33 -0700
commita0b0d1c345d0317efe594df268feb5ccc99f651e (patch)
treeeb319255e1da3162d3e1cbd694618f9f46bb6496
parentproc: use set_puts() at /proc/*/wchan (diff)
downloadwireguard-linux-a0b0d1c345d0317efe594df268feb5ccc99f651e.tar.xz
wireguard-linux-a0b0d1c345d0317efe594df268feb5ccc99f651e.zip
fs/proc/proc_sysctl.c: fix potential page fault while unregistering sysctl table
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>
-rw-r--r--fs/proc/proc_sysctl.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index c41ab261397d..7da10e595297 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -707,7 +707,10 @@ 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 */