diff options
| author | Danilo Krummrich <[email protected]> | 2018-04-10 16:31:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2018-04-11 10:28:33 -0700 |
| commit | a0b0d1c345d0317efe594df268feb5ccc99f651e (patch) | |
| tree | eb319255e1da3162d3e1cbd694618f9f46bb6496 | |
| parent | 21dae0ad07e6c4d3fa1bd9a91a8b51be316a5111 (diff) | |
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/[email protected]
Fixes: 0e47c99d7fe25 ("sysctl: Replace root_list with links between sysctl_table_sets")
Signed-off-by: Danilo Krummrich <[email protected]>
Acked-by: Kees Cook <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: "Luis R . Rodriguez" <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
| -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 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 */ |