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authorAndy Lutomirski <luto@amacapital.net>2014-10-08 12:32:47 -0700
committerAndy Lutomirski <luto@amacapital.net>2014-10-08 12:32:47 -0700
commita1480dcc3c706e309a88884723446f2e84fedd5b (patch)
treefa2a425b8607586c11127ea35344d893e6a4a4f0 /fs
parentbfe01a5ba2490f299e1d2d5508cbbbadd897bbe9 (diff)
fs: Add a missing permission check to do_umount
Accessing do_remount_sb should require global CAP_SYS_ADMIN, but only one of the two call sites was appropriately protected. Fixes CVE-2014-7975. Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Diffstat (limited to 'fs')
-rw-r--r--fs/namespace.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index ef42d9bee212..7f67b463a5b4 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1356,6 +1356,8 @@ static int do_umount(struct mount *mnt, int flags)
* Special case for "unmounting" root ...
* we just try to remount it readonly.
*/
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
down_write(&sb->s_umount);
if (!(sb->s_flags & MS_RDONLY))
retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);

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