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authorLinus Torvalds <torvalds@linux-foundation.org>2016-06-22 14:11:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-06-22 14:11:24 -0700
commitf9020d17416ae62f1b1c6459d61e65abb4af79b5 (patch)
tree1b55506a178ffc54be3f86dcafd6f5544dd77c39 /fs
parent144b5ae3e343f193a6a7edef8f30aab4fad2d12b (diff)
parent695e9df010e40f407f4830dc11d53dce957710ba (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull userns fix from Eric Biederman: "This contains just a single small patch that fixes a tiny hole in the logic of allowing unprivileged mounting of proc and sysfs. In practice I don't think anyone is affected because having MNT_RDONLY clear in mnt->mnt_flags but MS_RDONLY set in sb->s_flags is very weird for a filesystem, and weirder for proc and sysfs. However if it happens let's handle it correctly and then no one has to to worry about this crazy case" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: mnt: Account for MS_RDONLY in fs_fully_visible
Diffstat (limited to 'fs')
-rw-r--r--fs/namespace.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index a7ec92c051f5..783004af5707 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3247,6 +3247,10 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags)
if (mnt->mnt.mnt_sb->s_iflags & SB_I_NOEXEC)
mnt_flags &= ~(MNT_LOCK_NOSUID | MNT_LOCK_NOEXEC);
+ /* Don't miss readonly hidden in the superblock flags */
+ if (mnt->mnt.mnt_sb->s_flags & MS_RDONLY)
+ mnt_flags |= MNT_LOCK_READONLY;
+
/* Verify the mount flags are equal to or more permissive
* than the proposed new mount.
*/