From 97c1df3e54e811aed484a036a798b4b25d002ecf Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 6 Jun 2016 15:36:07 -0500 Subject: [PATCH 1/2] mnt: If fs_fully_visible fails call put_filesystem. Add this trivial missing error handling. Cc: stable@vger.kernel.org Fixes: 1b852bceb0d1 ("mnt: Refactor the logic for mounting sysfs and proc in a user namespace") Signed-off-by: "Eric W. Biederman" --- fs/namespace.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/namespace.c b/fs/namespace.c index 4fb1691b4355..9d45c8a3414f 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2409,8 +2409,10 @@ static int do_new_mount(struct path *path, const char *fstype, int flags, mnt_flags |= MNT_NODEV | MNT_LOCK_NODEV; } if (type->fs_flags & FS_USERNS_VISIBLE) { - if (!fs_fully_visible(type, &mnt_flags)) + if (!fs_fully_visible(type, &mnt_flags)) { + put_filesystem(type); return -EPERM; + } } } From d71ed6c930ac7d8f88f3cef6624a7e826392d61f Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Fri, 27 May 2016 14:50:05 -0500 Subject: [PATCH 2/2] mnt: fs_fully_visible test the proper mount for MNT_LOCKED MNT_LOCKED implies on a child mount implies the child is locked to the parent. So while looping through the children the children should be tested (not their parent). Typically an unshare of a mount namespace locks all mounts together making both the parent and the slave as locked but there are a few corner cases where other things work. Cc: stable@vger.kernel.org Fixes: ceeb0e5d39fc ("vfs: Ignore unlocked mounts in fs_fully_visible") Reported-by: Seth Forshee Signed-off-by: "Eric W. Biederman" --- fs/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/namespace.c b/fs/namespace.c index 9d45c8a3414f..a7ec92c051f5 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3273,7 +3273,7 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags) list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) { struct inode *inode = child->mnt_mountpoint->d_inode; /* Only worry about locked mounts */ - if (!(mnt_flags & MNT_LOCKED)) + if (!(child->mnt.mnt_flags & MNT_LOCKED)) continue; /* Is the directory permanetly empty? */ if (!is_empty_dir_inode(inode))