The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From f0d07a98a070bb5e443df19c3aa55693cbca9341 Mon Sep 17 00:00:00 2001
From: Eric Biggers ebiggers@google.com Date: Mon, 20 Jan 2020 14:31:59 -0800 Subject: [PATCH] ubifs: don't trigger assertion on invalid no-key filename
If userspace provides an invalid fscrypt no-key filename which encodes a hash value with any of the UBIFS node type bits set (i.e. the high 3 bits), gracefully report ENOENT rather than triggering ubifs_assert().
Test case with kvm-xfstests shell:
. fs/ubifs/config . ~/xfstests/common/encrypt dev=$(__blkdev_to_ubi_volume /dev/vdc) ubiupdatevol $dev -t mount $dev /mnt -t ubifs mkdir /mnt/edir xfs_io -c set_encpolicy /mnt/edir rm /mnt/edir/_,,,,,DAAAAAAAAAAAAAAAAAAAAAAAAAA
With the bug, the following assertion fails on the 'rm' command:
[ 19.066048] UBIFS error (ubi0:0 pid 379): ubifs_assert_failed: UBIFS assert failed: !(hash & ~UBIFS_S_KEY_HASH_MASK), in fs/ubifs/key.h:170
Fixes: f4f61d2cc6d8 ("ubifs: Implement encrypted filenames") Cc: stable@vger.kernel.org # v4.10+ Link: https://lore.kernel.org/r/20200120223201.241390-5-ebiggers@kernel.org Signed-off-by: Eric Biggers ebiggers@google.com
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 636c3222c230..5f937226976a 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -228,6 +228,8 @@ static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry, if (nm.hash) { ubifs_assert(c, fname_len(&nm) == 0); ubifs_assert(c, fname_name(&nm) == NULL); + if (nm.hash & ~UBIFS_S_KEY_HASH_MASK) + goto done; /* ENOENT */ dent_key_init_hash(c, &key, dir->i_ino, nm.hash); err = ubifs_tnc_lookup_dh(c, &key, dent, nm.minor_hash); } else {