4.18-stable review patch. If anyone has any objections, please let me know.
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From: Amir Goldstein amir73il@gmail.com
commit 601350ff58d5415a001769532f6b8333820e5786 upstream.
KASAN detected slab-out-of-bounds access in printk from overlayfs, because string format used %*s instead of %.*s.
BUG: KASAN: slab-out-of-bounds in string+0x298/0x2d0 lib/vsprintf.c:604 Read of size 1 at addr ffff8801c36c66ba by task syz-executor2/27811
CPU: 0 PID: 27811 Comm: syz-executor2 Not tainted 4.19.0-rc5+ #36
...
printk+0xa7/0xcf kernel/printk/printk.c:1996 ovl_lookup_index.cold.15+0xe8/0x1f8 fs/overlayfs/namei.c:689
Reported-by: syzbot+376cea2b0ef340db3dd4@syzkaller.appspotmail.com Signed-off-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Miklos Szeredi mszeredi@redhat.com Fixes: 359f392ca53e ("ovl: lookup index entry for copy up origin") Cc: stable@vger.kernel.org # v4.13 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/overlayfs/namei.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -705,7 +705,7 @@ struct dentry *ovl_lookup_index(struct o index = NULL; goto out; } - pr_warn_ratelimited("overlayfs: failed inode index lookup (ino=%lu, key=%*s, err=%i);\n" + pr_warn_ratelimited("overlayfs: failed inode index lookup (ino=%lu, key=%.*s, err=%i);\n" "overlayfs: mount with '-o index=off' to disable inodes index.\n", d_inode(origin)->i_ino, name.len, name.name, err);