From: Jeff Layton <jlayton@kernel.org>
Date: Thu, 26 Sep 2019 16:05:11 -0400
Subject: ceph: just skip unrecognized info in ceph_reply_info_extra
Git-commit: 1d3f87233e26362fc3d4e59f0f31a71b570f90b9
Patch-mainline: v5.4-rc4
References: bsc#1157182

In the future, we're going to want to extend the ceph_reply_info_extra
for create replies. Currently though, the kernel code doesn't accept an
extra blob that is larger than the expected data.

Change the code to skip over any unrecognized fields at the end of the
extra blob, rather than returning -EIO.

Cc: stable@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>
---
 fs/ceph/mds_client.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index a8a8f84f3bbf..a5163296d9d9 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -384,8 +384,8 @@ static int parse_reply_info_readdir(void **p, void *end,
 	}
 
 done:
-	if (*p != end)
-		goto bad;
+	/* Skip over any unrecognized fields */
+	*p = end;
 	return 0;
 
 bad:
@@ -406,12 +406,10 @@ static int parse_reply_info_filelock(void **p, void *end,
 		goto bad;
 
 	info->filelock_reply = *p;
-	*p += sizeof(*info->filelock_reply);
 
-	if (unlikely(*p != end))
-		goto bad;
+	/* Skip over any unrecognized fields */
+	*p = end;
 	return 0;
-
 bad:
 	return -EIO;
 }
@@ -425,18 +423,21 @@ static int parse_reply_info_create(void **p, void *end,
 {
 	if (features == (u64)-1 ||
 	    (features & CEPH_FEATURE_REPLY_CREATE_INODE)) {
+		/* Malformed reply? */
 		if (*p == end) {
 			info->has_create_ino = false;
 		} else {
 			info->has_create_ino = true;
-			info->ino = ceph_decode_64(p);
+			ceph_decode_64_safe(p, end, info->ino, bad);
 		}
+	} else {
+		if (*p != end)
+			goto bad;
 	}
 
-	if (unlikely(*p != end))
-		goto bad;
+	/* Skip over any unrecognized fields */
+	*p = end;
 	return 0;
-
 bad:
 	return -EIO;
 }