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authorSteve French <smfrench@gmail.com>2014-08-15 23:49:01 -0500
committerSteve French <smfrench@gmail.com>2014-08-15 23:49:01 -0500
commit754789a1c046106cfdb067102642f73e0fd35fb3 (patch)
treee1c9ea733b2647a868f68eaaff987750adad83bb /fs
parent024408062b21af7316221c420ff16bdaac478fa8 (diff)
downloadlinux-stericsson-754789a1c046106cfdb067102642f73e0fd35fb3.tar.gz
[CIFS] Workaround MacOS server problem with SMB2.1 write
response Writes fail to Mac servers with SMB2.1 mounts (works with cifs though) due to them sending an incorrect RFC1001 length for the SMB2.1 Write response. Workaround this problem. MacOS server sends a write response with 3 bytes of pad beyond the end of the SMB itself. The RFC1001 length is 3 bytes more than the sum of the SMB2.1 header length + the write reponse. Incorporate feedback from Jeff and JRA to allow servers to send a tcp frame that is even more than three bytes too long (ie much longer than the SMB2/SMB3 request that it contains) but we do log it once now. In the earlier version of the patch I had limited how far off the length field could be before we fail the request. Signed-off-by: Steve French <smfrench@gmail.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/cifs/smb2misc.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index f2e6ac29a8d6..4aa7a0f07d6e 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -178,9 +178,24 @@ smb2_check_message(char *buf, unsigned int length)
/* Windows 7 server returns 24 bytes more */
if (clc_len + 20 == len && command == SMB2_OPLOCK_BREAK_HE)
return 0;
- /* server can return one byte more */
+ /* server can return one byte more due to implied bcc[0] */
if (clc_len == 4 + len + 1)
return 0;
+
+ /*
+ * MacOS server pads after SMB2.1 write response with 3 bytes
+ * of junk. Other servers match RFC1001 len to actual
+ * SMB2/SMB3 frame length (header + smb2 response specific data)
+ * Log the server error (once), but allow it and continue
+ * since the frame is parseable.
+ */
+ if (clc_len < 4 /* RFC1001 header size */ + len) {
+ printk_once(KERN_WARNING
+ "SMB2 server sent bad RFC1001 len %d not %d\n",
+ len, clc_len - 4);
+ return 0;
+ }
+
return 1;
}
return 0;