afs: Fix missing XDR advance in xdr_decode_{AFS,YFS}FSFetchStatus()

commit c72057b56f7e24865840a6961d801a7f21d30a5f upstream.

If we receive a status record that has VNOVNODE set in the abort field,
xdr_decode_AFSFetchStatus() and xdr_decode_YFSFetchStatus() don't advance
the XDR pointer, thereby corrupting anything subsequent decodes from the
same block of data.

This has the potential to affect AFS.InlineBulkStatus and
YFS.InlineBulkStatus operation, but probably doesn't since the status
records are extracted as individual blocks of data and the buffer pointer
is reset between blocks.

It does affect YFS.RemoveFile2 operation, corrupting the volsync record -
though that is not currently used.

Other operations abort the entire operation rather than returning an error
inline, in which case there is no decoding to be done.

Fix this by unconditionally advancing the xdr pointer.

Fixes: 684b0f68cf1c ("afs: Fix AFSFetchStatus decoder to provide OpenAFS compatibility")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c
index 6f84231f11a5d7c8eadda8758ffae0c37e0d06fe..b096121fddc989b5d43d56b295486e02cbbdee3b 100644 (file)
--- a/fs/afs/fsclient.c
+++ b/fs/afs/fsclient.c
@@ -65,6 +65,7 @@ static int xdr_decode_AFSFetchStatus(const __be32 **_bp,
        bool inline_error = (call->operation_ID == afs_FS_InlineBulkStatus);
        u64 data_version, size;
        u32 type, abort_code;
+       int ret;
 
        abort_code = ntohl(xdr->abort_code);
 
@@ -78,7 +79,7 @@ static int xdr_decode_AFSFetchStatus(const __be32 **_bp,
                         */
                        status->abort_code = abort_code;
                        scb->have_error = true;
-                       return 0;
+                       goto good;
                }
 
                pr_warn("Unknown AFSFetchStatus version %u\n", ntohl(xdr->if_version));
@@ -87,7 +88,7 @@ static int xdr_decode_AFSFetchStatus(const __be32 **_bp,
 
        if (abort_code != 0 && inline_error) {
                status->abort_code = abort_code;
-               return 0;
+               goto good;
        }
 
        type = ntohl(xdr->type);
@@ -123,13 +124,16 @@ static int xdr_decode_AFSFetchStatus(const __be32 **_bp,
        data_version |= (u64)ntohl(xdr->data_version_hi) << 32;
        status->data_version = data_version;
        scb->have_status = true;
-
+good:
+       ret = 0;
+advance:
        *_bp = (const void *)*_bp + sizeof(*xdr);
-       return 0;
+       return ret;
 
 bad:
        xdr_dump_bad(*_bp);
-       return afs_protocol_error(call, -EBADMSG, afs_eproto_bad_status);
+       ret = afs_protocol_error(call, -EBADMSG, afs_eproto_bad_status);
+       goto advance;
 }
 
 static time64_t xdr_decode_expiry(struct afs_call *call, u32 expiry)

diff --git a/fs/afs/yfsclient.c b/fs/afs/yfsclient.c
index 3ee7abf4b2d02e73ecfc3225bcce9a30a374a855..323bec02cc9b39c7fd76dfd3275d30f344be8043 100644 (file)
--- a/fs/afs/yfsclient.c
+++ b/fs/afs/yfsclient.c
@@ -186,13 +186,14 @@ static int xdr_decode_YFSFetchStatus(const __be32 **_bp,
        const struct yfs_xdr_YFSFetchStatus *xdr = (const void *)*_bp;
        struct afs_file_status *status = &scb->status;
        u32 type;
+       int ret;
 
        status->abort_code = ntohl(xdr->abort_code);
        if (status->abort_code != 0) {
                if (status->abort_code == VNOVNODE)
                        status->nlink = 0;
                scb->have_error = true;
-               return 0;
+               goto good;
        }
 
        type = ntohl(xdr->type);
@@ -220,13 +221,16 @@ static int xdr_decode_YFSFetchStatus(const __be32 **_bp,
        status->size            = xdr_to_u64(xdr->size);
        status->data_version    = xdr_to_u64(xdr->data_version);
        scb->have_status        = true;
-
+good:
+       ret = 0;
+advance:
        *_bp += xdr_size(xdr);
-       return 0;
+       return ret;
 
 bad:
        xdr_dump_bad(*_bp);
-       return afs_protocol_error(call, -EBADMSG, afs_eproto_bad_status);
+       ret = afs_protocol_error(call, -EBADMSG, afs_eproto_bad_status);
+       goto advance;
 }
 
 /*