4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
[ Upstream commit bcd89270d93b7edebb5de5e5e7dca1a77a33496e ]
Servers may send a callback array that is the same size as
the FID array, or an empty array. If the callback count is
0, the code would attempt to read (fid_count * 12) bytes of
data, which would fail and result in an unmarshalling error.
This would lead to stale data for remotely modified files
or directories.
Store the callback array size in the internal afs_call
structure and use that to determine the amount of data to
read.
Signed-off-by: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/afs/cmservice.c | 11 +++++------
fs/afs/internal.h | 5 ++++-
2 files changed, 9 insertions(+), 7 deletions(-)
--- a/fs/afs/cmservice.c
+++ b/fs/afs/cmservice.c
@@ -168,7 +168,6 @@ static int afs_deliver_cb_callback(struc
struct afs_callback *cb;
struct afs_server *server;
__be32 *bp;
- u32 tmp;
int ret, loop;
_enter("{%u}", call->unmarshall);
@@ -230,9 +229,9 @@ static int afs_deliver_cb_callback(struc
if (ret < 0)
return ret;
- tmp = ntohl(call->tmp);
- _debug("CB count: %u", tmp);
- if (tmp != call->count && tmp != 0)
+ call->count2 = ntohl(call->tmp);
+ _debug("CB count: %u", call->count2);
+ if (call->count2 != call->count && call->count2 != 0)
return -EBADMSG;
call->offset = 0;
call->unmarshall++;
@@ -240,14 +239,14 @@ static int afs_deliver_cb_callback(struc
case 4:
_debug("extract CB array");
ret = afs_extract_data(call, call->buffer,
- call->count * 3 * 4, false);
+ call->count2 * 3 * 4, false);
if (ret < 0)
return ret;
_debug("unmarshall CB array");
cb = call->request;
bp = call->buffer;
- for (loop = call->count; loop > 0; loop--, cb++) {
+ for (loop = call->count2; loop > 0; loop--, cb++) {
cb->version = ntohl(*bp++);
cb->expiry = ntohl(*bp++);
cb->type = ntohl(*bp++);
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -105,7 +105,10 @@ struct afs_call {
unsigned request_size; /* size of request data */
unsigned reply_max; /* maximum size of reply */
unsigned first_offset; /* offset into mapping[first] */
- unsigned last_to; /* amount of mapping[last] */
+ union {
+ unsigned last_to; /* amount of mapping[last] */
+ unsigned count2; /* count used in unmarshalling */
+ };
unsigned char unmarshall; /* unmarshalling phase */
bool incoming; /* T if incoming call */
bool send_pages; /* T if data from mapping should be sent */