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authorMarc Dionne <marc.dionne@auristor.com>2017-03-16 16:27:44 +0000
committerDavid Howells <dhowells@redhat.com>2017-03-16 16:27:44 +0000
commitbcd89270d93b7edebb5de5e5e7dca1a77a33496e (patch)
tree3e196dac7eed6313b0cd3111002434efc8ed0bb8
parent627f46943ff90bcc32ddeb675d881c043c6fa2ae (diff)
downloadlinux-bcd89270d93b7edebb5de5e5e7dca1a77a33496e.tar.bz2
afs: Deal with an empty callback array
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@auristor.com>
-rw-r--r--fs/afs/cmservice.c11
-rw-r--r--fs/afs/internal.h5
2 files changed, 9 insertions, 7 deletions
diff --git a/fs/afs/cmservice.c b/fs/afs/cmservice.c
index 2edbdcbf6432..3062cceb5c2a 100644
--- a/fs/afs/cmservice.c
+++ b/fs/afs/cmservice.c
@@ -187,7 +187,6 @@ static int afs_deliver_cb_callback(struct afs_call *call)
struct afs_callback *cb;
struct afs_server *server;
__be32 *bp;
- u32 tmp;
int ret, loop;
_enter("{%u}", call->unmarshall);
@@ -249,9 +248,9 @@ static int afs_deliver_cb_callback(struct afs_call *call)
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++;
@@ -259,14 +258,14 @@ static int afs_deliver_cb_callback(struct afs_call *call)
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++);
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 5dfa56903a2d..8499870147ef 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -90,7 +90,10 @@ 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 */