[Cluster-devel] [RFC PATCH dlm/next 03/16] fs: dlm: add check for minimum allocation length

[Alexander Aring <aahringo@redhat.com>]

While running tcpkill I experienced invalid header length values while
receiving to check that a node doesn't try to send a invalid dlm message
we also check on applications minimum allocation limit.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 fs/dlm/lowcomms.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index ffea14c50d46..3ab56272ee2d 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -1355,7 +1355,8 @@ void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
 	struct writequeue_entry *e;
 	int offset = 0;
 
-	if (len > LOWCOMMS_MAX_TX_BUFFER_LEN) {
+	if (len > LOWCOMMS_MAX_TX_BUFFER_LEN ||
+	    len < sizeof(struct dlm_header)) {
 		BUILD_BUG_ON(PAGE_SIZE < LOWCOMMS_MAX_TX_BUFFER_LEN);
 		log_print("failed to allocate a buffer of size %d", len);
 		return NULL;
-- 
2.26.2