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Diffstat (limited to 'net/9p/client.c')
-rw-r--r--net/9p/client.c25
1 files changed, 16 insertions, 9 deletions
diff --git a/net/9p/client.c b/net/9p/client.c
index 33717b1b84d8..20088aa06343 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -469,20 +469,11 @@ p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
 	int err;
 
 	pdu->offset = 0;
-	if (pdu->size == 0)
-		pdu->size = 7;
 
 	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
 	if (err)
 		goto rewind_and_exit;
 
-	pdu->size = r_size;
-	pdu->id = r_type;
-	pdu->tag = r_tag;
-
-	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
-		 pdu->size, pdu->id, pdu->tag);
-
 	if (type)
 		*type = r_type;
 	if (tag)
@@ -490,6 +481,16 @@ p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
 	if (size)
 		*size = r_size;
 
+	if (pdu->size != r_size || r_size < 7) {
+		err = -EINVAL;
+		goto rewind_and_exit;
+	}
+
+	pdu->id = r_type;
+	pdu->tag = r_tag;
+
+	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
+		 pdu->size, pdu->id, pdu->tag);
 
 rewind_and_exit:
 	if (rewind)
@@ -516,6 +517,12 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
 	int ecode;
 
 	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
+	if (req->rc->size >= c->msize) {
+		p9_debug(P9_DEBUG_ERROR,
+			 "requested packet size too big: %d\n",
+			 req->rc->size);
+		return -EIO;
+	}
 	/*
 	 * dump the response from server
 	 * This should be after check errors which poplulate pdu_fcall.