The second call to ofpbuf_put_zeros() could cause the 'eth' pointer to
be invalidated.
It appears that this does not fix a real bug because the existing callers
all preallocate 128 bytes of tailroom, but the interface doesn't document
that requirement.
---
lib/packets.c | 29 +++++++----------------------
1 files changed, 7 insertions(+), 22 deletions(-)
diff --git a/lib/packets.c b/lib/packets.c
index 8cb1b6d..f16e749 100644
--- a/lib/packets.c
+++ b/lib/packets.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2009, 2010 Nicira Networks.
+ * Copyright (c) 2009, 2010, 2011 Nicira Networks.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -66,28 +66,13 @@ void
compose_benign_packet(struct ofpbuf *b, const char *tag, uint16_t snap_type,
const uint8_t eth_src[ETH_ADDR_LEN])
{
- struct eth_header *eth;
- struct llc_snap_header *llc_snap;
+ size_t tag_size = strlen(tag) + 1;
+ char *payload;
- /* Compose basic packet structure. (We need the payload size to stick into
- * the 802.2 header.) */
- ofpbuf_clear(b);
- eth = ofpbuf_put_zeros(b, ETH_HEADER_LEN);
- llc_snap = ofpbuf_put_zeros(b, LLC_SNAP_HEADER_LEN);
- ofpbuf_put(b, tag, strlen(tag) + 1); /* Includes null byte. */
- ofpbuf_put(b, eth_src, ETH_ADDR_LEN);
-
- /* Compose 802.2 header. */
- memcpy(eth->eth_dst, eth_addr_broadcast, ETH_ADDR_LEN);
- memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
- eth->eth_type = htons(b->size - ETH_HEADER_LEN);
-
- /* Compose LLC, SNAP headers. */
- llc_snap->llc.llc_dsap = LLC_DSAP_SNAP;
- llc_snap->llc.llc_ssap = LLC_SSAP_SNAP;
- llc_snap->llc.llc_cntl = LLC_CNTL_SNAP;
- memcpy(llc_snap->snap.snap_org, "\x00\x23\x20", 3);
- llc_snap->snap.snap_type = htons(snap_type);
+ payload = snap_compose(b, eth_addr_broadcast, eth_src, 0x002320, snap_type,
+ tag_size + ETH_ADDR_LEN);
+ memcpy(payload, tag, tag_size);
+ memcpy(payload + tag_size, eth_src, ETH_ADDR_LEN);
}
/* Stores the string representation of the IPv6 address 'addr' into the
--
1.7.1
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