diff options
| author |   Dave Barach <dave@barachs.net> | 2019-09-04 12:09:32 -0400 |
|---|---|---|
| committer |   Dave Barach <openvpp@barachs.net> | 2019-09-07 01:26:58 +0000 |
| commit | c4abafd83df38051765352785b146277734701f4 (patch) | |
| tree | 12633dc1337661d1c4d408df2d1bca67e1d940bc /src/vnet/ip/ip6_forward.c | |
| parent | b736e75d5bb2d132fb00c35b6aabaa52e5f624ad (diff) | |
ip: fix udp/tcp checksum corner cases
When checksumming chained buffers with odd lengths: insert a
NULL byte, or the calculation fails.
Type: fix
Signed-off-by: Dave Barach <dave@barachs.net>
Signed-off-by: John Lo <loj@cisco.com>
Change-Id: I380f7c42897bdb28c8c29aa1c4cdaaa849cc9ecc
Diffstat (limited to 'src/vnet/ip/ip6_forward.c')
| -rw-r--r-- | src/vnet/ip/ip6_forward.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/src/vnet/ip/ip6_forward.c b/src/vnet/ip/ip6_forward.c index 252bdf975be..067db77c412 100644 --- a/src/vnet/ip/ip6_forward.c +++ b/src/vnet/ip/ip6_forward.c @@ -1017,7 +1017,8 @@ ip6_tcp_udp_icmp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0, u16 sum16, payload_length_host_byte_order; u32 i, n_this_buffer, n_bytes_left; u32 headers_size = sizeof (ip0[0]); - void *data_this_buffer; + u8 *data_this_buffer; + u8 length_odd; ASSERT (bogus_lengthp); *bogus_lengthp = 0; @@ -1025,7 +1026,7 @@ ip6_tcp_udp_icmp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0, /* Initialize checksum with ip header. */ sum0 = ip0->payload_length + clib_host_to_net_u16 (ip0->protocol); payload_length_host_byte_order = clib_net_to_host_u16 (ip0->payload_length); - data_this_buffer = (void *) (ip0 + 1); + data_this_buffer = (u8 *) (ip0 + 1); for (i = 0; i < ARRAY_LEN (ip0->src_address.as_uword); i++) { @@ -1078,14 +1079,27 @@ ip6_tcp_udp_icmp_compute_checksum (vlib_main_t * vm, vlib_buffer_t * p0, if (n_bytes_left == 0) break; + ASSERT (p0->flags & VLIB_BUFFER_NEXT_PRESENT); if (!(p0->flags & VLIB_BUFFER_NEXT_PRESENT)) { *bogus_lengthp = 1; return 0xfefe; } + + length_odd = (n_this_buffer & 1); + p0 = vlib_get_buffer (vm, p0->next_buffer); data_this_buffer = vlib_buffer_get_current (p0); n_this_buffer = clib_min (p0->current_length, n_bytes_left); + + if (PREDICT_FALSE (length_odd)) + { + /* Prepend a 0 or the resulting checksum will be incorrect. */ + data_this_buffer--; + n_this_buffer++; + n_bytes_left++; + data_this_buffer[0] = 0; + } } sum16 = ~ip_csum_fold (sum0); |