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ip_frag: check fragment length of incoming packet

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Under some conditions ill-formed fragments might cause
reassembly code to corrupt mbufs and/or crash.
Let say the following fragments sequence:
<ofs=0,len=100, flags=MF>
<ofs=96,len=100, flags=MF>
<ofs=200,len=0,flags=MF>
<ofs=200,len=100,flags=0>
can trigger the problem.
To overcome such situation, added check that fragment length
of incoming value is greater than zero.

Fixes: 601e279df074 ("ip_frag: move fragmentation/reassembly headers into a library")
Fixes: 4f1a8f633862 ("ip_frag: add IPv6 reassembly")
Cc: stable@dpdk.org

Reported-by: Ryan E Hall <ryan.e.hall@intel.com>
Reported-by: Alexander V Gutkin <alexander.v.gutkin@intel.com>
Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
This commit is contained in:
Konstantin Ananyev 2018-11-05 12:18:57 +00:00 committed by Thomas Monjalon
parent 7b178300ac
commit 7f0983ee33
2 changed files with 35 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
lib/librte_ip_frag/rte_ipv4_reassembly.c
View File

@ -36,8 +36,11 @@ ipv4_frag_reassemble(struct ip_frag_pkt *fp)
/* previous fragment found. */
if(fp->frags[i].ofs + fp->frags[i].len == ofs) {
RTE_ASSERT(curr_idx != i);
/* adjust start of the last fragment data. */
rte_pktmbuf_adj(m, (uint16_t)(m->l2_len + m->l3_len));
rte_pktmbuf_adj(m,
(uint16_t)(m->l2_len + m->l3_len));
rte_pktmbuf_chain(fp->frags[i].mb, m);
/* this mbuf should not be accessed directly */
@ -96,14 +99,14 @@ ipv4_frag_reassemble(struct ip_frag_pkt *fp)
*/
struct rte_mbuf *
rte_ipv4_frag_reassemble_packet(struct rte_ip_frag_tbl *tbl,
struct rte_ip_frag_death_row *dr, struct rte_mbuf *mb, uint64_t tms,
struct ipv4_hdr *ip_hdr)
struct rte_ip_frag_death_row *dr, struct rte_mbuf *mb, uint64_t tms,
struct ipv4_hdr *ip_hdr)
{
struct ip_frag_pkt *fp;
struct ip_frag_key key;
const unaligned_uint64_t *psd;
uint16_t ip_len;
uint16_t flag_offset, ip_ofs, ip_flag;
int32_t ip_len;
flag_offset = rte_be_to_cpu_16(ip_hdr->fragment_offset);
ip_ofs = (uint16_t)(flag_offset & IPV4_HDR_OFFSET_MASK);
@ -116,12 +119,11 @@ rte_ipv4_frag_reassemble_packet(struct rte_ip_frag_tbl *tbl,
key.key_len = IPV4_KEYLEN;
ip_ofs *= IPV4_HDR_OFFSET_UNITS;
ip_len = (uint16_t)(rte_be_to_cpu_16(ip_hdr->total_length) -
mb->l3_len);
ip_len = rte_be_to_cpu_16(ip_hdr->total_length) - mb->l3_len;
IP_FRAG_LOG(DEBUG, "%s:%d:\n"
"mbuf: %p, tms: %" PRIu64
", key: <%" PRIx64 ", %#x>, ofs: %u, len: %u, flags: %#x\n"
", key: <%" PRIx64 ", %#x>, ofs: %u, len: %d, flags: %#x\n"
"tbl: %p, max_cycles: %" PRIu64 ", entry_mask: %#x, "
"max_entries: %u, use_entries: %u\n\n",
__func__, __LINE__,
@ -129,6 +131,12 @@ rte_ipv4_frag_reassemble_packet(struct rte_ip_frag_tbl *tbl,
tbl, tbl->max_cycles, tbl->entry_mask, tbl->max_entries,
tbl->use_entries);
/* check that fragment length is greater then zero. */
if (ip_len <= 0) {
IP_FRAG_MBUF2DR(dr, mb);
return NULL;
}
/* try to find/add entry into the fragment's table. */
if ((fp = ip_frag_find(tbl, dr, &key, tms)) == NULL) {
IP_FRAG_MBUF2DR(dr, mb);

28
lib/librte_ip_frag/rte_ipv6_reassembly.c
View File

@ -59,8 +59,11 @@ ipv6_frag_reassemble(struct ip_frag_pkt *fp)
/* previous fragment found. */
if (fp->frags[i].ofs + fp->frags[i].len == ofs) {
RTE_ASSERT(curr_idx != i);
/* adjust start of the last fragment data. */
rte_pktmbuf_adj(m, (uint16_t)(m->l2_len + m->l3_len));
rte_pktmbuf_adj(m,
(uint16_t)(m->l2_len + m->l3_len));
rte_pktmbuf_chain(fp->frags[i].mb, m);
/* this mbuf should not be accessed directly */
@ -135,12 +138,13 @@ ipv6_frag_reassemble(struct ip_frag_pkt *fp)
#define FRAG_OFFSET(x) (rte_cpu_to_be_16(x) >> 3)
struct rte_mbuf *
rte_ipv6_frag_reassemble_packet(struct rte_ip_frag_tbl *tbl,
struct rte_ip_frag_death_row *dr, struct rte_mbuf *mb, uint64_t tms,
struct ipv6_hdr *ip_hdr, struct ipv6_extension_fragment *frag_hdr)
struct rte_ip_frag_death_row *dr, struct rte_mbuf *mb, uint64_t tms,
struct ipv6_hdr *ip_hdr, struct ipv6_extension_fragment *frag_hdr)
{
struct ip_frag_pkt *fp;
struct ip_frag_key key;
uint16_t ip_len, ip_ofs;
uint16_t ip_ofs;
int32_t ip_len;
rte_memcpy(&key.src_dst[0], ip_hdr->src_addr, 16);
rte_memcpy(&key.src_dst[2], ip_hdr->dst_addr, 16);
@ -151,15 +155,17 @@ rte_ipv6_frag_reassemble_packet(struct rte_ip_frag_tbl *tbl,
ip_ofs = FRAG_OFFSET(frag_hdr->frag_data) * 8;
/*
* as per RFC2460, payload length contains all extension headers as well.
* since we don't support anything but frag headers, this is what we remove
* from the payload len.
* as per RFC2460, payload length contains all extension headers
* as well.
* since we don't support anything but frag headers,
* this is what we remove from the payload len.
*/
ip_len = rte_be_to_cpu_16(ip_hdr->payload_len) - sizeof(*frag_hdr);
IP_FRAG_LOG(DEBUG, "%s:%d:\n"
"mbuf: %p, tms: %" PRIu64
", key: <" IPv6_KEY_BYTES_FMT ", %#x>, ofs: %u, len: %u, flags: %#x\n"
", key: <" IPv6_KEY_BYTES_FMT ", %#x>, "
"ofs: %u, len: %d, flags: %#x\n"
"tbl: %p, max_cycles: %" PRIu64 ", entry_mask: %#x, "
"max_entries: %u, use_entries: %u\n\n",
__func__, __LINE__,
@ -168,6 +174,12 @@ rte_ipv6_frag_reassemble_packet(struct rte_ip_frag_tbl *tbl,
tbl, tbl->max_cycles, tbl->entry_mask, tbl->max_entries,
tbl->use_entries);
/* check that fragment length is greater then zero. */
if (ip_len <= 0) {
IP_FRAG_MBUF2DR(dr, mb);
return NULL;
}
/* try to find/add entry into the fragment's table. */
fp = ip_frag_find(tbl, dr, &key, tms);
if (fp == NULL) {