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Apply patch from Simon to fix buffer overflow handling tcp_in.c which was discovered by Coverity

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This commit is contained in:
Dirk Ziegelmeier 2016-02-29 23:34:52 +01:00
parent 8e5663a32f
commit 9885d5d9f5
1 changed files with 13 additions and 7 deletions
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20
src/core/tcp_in.c
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@ -70,6 +70,7 @@
function. */
static struct tcp_seg inseg;
static struct tcp_hdr *tcphdr;
static u16_t tcphdr_optlen;
static u16_t tcphdr_opt1len;
static u8_t* tcphdr_opt2;
static u16_t tcp_optidx;
@ -157,7 +158,7 @@ tcp_input(struct pbuf *p, struct netif *inp)
/* Move the payload pointer in the pbuf so that it points to the
TCP data instead of the TCP header. */
hdrlen = TCPH_HDRLEN(tcphdr);
tcphdr_opt1len = (hdrlen * 4) - TCP_HLEN;
tcphdr_optlen = tcphdr_opt1len = (hdrlen * 4) - TCP_HLEN;
tcphdr_opt2 = NULL;
if (p->len < hdrlen * 4) {
if (p->len >= TCP_HLEN) {
@ -173,6 +174,12 @@ tcp_input(struct pbuf *p, struct netif *inp)
options in the next pbuf (adjusting p->tot_len) */
u8_t phret = pbuf_header(p, -(s16_t)tcphdr_opt1len);
LWIP_ASSERT("phret == 0", phret == 0);
if(tcphdr_optlen - tcphdr_opt1len > p->tot_len) {
/* drop short packets */
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
TCP_STATS_INC(tcp.lenerr);
goto dropped;
}
tcphdr_opt2 = (u8_t*)p->next->payload;
opt2len = optlen - tcphdr_opt1len;
phret = pbuf_header(p->next, -opt2len);
@ -1677,9 +1684,8 @@ tcp_parseopt(struct tcp_pcb *pcb)
#endif
/* Parse the TCP MSS option, if present. */
if (TCPH_HDRLEN(tcphdr) > 0x5) {
u16_t max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2;
for (tcp_optidx = 0; tcp_optidx < max_c; ) {
if (tcphdr_optlen != 0) {
for (tcp_optidx = 0; tcp_optidx < tcphdr_optlen; ) {
u8_t opt = tcp_getoptbyte();
switch (opt) {
case LWIP_TCP_OPT_EOL:
@ -1692,7 +1698,7 @@ tcp_parseopt(struct tcp_pcb *pcb)
break;
case LWIP_TCP_OPT_MSS:
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n"));
if (tcp_getoptbyte() != LWIP_TCP_OPT_LEN_MSS || (tcp_optidx - 2 + LWIP_TCP_OPT_LEN_MSS) > max_c) {
if (tcp_getoptbyte() != LWIP_TCP_OPT_LEN_MSS || (tcp_optidx - 2 + LWIP_TCP_OPT_LEN_MSS) > tcphdr_optlen) {
/* Bad length */
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
return;
@ -1706,7 +1712,7 @@ tcp_parseopt(struct tcp_pcb *pcb)
#if LWIP_WND_SCALE
case LWIP_TCP_OPT_WS:
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: WND_SCALE\n"));
if (tcp_getoptbyte() != LWIP_TCP_OPT_LEN_WS || (tcp_optidx - 2 + LWIP_TCP_OPT_LEN_WS) > max_c) {
if (tcp_getoptbyte() != LWIP_TCP_OPT_LEN_WS || (tcp_optidx - 2 + LWIP_TCP_OPT_LEN_WS) > tcphdr_optlen) {
/* Bad length */
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
return;
@ -1732,7 +1738,7 @@ tcp_parseopt(struct tcp_pcb *pcb)
#if LWIP_TCP_TIMESTAMPS
case LWIP_TCP_OPT_TS:
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n"));
if (tcp_getoptbyte() != LWIP_TCP_OPT_LEN_TS || (tcp_optidx - 2 + LWIP_TCP_OPT_LEN_TS) > max_c) {
if (tcp_getoptbyte() != LWIP_TCP_OPT_LEN_TS || (tcp_optidx - 2 + LWIP_TCP_OPT_LEN_TS) > tcphdr_optlen) {
/* Bad length */
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
return;