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Do more bounds checking and length checking.

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Don't run past the end of the captured data, and don't run past the end
of the packet (i.e., don't make the length variable go negative).

Also, stop dissecting if the message length isn't valid.
This commit is contained in:
Guy Harris 2014-11-11 16:49:39 -08:00
parent 9255c9b05b
commit 4038f83ebf
1 changed files with 43 additions and 13 deletions
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56
print-olsr.c
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@ -178,7 +178,7 @@ struct olsr_lq_neighbor6 {
/*
* print a neighbor list with LQ extensions.
*/
static void
static int
olsr_print_lq_neighbor4(netdissect_options *ndo,
const u_char *msg_data, u_int hello_len)
{
@ -187,6 +187,8 @@ olsr_print_lq_neighbor4(netdissect_options *ndo,
while (hello_len >= sizeof(struct olsr_lq_neighbor4)) {
lq_neighbor = (struct olsr_lq_neighbor4 *)msg_data;
if (!ND_TTEST(*lq_neighbor))
return (-1);
ND_PRINT((ndo, "\n\t neighbor %s, link-quality %.2lf%%"
", neighbor-link-quality %.2lf%%",
@ -197,10 +199,11 @@ olsr_print_lq_neighbor4(netdissect_options *ndo,
msg_data += sizeof(struct olsr_lq_neighbor4);
hello_len -= sizeof(struct olsr_lq_neighbor4);
}
return (0);
}
#if INET6
static void
static int
olsr_print_lq_neighbor6(netdissect_options *ndo,
const u_char *msg_data, u_int hello_len)
{
@ -209,6 +212,8 @@ olsr_print_lq_neighbor6(netdissect_options *ndo,
while (hello_len >= sizeof(struct olsr_lq_neighbor6)) {
lq_neighbor = (struct olsr_lq_neighbor6 *)msg_data;
if (!ND_TTEST(*lq_neighbor))
return (-1);
ND_PRINT((ndo, "\n\t neighbor %s, link-quality %.2lf%%"
", neighbor-link-quality %.2lf%%",
@ -219,13 +224,14 @@ olsr_print_lq_neighbor6(netdissect_options *ndo,
msg_data += sizeof(struct olsr_lq_neighbor6);
hello_len -= sizeof(struct olsr_lq_neighbor6);
}
return (0);
}
#endif /* INET6 */
/*
* print a neighbor list.
*/
static void
static int
olsr_print_neighbor(netdissect_options *ndo,
const u_char *msg_data, u_int hello_len)
{
@ -236,6 +242,8 @@ olsr_print_neighbor(netdissect_options *ndo,
while (hello_len >= sizeof(struct in_addr)) {
if (!ND_TTEST2(*msg_data, sizeof(struct in_addr)))
return (-1);
/* print 4 neighbors per line */
ND_PRINT((ndo, "%s%s", ipaddr_string(ndo, msg_data),
@ -244,6 +252,7 @@ olsr_print_neighbor(netdissect_options *ndo,
msg_data += sizeof(struct in_addr);
hello_len -= sizeof(struct in_addr);
}
return (0);
}
@ -326,6 +335,9 @@ olsr_print(netdissect_options *ndo,
ME_TO_DOUBLE(msgptr.v6->vtime),
EXTRACT_16BITS(msgptr.v6->msg_seq),
msg_len, (msg_len_valid == 0) ? " (invalid)" : ""));
if (!msg_len_valid) {
return;
}
msg_tlen = msg_len - sizeof(struct olsr_msg6);
msg_data = tptr + sizeof(struct olsr_msg6);
@ -354,6 +366,9 @@ olsr_print(netdissect_options *ndo,
ME_TO_DOUBLE(msgptr.v4->vtime),
EXTRACT_16BITS(msgptr.v4->msg_seq),
msg_len, (msg_len_valid == 0) ? " (invalid)" : ""));
if (!msg_len_valid) {
return;
}
msg_tlen = msg_len - sizeof(struct olsr_msg4);
msg_data = tptr + sizeof(struct olsr_msg4);
@ -362,6 +377,8 @@ olsr_print(netdissect_options *ndo,
switch (msg_type) {
case OLSR_HELLO_MSG:
case OLSR_HELLO_LQ_MSG:
if (msg_tlen < sizeof(struct olsr_hello))
goto trunc;
ND_TCHECK2(*msg_data, sizeof(struct olsr_hello));
ptr.hello = (struct olsr_hello *)msg_data;
@ -401,15 +418,21 @@ olsr_print(netdissect_options *ndo,
msg_tlen -= sizeof(struct olsr_hello_link);
hello_len -= sizeof(struct olsr_hello_link);
ND_TCHECK2(*msg_data, hello_len);
if (msg_type == OLSR_HELLO_MSG) {
olsr_print_neighbor(ndo, msg_data, hello_len);
if (olsr_print_neighbor(ndo, msg_data, hello_len) == -1)
goto trunc;
} else {
#if INET6
if (is_ipv6)
olsr_print_lq_neighbor6(ndo, msg_data, hello_len);
else
if (is_ipv6) {
if (olsr_print_lq_neighbor6(ndo, msg_data, hello_len) == -1)
goto trunc;
} else
#endif
olsr_print_lq_neighbor4(ndo, msg_data, hello_len);
{
if (olsr_print_lq_neighbor4(ndo, msg_data, hello_len) == -1)
goto trunc;
}
}
msg_data += hello_len;
@ -419,6 +442,8 @@ olsr_print(netdissect_options *ndo,
case OLSR_TC_MSG:
case OLSR_TC_LQ_MSG:
if (msg_tlen < sizeof(struct olsr_tc))
goto trunc;
ND_TCHECK2(*msg_data, sizeof(struct olsr_tc));
ptr.tc = (struct olsr_tc *)msg_data;
@ -428,14 +453,19 @@ olsr_print(netdissect_options *ndo,
msg_tlen -= sizeof(struct olsr_tc);
if (msg_type == OLSR_TC_MSG) {
olsr_print_neighbor(ndo, msg_data, msg_tlen);
if (olsr_print_neighbor(ndo, msg_data, msg_tlen) == -1)
goto trunc;
} else {
#if INET6
if (is_ipv6)
olsr_print_lq_neighbor6(ndo, msg_data, msg_tlen);
else
if (is_ipv6) {
if (olsr_print_lq_neighbor6(ndo, msg_data, msg_tlen) == -1)
goto trunc;
} else
#endif
olsr_print_lq_neighbor4(ndo, msg_data, msg_tlen);
{
if (olsr_print_lq_neighbor4(ndo, msg_data, msg_tlen) == -1)
goto trunc;
}
}
break;