mirror/lwip
1
0
Fork 0
mirror of https://github.com/lwip-tcpip/lwip.git synced 2024-11-18 20:10:53 +00:00
Code Issues Packages Projects Releases Wiki Activity

Fix out-of-bound access in ip6addr_ntoa_r()

Browse Source 
When detecting that zero is single, code reads the next group even if it is last group.

If next bytes are not-null, last zero is not omitted.

If next bytes are null, last zero is omitted, but since there are no groups left,
finishing ':' will not be written, resulting in invalid address.

This commit turns off non-single zero check for the last group.
This commit is contained in:
Sergey Fionov 2024-03-07 11:02:37 +02:00
parent 0a0452b2c3
commit 07ec589dd3
2 changed files with 15 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
src/core/ipv6/ip6_addr.c
View File

@ -270,15 +270,16 @@ ip6addr_ntoa_r(const ip6_addr_t *addr, char *buf, int buflen)
/* Check for empty block. */
if (current_block_value == 0) {
if (current_block_index == 7 && empty_block_flag == 1) {
/* special case, we must render a ':' for the last block. */
buf[i++] = ':';
if (i >= buflen) {
return NULL;
if (current_block_index == 7) {
if (empty_block_flag == 1) {
/* special case, we must render a ':' for the last block. */
buf[i++] = ':';
if (i >= buflen) {
return NULL;
}
break;
}
break;
}
if (empty_block_flag == 0) {
} else if (empty_block_flag == 0) {
/* generate empty block "::", but only if more than one contiguous zero block,
* according to current formatting suggestions RFC 5952. */
next_block_value = lwip_htonl(addr->addr[(current_block_index + 1) >> 1]);

9
test/unit/ip6/test_ip6.c
View File

@ -224,15 +224,18 @@ END_TEST
struct test_addr_and_str {
ip_addr_t addr;
u32_t bytes_after;
const char *str;
};
START_TEST(test_ip6_ntoa)
{
struct test_addr_and_str tests[] = {
{IPADDR6_INIT_HOST(0xfe800000, 0x00000000, 0xb2a1a2ff, 0xfea3a4a5), "FE80::B2A1:A2FF:FEA3:A4A5"}, /* test shortened zeros */
{IPADDR6_INIT_HOST(0xfe800000, 0xff000000, 0xb2a1a2ff, 0xfea3a4a5), "FE80:0:FF00:0:B2A1:A2FF:FEA3:A4A5"}, /* don't omit single zero blocks */
{IPADDR6_INIT_HOST(0xfe800000, 0xff000000, 0xb2000000, 0x0000a4a5), "FE80:0:FF00:0:B200::A4A5"}, /* omit longest zero block */
{IPADDR6_INIT_HOST(0xfe800000, 0x00000000, 0xb2a1a2ff, 0xfea3a4a5), 0, "FE80::B2A1:A2FF:FEA3:A4A5"}, /* test shortened zeros */
{IPADDR6_INIT_HOST(0xfe800000, 0xff000000, 0xb2a1a2ff, 0xfea3a4a5), 0, "FE80:0:FF00:0:B2A1:A2FF:FEA3:A4A5"}, /* don't omit single zero blocks */
{IPADDR6_INIT_HOST(0xfe800000, 0xff000000, 0xb2000000, 0x0000a4a5), 0, "FE80:0:FF00:0:B200::A4A5"}, /* omit longest zero block */
{IPADDR6_INIT_HOST(0x20010db8, 0x00010002, 0x00030004, 0x00050000), 0, "2001:DB8:1:2:3:4:5:0"}, /* do not omit last zero due to out-of-bounds bug */
{IPADDR6_INIT_HOST(0x20010db8, 0x00010002, 0x00030004, 0x00050000), 1, "2001:DB8:1:2:3:4:5:0"}, /* do not omit last zero due to out-of-bounds bug */
};
char buf[128];
char *str;