Refactor IPv6 parsing
Make it more readable
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/library/x509_crt.c b/library/x509_crt.c
index d094ae0..fc62057 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -2576,23 +2576,42 @@
do {
/* note: allows excess leading 0's, e.g. 1:0002:3:... */
uint16_t group = num_digits = 0;
- for (uint8_t digit; num_digits < 4 && li_cton(*p, digit);
- group <<= 4, group |= digit, ++p, ++num_digits) {
- ;
+ for (uint8_t digit; num_digits < 4; num_digits++) {
+ if (li_cton(*p, digit) == 0) {
+ break;
+ }
+ group = (group << 4) | digit;
+ p++;
}
if (num_digits != 0) {
addr[nonzero_groups++] = MBEDTLS_IS_BIG_ENDIAN ? group :
(group << 8) | (group >> 8);
if (*p == '\0') {
break;
- } else if (*p == '.' && (nonzero_groups != 0 ||
- zero_group_start != -1) &&
- (nonzero_groups < 7) &&
- /* walk back to prior ':', then parse as IPv4-mapped */
- (*--p == ':' || *--p == ':' ||
- *--p == ':' || *--p == ':') &&
- x509_inet_pton_ipv4((const char *) ++p,
- addr + --nonzero_groups) == 0) {
+ } else if (*p == '.') {
+ /* Don't accept IPv4 too early or late */
+ if ((nonzero_groups == 0 && zero_group_start == -1) ||
+ nonzero_groups >= 7) {
+ break;
+ }
+
+ /* Walk back to prior ':', then parse as IPv4-mapped */
+ int steps = 4;
+ do {
+ p--;
+ steps--;
+ } while (*p != ':' && steps > 0);
+
+ if (*p != ':') {
+ break;
+ }
+ p++;
+ nonzero_groups--;
+ if (x509_inet_pton_ipv4((const char *) p,
+ addr + nonzero_groups) != 0) {
+ break;
+ }
+
nonzero_groups += 2;
p = (const unsigned char *) "";
break;
@@ -2600,11 +2619,17 @@
return -1;
}
} else {
- if (zero_group_start != -1 || *p != ':' ||
- ((zero_group_start = nonzero_groups) == 0 &&
- *++p != ':')) {
+ /* Don't accept a second zero group or an invalid delimiter */
+ if (zero_group_start != -1 || *p != ':') {
return -1;
}
+ zero_group_start = nonzero_groups;
+
+ /* Accept a zero group at start, but it has to be a double colon */
+ if (zero_group_start == 0 && *++p != ':') {
+ return -1;
+ }
+
if (p[1] == '\0') {
++p;
break;