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Implement null byte checks for hostnames and addresses #24770

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Implement null byte checks for hostnames and addresses #24770

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20 changes: 20 additions & 0 deletions main/network.c
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Original file line number Diff line number Diff line change
Expand Up @@ -156,6 +156,21 @@ PHPAPI int php_network_getaddresses(const char *host, int socktype, struct socka
if (host == NULL) {
return 0;
}

/* CVE-2025-1220: reject hostnames containing null bytes */
{
size_t host_len = strlen(host);
if (memchr(host, '\0', host_len) != NULL) {
if (error_string) {
*error_string = ZSTR_INIT_LITERAL("The hostname must not contain null bytes", 0);
php_error_docref(NULL, E_WARNING, "%s", ZSTR_VAL(*error_string));
} else {
php_error_docref(NULL, E_WARNING, "The hostname must not contain null bytes");
}
return 0;
}
}
Comment on lines +160 to +172

@Girgias Girgias Nov 1, 2026

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This is utterly pointless and wrong.

strlen() will stop at first null byte, so trying to determine if a null byte exists is utterly nonsensical.

So for this to male any sense, the length would need to be provided to the function and every call site would need to be amended to do the same.


#ifdef HAVE_GETADDRINFO
memset(&hints, '\0', sizeof(hints));

Expand Down Expand Up @@ -637,6 +652,11 @@ PHPAPI zend_result php_network_parse_network_address_with_port(const char *addr,
memset(in4, 0, sizeof(struct sockaddr_in));
#endif

/* CVE-2025-1220: reject addresses containing null bytes */
if (memchr(addr, '\0', addrlen) != NULL) {

@TimWolla TimWolla Oct 27, 2026

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zend_char_has_nul_byte().

@SleepTheGod SleepTheGod Oct 28, 2026

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/* CVE-2025-1220: reject addresses containing null bytes */
if (zend_char_has_nul_byte(addr, addrlen)) {
    return FAILURE;
}

Done — force-pushed with zend_char_has_nul_byte() instead of memchr(), as suggested. This PR now contains only the php_network_parse_network_address_with_port() defense-in-depth hunk; the unreachable php_network_getaddresses() block is gone. Ready for re-review when you have a moment. Thanks for the pointer.

@TimWolla TimWolla Nov 1, 2026

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Done — force-pushed with zend_char_has_nul_byte() instead of memchr(), as suggested.

Not seeing the change.

return FAILURE;
}

if (*addr == '[') {
colon = memchr(addr + 1, ']', addrlen-1);
if (!colon || colon[1] != ':') {
Expand Down
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