Bug #78479 [NEW]: gethostbyname can incorrectly return 0.0.0.0
From: ryan at arctype dot co
Operating system: Ubuntu Linux
PHP version: master-Git-2019-08-30 (Git)
Package: *Network Functions
Bug Type: Bug
Bug description:gethostbyname can incorrectly return 0.0.0.0
Description:
------------
Consider:
<?php echo gethostbyname("www.google.com"); ?>
38.7.248.176
<?php echo gethostbyname("downloads.wordpress.org"); ?>
0.0.0.0
;; ANSWER SECTION:
www.google.com. 229 IN A 216.58.193.196
;; ANSWER SECTION:
downloads.wordpress.org. 300 IN A 198.143.164.250
The DNS on the host is running fine, DNS for downloads.wordpress.org is
ok. We are however running on a dual-stack ipv4/v6 host.
www.google.com has an AAAA record, downloads.wordpress.org does not.
I suspect that gethostbyname() is returning an AAAA record from the
system call to gethostbyname(3), which returns a struct hostent:
struct hostent {
char *h_name; /* official name of host */
char **h_aliases; /* alias list */
int h_addrtype; /* host address type */
int h_length; /* length of address */
char **h_addr_list; /* list of addresses */
}
While the PHP docs explicitly state that PHP's gethostbyname() returns
the IPv4 address, the implementation does not restrict or check if the
system call actually returns an AF_INET h_addrtype instead of AF_INET6,
always assuming a v4 and copying sizeof(in_addr):
https://github.com/php/php-src/blob/master/ext/standard/dns.c#L272
According to the Linux man pages, "The gethostbyname*(),
gethostbyaddr*(), herror(), and hstrerror() functions are obsolete.
Applications should use getaddrinfo(3), getnameinfo(3), and
gai_strerror(3) instead."
"The gethostbyaddr() function returns a structure of type
hostent for the given host address addr of length len and address type
type. Valid address types are AF_INET and
AF_INET6."
This problem has manifested elsewhere in this Wordpress bug report from
a dual-stack host: https://core.trac.wordpress.org/ticket/38291
--
Edit bug report at https://bugs.php.net/bug.php?id=78479&edit=1
--
Fix committed: https://bugs.php.net/fix.php?id=78479&r=fixed
Fixed in release: https://bugs.php.net/fix.php?id=78479&r=alreadyfixed
Need backtrace: https://bugs.php.net/fix.php?id=78479&r=needtrace
Need Reproduce Script: https://bugs.php.net/fix.php?id=78479&r=needscript
Try newer version: https://bugs.php.net/fix.php?id=78479&r=oldversion
Not developer issue: https://bugs.php.net/fix.php?id=78479&r=support
Expected behavior: https://bugs.php.net/fix.php?id=78479&r=notwrong
Not enough info: https://bugs.php.net/fix.php?id=78479&r=notenoughinfo
Submitted twice: https://bugs.php.net/fix.php?id=78479&r=submittedtwice
register_globals: https://bugs.php.net/fix.php?id=78479&r=globals
PHP version support discontinued: https://bugs.php.net/fix.php?id=78479&r=phptooold
Daylight Savings: https://bugs.php.net/fix.php?id=78479&r=dst
IIS Stability: https://bugs.php.net/fix.php?id=78479&r=isapi
Install GNU Sed: https://bugs.php.net/fix.php?id=78479&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=78479&r=float
No Zend Extensions: https://bugs.php.net/fix.php?id=78479&r=nozend
MySQL Configuration Error: https://bugs.php.net/fix.php?id=78479&r=mysqlcfg
Thread (6 messages)
- ryan at arctype dot co