resolv: Add internal __res_binary_hnok function

During package parsing, only the binary representation is available,
and it is convenient to check that directly for conformance with host
name requirements.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
This commit is contained in:
Florian Weimer 2022-08-30 10:02:49 +02:00
parent 87aa98aa80
commit c79327bf00
2 changed files with 12 additions and 5 deletions

View file

@ -70,5 +70,8 @@ libc_hidden_proto (__libc_res_nameinquery)
extern __typeof (__res_queriesmatch) __libc_res_queriesmatch; extern __typeof (__res_queriesmatch) __libc_res_queriesmatch;
libc_hidden_proto (__libc_res_queriesmatch) libc_hidden_proto (__libc_res_queriesmatch)
/* Variant of res_hnok which operates on binary (but uncompressed) names. */
bool __res_binary_hnok (const unsigned char *dn) attribute_hidden;
# endif /* _RESOLV_H_ && !_ISOMAC */ # endif /* _RESOLV_H_ && !_ISOMAC */
#endif #endif

View file

@ -138,6 +138,12 @@ binary_leading_dash (const unsigned char *dn)
return dn[0] > 0 && dn[1] == '-'; return dn[0] > 0 && dn[1] == '-';
} }
bool
__res_binary_hnok (const unsigned char *dn)
{
return !binary_leading_dash (dn) && binary_hnok (dn);
}
/* Return 1 if res_hnok is a valid host name. Labels must only /* Return 1 if res_hnok is a valid host name. Labels must only
contain [0-9a-zA-Z_-] characters, and the name must not start with contain [0-9a-zA-Z_-] characters, and the name must not start with
a '-'. The latter is to avoid confusion with program options. */ a '-'. The latter is to avoid confusion with program options. */
@ -145,11 +151,9 @@ int
___res_hnok (const char *dn) ___res_hnok (const char *dn)
{ {
unsigned char buf[NS_MAXCDNAME]; unsigned char buf[NS_MAXCDNAME];
if (!printable_string (dn) return (printable_string (dn)
|| __ns_name_pton (dn, buf, sizeof (buf)) < 0 && __ns_name_pton (dn, buf, sizeof (buf)) >= 0
|| binary_leading_dash (buf)) && __res_binary_hnok (buf));
return 0;
return binary_hnok (buf);
} }
versioned_symbol (libc, ___res_hnok, res_hnok, GLIBC_2_34); versioned_symbol (libc, ___res_hnok, res_hnok, GLIBC_2_34);
versioned_symbol (libc, ___res_hnok, __libc_res_hnok, GLIBC_PRIVATE); versioned_symbol (libc, ___res_hnok, __libc_res_hnok, GLIBC_PRIVATE);