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>
(cherry picked from commit c79327bf00)
This commit is contained in:
Florian Weimer 2022-08-30 10:02:49 +02:00
parent bffc33e90e
commit 3c9b4004e2
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;
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

View File

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