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[PATCH] nss_dns: Adjust ns_name_ntop failure handling in getnetby*
- From: Florian Weimer <fweimer at redhat dot com>
- To: libc-alpha at sourceware dot org
- Date: Fri, 08 Mar 2019 21:46:12 +0100
- Subject: [PATCH] nss_dns: Adjust ns_name_ntop failure handling in getnetby*
If the function fails, the output buffer is not large enough. The
function does not fail for any other reason.
2019-03-08 Florian Weimer <fweimer@redhat.com>
* resolv/nss_dns/dns-network.c (getanswer_r): On ns_name_ntop
failure, the buffer is always too small.
diff --git a/resolv/nss_dns/dns-network.c b/resolv/nss_dns/dns-network.c
index 68266d57c9..9b75ac8233 100644
--- a/resolv/nss_dns/dns-network.c
+++ b/resolv/nss_dns/dns-network.c
@@ -324,19 +324,14 @@ getanswer_r (const querybuf *answer, int anslen, struct netent *result,
{
int n = __ns_name_unpack (answer->buf, end_of_message, cp,
packtmp, sizeof packtmp);
- if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
- {
- if (errno == EMSGSIZE)
- goto too_small;
-
- n = -1;
- }
-
- if (n > 0 && bp[0] == '.')
- bp[0] = '\0';
-
if (n < 0)
goto bad_message;
+ if (__ns_name_ntop (packtmp, bp, linebuflen) < 0)
+ goto too_small;
+
+ if (bp[0] == '.')
+ bp[0] = '\0';
+
cp += n;
if (end_of_message - cp < 10)
@@ -355,16 +350,11 @@ getanswer_r (const querybuf *answer, int anslen, struct netent *result,
{
n = __ns_name_unpack (answer->buf, end_of_message, cp,
packtmp, sizeof packtmp);
- if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
- {
- if (errno == EMSGSIZE)
- goto too_small;
-
- n = -1;
- }
-
if (n < 0)
goto bad_message;
+ if (__ns_name_ntop (packtmp, bp, linebuflen) < 0)
+ goto too_small;
+
cp += rdatalen;
if (alias_pointer + 2 < &net_data->aliases[MAX_NR_ALIASES])
{