glibc/glibc-rh1332914-5.patch
Florian Weimer 217d136f41 Resolves: #1332914
April 2016 nss_dns hardening
2016-05-06 17:02:34 +02:00

58 lines
1.5 KiB
Diff

commit a12f9431b3808e78b9ed397e4fce7de69410d94d
Author: Florian Weimer <fweimer@redhat.com>
Date: Wed Apr 27 17:15:57 2016 +0200
nss_dns: Skip over non-PTR records in the netent code [BZ #19868]
This requires additional checks for the RDATA length and the
availability of record metadata.
Index: b/resolv/nss_dns/dns-network.c
===================================================================
--- a/resolv/nss_dns/dns-network.c
+++ b/resolv/nss_dns/dns-network.c
@@ -345,10 +345,23 @@ getanswer_r (const querybuf *answer, int
if (n < 0 || res_dnok (bp) == 0)
break;
cp += n;
+
+ if (end_of_message - cp < 10)
+ {
+ __set_h_errno (NO_RECOVERY);
+ return NSS_STATUS_UNAVAIL;
+ }
+
GETSHORT (type, cp);
GETSHORT (class, cp);
cp += INT32SZ; /* TTL */
- GETSHORT (n, cp);
+ uint16_t rdatalen;
+ GETSHORT (rdatalen, cp);
+ if (end_of_message - cp < rdatalen)
+ {
+ __set_h_errno (NO_RECOVERY);
+ return NSS_STATUS_UNAVAIL;
+ }
if (class == C_IN && type == T_PTR)
{
@@ -370,7 +383,7 @@ getanswer_r (const querybuf *answer, int
cp += n;
return NSS_STATUS_UNAVAIL;
}
- cp += n;
+ cp += rdatalen;
if (alias_pointer + 2 < &net_data->aliases[MAX_NR_ALIASES])
{
*alias_pointer++ = bp;
@@ -381,6 +394,9 @@ getanswer_r (const querybuf *answer, int
++have_answer;
}
}
+ else
+ /* Skip over unknown record data. */
+ cp += rdatalen;
}
if (have_answer)