217d136f41
April 2016 nss_dns hardening
58 lines
1.5 KiB
Diff
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)
|