From 9b57c1c1e4c6889f47b200bcefe77f16becd2095 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Mon, 18 Nov 2002 04:10:15 +0000 Subject: 2002-11-14 Paul Eggert * resolv/nss_dns/dns-network.c (getanswer_r): Check for buffer overflow when skipping the question part and when unpacking aliases. --- resolv/nss_dns/dns-network.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) (limited to 'resolv/nss_dns') diff --git a/resolv/nss_dns/dns-network.c b/resolv/nss_dns/dns-network.c index 5956c84382..fdab996837 100644 --- a/resolv/nss_dns/dns-network.c +++ b/resolv/nss_dns/dns-network.c @@ -283,7 +283,15 @@ getanswer_r (const querybuf *answer, int anslen, struct netent *result, /* Skip the question part. */ while (question_count-- > 0) - cp += __dn_skipname (cp, end_of_message) + QFIXEDSZ; + { + int n = __dn_skipname (cp, end_of_message); + if (n < 0 || end_of_message - (cp + n) < QFIXEDSZ) + { + __set_h_errno (NO_RECOVERY); + return NSS_STATUS_UNAVAIL; + } + cp += n + QFIXEDSZ; + } alias_pointer = result->n_aliases = &net_data->aliases[0]; *alias_pointer = NULL; @@ -344,12 +352,15 @@ getanswer_r (const querybuf *answer, int anslen, struct netent *result, return NSS_STATUS_UNAVAIL; } cp += n; - *alias_pointer++ = bp; - n = strlen (bp) + 1; - bp += n; - linebuflen -= n; - result->n_addrtype = class == C_IN ? AF_INET : AF_UNSPEC; - ++have_answer; + if (alias_pointer + 2 < &net_data->aliases[MAX_NR_ALIASES]) + { + *alias_pointer++ = bp; + n = strlen (bp) + 1; + bp += n; + linebuflen -= n; + result->n_addrtype = class == C_IN ? AF_INET : AF_UNSPEC; + ++have_answer; + } } } -- cgit 1.4.1