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41 lines
1.4 KiB
41 lines
1.4 KiB
From f2ad2cecb55825f7e4409222de1688b9ceebceda Mon Sep 17 00:00:00 2001 |
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From: Simon Kelley <simon@thekelleys.org.uk> |
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Date: Mon, 25 Sep 2017 20:16:50 +0100 |
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Subject: [PATCH 6/9] Security fix, CVE-2017-14495, OOM in DNS response |
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creation. |
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Fix out-of-memory Dos vulnerability. An attacker which can |
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send malicious DNS queries to dnsmasq can trigger memory |
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allocations in the add_pseudoheader function |
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The allocated memory is never freed which leads to a DoS |
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through memory exhaustion. dnsmasq is vulnerable only |
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if one of the following option is specified: |
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--add-mac, --add-cpe-id or --add-subnet. |
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--- |
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src/edns0.c | 8 +++++++- |
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1 file changed, 7 insertions(+), 1 deletion(-) |
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diff --git a/src/edns0.c b/src/edns0.c |
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index eed135e..5bdc133 100644 |
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--- a/src/edns0.c |
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+++ b/src/edns0.c |
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@@ -192,9 +192,15 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l |
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!(p = skip_section(p, |
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ntohs(header->ancount) + ntohs(header->nscount) + ntohs(header->arcount), |
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header, plen))) |
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+ { |
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+ free(buff); |
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return plen; |
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+ } |
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if (p + 11 > limit) |
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- return plen; /* Too big */ |
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+ { |
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+ free(buff); |
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+ return plen; /* Too big */ |
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+ } |
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*p++ = 0; /* empty name */ |
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PUTSHORT(T_OPT, p); |
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PUTSHORT(udp_sz, p); /* max packet length, 512 if not given in EDNS0 header */ |
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-- |
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2.9.5 |
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