34 lines
1.5 KiB
Diff
34 lines
1.5 KiB
Diff
From b897ca43ac100d326d118e5877da710eb7f836f9 Mon Sep 17 00:00:00 2001
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From: traffic-millions <60914101+traffic-millions@users.noreply.github.com>
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Date: Tue, 3 Mar 2020 11:15:48 +0800
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Subject: [PATCH 11/11] avahi_dns_packet_consume_uint32: fix potential
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undefined behavior
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avahi_dns_packet_consume_uint32 left shifts uint8_t values by 8, 16 and 24 bits to combine them into a 32-bit value. This produces an undefined behavior warning with gcc -fsanitize when fed input values of 128 or 255 however in testing no actual unexpected behavior occurs in practice and the 32-bit uint32_t is always correctly produced as the final value is immediately stored into a uint32_t and the compiler appears to handle this "correctly".
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Cast the intermediate values to uint32_t to prevent this warning and ensure the intended result is explicit.
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Closes: #267
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Closes: #268
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Reference: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=19304
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---
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avahi-core/dns.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/avahi-core/dns.c b/avahi-core/dns.c
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index 7c38f42..d793b76 100644
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--- a/avahi-core/dns.c
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+++ b/avahi-core/dns.c
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@@ -455,7 +455,7 @@ int avahi_dns_packet_consume_uint32(AvahiDnsPacket *p, uint32_t *ret_v) {
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return -1;
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d = (uint8_t*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex);
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- *ret_v = (d[0] << 24) | (d[1] << 16) | (d[2] << 8) | d[3];
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+ *ret_v = ((uint32_t)d[0] << 24) | ((uint32_t)d[1] << 16) | ((uint32_t)d[2] << 8) | (uint32_t)d[3];
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p->rindex += sizeof(uint32_t);
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return 0;
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--
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2.25.2
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