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f58705b77e
This is a backport from the dnsmasq master which should fix a bug which
could cause a crash in dnsmasq.
I saw the following crashes in my log:
[522413.117215] do_page_fault(): sending SIGSEGV to dnsmasq for invalid read access from 2a001450
[522413.124464] epc = 004197f1 in dnsmasq[400000+23000]
[522413.129459] ra = 004197ef in dnsmasq[400000+23000]
This is happening in blockdata_write() when block->next is
dereferenced, but I am not sure if this is related to this problem or if
this is a different problem. I am unable to reproduce this problem.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
(cherry picked from commit 414d054138)
36 lines
1.4 KiB
Diff
36 lines
1.4 KiB
Diff
From e710c34469af4378c2db6fa0b0be88313adcb68f Mon Sep 17 00:00:00 2001
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From: Alin Nastac <alin.nastac@gmail.com>
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Date: Mon, 30 Sep 2019 15:30:26 +0100
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Subject: [PATCH] Fix crash when negative SRV response over TCP gets stored in
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LRU cache entry.
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Patch extended to receive side of pipe by SRK.
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---
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src/cache.c | 8 ++++++--
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1 file changed, 6 insertions(+), 2 deletions(-)
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--- a/src/cache.c
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+++ b/src/cache.c
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@@ -665,7 +665,11 @@ void cache_end_insert(void)
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if (flags & (F_IPV4 | F_IPV6 | F_DNSKEY | F_DS | F_SRV))
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read_write(daemon->pipe_to_parent, (unsigned char *)&new_chain->addr, sizeof(new_chain->addr), 0);
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if (flags & F_SRV)
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- blockdata_write(new_chain->addr.srv.target, new_chain->addr.srv.targetlen, daemon->pipe_to_parent);
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+ {
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+ /* A negative SRV entry is possible and has no data, obviously. */
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+ if (!(flags & F_NEG))
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+ blockdata_write(new_chain->addr.srv.target, new_chain->addr.srv.targetlen, daemon->pipe_to_parent);
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+ }
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#ifdef HAVE_DNSSEC
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if (flags & F_DNSKEY)
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{
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@@ -737,7 +741,7 @@ int cache_recv_insert(time_t now, int fd
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if (!read_write(fd, (unsigned char *)&addr, sizeof(addr), 1))
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return 0;
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- if (flags & F_SRV && !(addr.srv.target = blockdata_read(fd, addr.srv.targetlen)))
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+ if ((flags & F_SRV) && !(flags & F_NEG) && !(addr.srv.target = blockdata_read(fd, addr.srv.targetlen)))
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return 0;
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#ifdef HAVE_DNSSEC
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