66 lines
2.3 KiB
Diff
66 lines
2.3 KiB
Diff
Fix CVE-2017-16943:
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https://bugs.exim.org/show_bug.cgi?id=2199
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https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-16943
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Patch copied from upstream source repository:
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https://git.exim.org/exim.git/commit/4090d62a4b25782129cc1643596dc2f6e8f63bde
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From 4090d62a4b25782129cc1643596dc2f6e8f63bde Mon Sep 17 00:00:00 2001
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From: Jeremy Harris <jgh146exb@wizmail.org>
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Date: Fri, 24 Nov 2017 20:22:33 +0000
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Subject: [PATCH] Avoid release of store if there have been later allocations.
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Bug 2199
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---
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doc/doc-txt/ChangeLog | 4 ++++
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src/src/receive.c | 7 ++++---
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2 files changed, 8 insertions(+), 3 deletions(-)
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#diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
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#index e937ba2..a2d9339 100644
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#--- a/doc/doc-txt/ChangeLog
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#+++ b/doc/doc-txt/ChangeLog
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#@@ -59,6 +59,10 @@ JH/30 Fix a logging bug on aarch64: an unsafe routine was previously used for
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# connection in response to HELO" was logged instead of the actual 4xx
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# error for the HELO.
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#
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#+JH/34 Bug 2199: fix a use-after-free while reading smtp input for header lines.
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#+ A crafted sequence of BDAT commands could result in in-use memory beeing
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#+ freed.
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#+
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#
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Exim version 4.89
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-----------------
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diff --git a/src/src/receive.c b/src/src/receive.c
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index 95cf13e..20672db 100644
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--- a/src/receive.c
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+++ b/src/receive.c
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@@ -1772,8 +1772,8 @@ for (;;)
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(and sometimes lunatic messages can have ones that are 100s of K long) we
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call store_release() for strings that have been copied - if the string is at
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the start of a block (and therefore the only thing in it, because we aren't
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- doing any other gets), the block gets freed. We can only do this because we
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- know there are no other calls to store_get() going on. */
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+ doing any other gets), the block gets freed. We can only do this release if
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+ there were no allocations since the once that we want to free. */
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if (ptr >= header_size - 4)
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{
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@@ -1782,9 +1782,10 @@ for (;;)
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header_size *= 2;
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if (!store_extend(next->text, oldsize, header_size))
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{
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+ BOOL release_ok = store_last_get[store_pool] == next->text;
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uschar *newtext = store_get(header_size);
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memcpy(newtext, next->text, ptr);
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- store_release(next->text);
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+ if (release_ok) store_release(next->text);
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next->text = newtext;
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}
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}
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--
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1.9.1
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