1 From: Jeremy Harris <jgh146exb@wizmail.org>
2 Date: Fri, 24 Nov 2017 20:22:33 +0000
3 Subject: Avoid release of store if there have been later allocations. Bug
5 Origin: https://git.exim.org/exim.git/commit/4090d62a4b25782129cc1643596dc2f6e8f63bde
6 Bug: https://bugs.exim.org/show_bug.cgi?id=2199
7 Bug-Debian: https://bugs.debian.org/882648
8 Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-16943
11 diff --git a/src/receive.c b/src/receive.c
12 index 95cf13e1..20672dbe 100644
15 @@ -1772,8 +1772,8 @@ for (;;)
16 (and sometimes lunatic messages can have ones that are 100s of K long) we
17 call store_release() for strings that have been copied - if the string is at
18 the start of a block (and therefore the only thing in it, because we aren't
19 - doing any other gets), the block gets freed. We can only do this because we
20 - know there are no other calls to store_get() going on. */
21 + doing any other gets), the block gets freed. We can only do this release if
22 + there were no allocations since the once that we want to free. */
24 if (ptr >= header_size - 4)
26 @@ -1782,9 +1782,10 @@ for (;;)
28 if (!store_extend(next->text, oldsize, header_size))
30 + BOOL release_ok = store_last_get[store_pool] == next->text;
31 uschar *newtext = store_get(header_size);
32 memcpy(newtext, next->text, ptr);
33 - store_release(next->text);
34 + if (release_ok) store_release(next->text);