Brad Bishop | 1a4b7ee | 2018-12-16 17:11:34 -0800 | [diff] [blame] | 1 | From 45a0eaf77022963d639d6d19871dbab7b79703fc Mon Sep 17 00:00:00 2001 |
| 2 | From: Alan Modra <amodra@gmail.com> |
| 3 | Date: Tue, 23 Oct 2018 19:02:06 +1030 |
| 4 | Subject: [PATCH] PR23806, NULL pointer dereference in merge_strings |
| 5 | |
| 6 | PR 23806 |
| 7 | * merge.c (_bfd_add_merge_section): Don't attempt to merge |
| 8 | sections with ridiculously large alignments. |
| 9 | |
| 10 | Upstream-Status: Backport |
| 11 | CVE: CVE-2018-18606 |
| 12 | Signed-off-by: Zhixiong Chi <zhixiong.chi@windriver.com> |
| 13 | --- |
| 14 | bfd/ChangeLog | 6 ++++++ |
| 15 | bfd/merge.c | 15 +++++++++++---- |
| 16 | 2 files changed, 17 insertions(+), 4 deletions(-) |
| 17 | |
Brad Bishop | 1a4b7ee | 2018-12-16 17:11:34 -0800 | [diff] [blame] | 18 | --- a/bfd/merge.c |
| 19 | +++ b/bfd/merge.c |
| 20 | @@ -24,6 +24,7 @@ |
| 21 | as used in ELF SHF_MERGE. */ |
| 22 | |
| 23 | #include "sysdep.h" |
| 24 | +#include <limits.h> |
| 25 | #include "bfd.h" |
| 26 | #include "elf-bfd.h" |
| 27 | #include "libbfd.h" |
Brad Bishop | 977dc1a | 2019-02-06 16:01:43 -0500 | [diff] [blame] | 28 | @@ -385,12 +386,18 @@ _bfd_add_merge_section (bfd *abfd, void |
Brad Bishop | 1a4b7ee | 2018-12-16 17:11:34 -0800 | [diff] [blame] | 29 | return TRUE; |
| 30 | } |
| 31 | |
| 32 | - align = sec->alignment_power; |
| 33 | - if ((sec->entsize < (unsigned) 1 << align |
| 34 | +#ifndef CHAR_BIT |
| 35 | +#define CHAR_BIT 8 |
| 36 | +#endif |
| 37 | + if (sec->alignment_power >= sizeof (align) * CHAR_BIT) |
| 38 | + return TRUE; |
| 39 | + |
| 40 | + align = 1u << sec->alignment_power; |
| 41 | + if ((sec->entsize < align |
| 42 | && ((sec->entsize & (sec->entsize - 1)) |
| 43 | || !(sec->flags & SEC_STRINGS))) |
| 44 | - || (sec->entsize > (unsigned) 1 << align |
| 45 | - && (sec->entsize & (((unsigned) 1 << align) - 1)))) |
| 46 | + || (sec->entsize > align |
| 47 | + && (sec->entsize & (align - 1)))) |
| 48 | { |
| 49 | /* Sanity check. If string character size is smaller than |
| 50 | alignment, then we require character size to be a power |