| From bd68ae1271598e8fdc72f2adb457e6882604582d Mon Sep 17 00:00:00 2001 |
| From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com> |
| Date: Thu, 22 Feb 2018 16:39:43 +0100 |
| Subject: [PATCH] Fix a heap-buffer-overflow in find_archive() |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| rw_buffer has allocated rw_base_size bytes. But subsequend fgets() in |
| find_archive() reads up-to BUFSIZ bytes. |
| |
| On my system, BUFSIZ is 8192. rw_base_size is usually equaled to |
| a memory page size, 4096 on my system. Thus find_archive() can write |
| beyonded allocated memmory for rw_buffer array: |
| |
| $ valgrind -- ./unshar /tmp/id\:000000\,sig\:06\,src\:000005+000030\,op\:splice\,rep\:4 |
| ==30582== Memcheck, a memory error detector |
| ==30582== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. |
| ==30582== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info |
| ==30582== Command: ./unshar /tmp/id:000000,sig:06,src:000005+000030,op:splice,rep:4 |
| ==30582== |
| ==30582== Invalid write of size 1 |
| ==30582== at 0x4EAB480: _IO_getline_info (in /usr/lib64/libc-2.27.so) |
| ==30582== by 0x4EB47C2: fgets_unlocked (in /usr/lib64/libc-2.27.so) |
| ==30582== by 0x10BF60: fgets_unlocked (stdio2.h:320) |
| ==30582== by 0x10BF60: find_archive (unshar.c:243) |
| ==30582== by 0x10BF60: unshar_file (unshar.c:379) |
| ==30582== by 0x10BCCC: validate_fname (unshar-opts.c:604) |
| ==30582== by 0x10BCCC: main (unshar-opts.c:639) |
| ==30582== Address 0x523a790 is 0 bytes after a block of size 4,096 alloc'd |
| ==30582== at 0x4C2DBBB: malloc (vg_replace_malloc.c:299) |
| ==30582== by 0x10C670: init_unshar (unshar.c:450) |
| ==30582== by 0x10BC55: main (unshar-opts.c:630) |
| |
| This was reported in |
| <http://lists.gnu.org/archive/html/bug-gnu-utils/2018-02/msg00004.html>. |
| |
| CVE: CVE-2018-1000097 |
| Upstream-Status: no upstream [http://lists.gnu.org/archive/html/bug-gnu-utils/2018-02/msg00004.html] |
| Signed-off-by: Petr Písař <ppisar@redhat.com> |
| Signed-off-by: Sinan Kaya <okaya@kernel.org> |
| --- |
| src/unshar.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/src/unshar.c b/src/unshar.c |
| index 80bc3a9..0fc3773 100644 |
| --- a/src/unshar.c |
| +++ b/src/unshar.c |
| @@ -240,7 +240,7 @@ find_archive (char const * name, FILE * file, off_t start) |
| off_t position = ftello (file); |
| |
| /* Read next line, fail if no more and no previous process. */ |
| - if (!fgets (rw_buffer, BUFSIZ, file)) |
| + if (!fgets (rw_buffer, rw_base_size, file)) |
| { |
| if (!start) |
| error (0, 0, _("Found no shell commands in %s"), name); |
| -- |
| 2.19.0 |
| |