| Summary: | AS: Buffer Overflow when scrubing chars | ||
|---|---|---|---|
| Product: | binutils | Reporter: | Marcel Böhme <boehme.marcel> |
| Component: | gas | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | nickc, thuanpv |
| Priority: | P2 | ||
| Version: | 2.28 | ||
| Target Milestone: | --- | ||
| Host: | Target: | ||
| Build: | Last reconfirmed: | ||
The master branch has been updated by Nick Clifton <nickc@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=69ace2200106348a1b00d509a6a234337c104c17 commit 69ace2200106348a1b00d509a6a234337c104c17 Author: Nick Clifton <nickc@redhat.com> Date: Thu Dec 1 15:20:19 2016 +0000 Fix seg fault attempting to unget an EOF character. PR gas/20898 * app.c (do_scrub_chars): Do not attempt to unget EOF. Hi Marcel, Thanks for reporting this bug. I have checked in a small patch to stop the assembler from attempting to push and end-of-file value back into the input stream, which should fix the bug. Cheers Nick This is CVE-2017-7223 |
Dear all, The following bug was found with AFLFast, a fork of AFL, in a 24 hour fuzzing session on Binutils. Thanks also to Van-Thuan Pham. There is a global buffer overflow (write of size 1) in the assembler for the following execution on Ubuntu 14.04 x86_64 for Binutils v2.26 and in trunk. Interestingly, it does not seg-fault on my machine. $ printf "/" > test $ ./as test ASAN says: ==141249==ERROR: AddressSanitizer: global-buffer-overflow on address 0x00000143fdbf at pc 0x000000407db7 bp 0x7ffd85bdacb0 sp 0x7ffd85bdaca8 WRITE of size 1 at 0x00000143fdbf thread T0 #0 0x407db6 in do_scrub_chars ../../gas/app.c:1193 #1 0x44351b in input_file_give_next_buffer ../../gas/input-file.c:243 #2 0x444a05 in input_scrub_next_buffer ../../gas/input-scrub.c:356 #3 0x460204 in read_a_source_file ../../gas/read.c:835 #4 0x40c417 in perform_an_assembly_pass ../../gas/as.c:1172 #5 0x40c86c in main ../../gas/as.c:1296 #6 0x7fb7630e5f44 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21f44) #7 0x403858 (/home/ubuntu/subjects/binutils-gdb/obj-asan/gas/as-new+0x403858) 0x00000143fdbf is located 55 bytes to the right of global variable 'saved_input_len' defined in '../../gas/app.c:218:15' (0x143fd80) of size 8 0x00000143fdbf is located 1 bytes to the left of global variable 'input_buffer' defined in '../../gas/app.c:219:13' (0x143fdc0) of size 32768 SUMMARY: AddressSanitizer: global-buffer-overflow ../../gas/app.c:1193 in do_scrub_chars Valgrind does not complain. Best regards, - Marcel