Subject: Re: bug#34142: AddressSanitizer reported heap-buffer-overflow

From: Assaf Gordon <[email-masked]>
Date: Sun, 20 Jan 2019 02:14:10 -0700

(forwarding to gnulib)

Hello,

Hongxu Chen reported a heap-buffer-overflow in gnulib's regexec code.

It can be reproduced with current sed using:

      git clone git://git.sv.gnu.org/sed.git
      cd sed
      ./bootstrap && ./configure
      make build-asan

      echo 00000000000000000000000000 | ./sed/sed -E -e 's/(.*)*\1//'

The above 'sed' invocation is a simplified variation of Hongxu's report.

Details below:

On 2019-01-19 11:09 p.m., Hongxu Chen wrote:
> 
>     =================================================================
> ==13920==ERROR: AddressSanitizer: heap-buffer-overflow on address
> 0x606000000233 at pc 0x0000004b4136 bp 0x7ffc475e3930 sp 0x7ffc475e30e0
> READ of size 26 at 0x606000000233 thread T0
>      #0 0x4b4135 in __interceptor_memcmp.part.283
> (/home/hongxu/FOT/sed-O0/install/bin/sed+0x4b4135)
>      #1 0x5b274c in proceed_next_node
> /home/hongxu/FOT/sed-O0/./lib/regexec.c:1296:9
>      #2 0x597a4c in set_regs /home/hongxu/FOT/sed-O0/./lib/regexec.c:1453:18
>      #3 0x569a4f in re_search_internal
> /home/hongxu/FOT/sed-O0/./lib/regexec.c:864:10
>      #4 0x56acd7 in re_search_stub
> /home/hongxu/FOT/sed-O0/./lib/regexec.c:425:12
>      #5 0x56b061 in rpl_re_search
> /home/hongxu/FOT/sed-O0/./lib/regexec.c:289:10
>      #6 0x52f572 in match_regex /home/hongxu/FOT/sed-O0/sed/regexp.c:358:11
>      #7 0x5292d1 in do_subst /home/hongxu/FOT/sed-O0/sed/execute.c:1015:8
>      #8 0x5233a2 in execute_program
> /home/hongxu/FOT/sed-O0/sed/execute.c:1543:15
>      #9 0x520cba in process_files
> /home/hongxu/FOT/sed-O0/sed/execute.c:1680:16
>      #10 0x5300dc in main /home/hongxu/FOT/sed-O0/sed/sed.c:382:17
>      #11 0x7f1dc2297b96 in __libc_start_main
> /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:310
>      #12 0x41b219 in _start
> (/home/hongxu/FOT/sed-O0/install/bin/sed+0x41b219)
> 
> 0x606000000233 is located 0 bytes to the right of 51-byte region
> [0x606000000200,0x606000000233)
> allocated by thread T0 here:
>      #0 0x4db0d0 in malloc (/home/hongxu/FOT/sed-O0/install/bin/sed+0x4db0d0)
>      #1 0x5624f4 in xmalloc /home/hongxu/FOT/sed-O0/lib/xmalloc.c:41:13
>      #2 0x5627c4 in xzalloc /home/hongxu/FOT/sed-O0/lib/xmalloc.c:86:18
>      #3 0x520e16 in line_init /home/hongxu/FOT/sed-O0/sed/execute.c:281:15
>      #4 0x5209ad in process_files
> /home/hongxu/FOT/sed-O0/sed/execute.c:1654:3
>      #5 0x5300dc in main /home/hongxu/FOT/sed-O0/sed/sed.c:382:17
>      #6 0x7f1dc2297b96 in __libc_start_main
> /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:310
> 
> SUMMARY: AddressSanitizer: heap-buffer-overflow
> (/home/hongxu/FOT/sed-O0/install/bin/sed+0x4b4135) in
> __interceptor_memcmp.part.283
> Shadow bytes around the buggy address:
>    0x0c0c7fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>    0x0c0c7fff8000: fa fa fa fa fd fd fd fd fd fd fd fa fa fa fa fa
>    0x0c0c7fff8010: fd fd fd fd fd fd fd fa fa fa fa fa fd fd fd fd
>    0x0c0c7fff8020: fd fd fd fd fa fa fa fa fd fd fd fd fd fd fd fa
>    0x0c0c7fff8030: fa fa fa fa fd fd fd fd fd fd fd fa fa fa fa fa
> =>0x0c0c7fff8040: 00 00 00 00 00 00[03]fa fa fa fa fa 00 00 00 00
>    0x0c0c7fff8050: 00 00 03 fa fa fa fa fa 00 00 00 00 00 00 00 00
>    0x0c0c7fff8060: fa fa fa fa fd fd fd fd fd fd fd fa fa fa fa fa
>    0x0c0c7fff8070: 00 00 00 00 00 00 00 fa fa fa fa fa 00 00 00 00
>    0x0c0c7fff8080: 00 00 00 fa fa fa fa fa fd fd fd fd fd fd fd fd
>    0x0c0c7fff8090: fa fa fa fa 00 00 00 00 00 00 00 00 fa fa fa fa
> Shadow byte legend (one shadow byte represents 8 application bytes):
>    Addressable:           00
>    Partially addressable: 01 02 03 04 05 06 07
>    Heap left redzone:       fa
>    Freed heap region:       fd
>    Stack left redzone:      f1
>    Stack mid redzone:       f2
>    Stack right redzone:     f3
>    Stack after return:      f5
>    Stack use after scope:   f8
>    Global redzone:          f9
>    Global init order:       f6
>    Poisoned by user:        f7
>    Container overflow:      fc
>    Array cookie:            ac
>    Intra object redzone:    bb
>    ASan internal:           fe
>    Left alloca redzone:     ca
>    Right alloca redzone:    cb
> ==13920==ABORTING