I use valgrind to analysis the bug and get the below information (absolute path information omitted):
==22952== Memcheck, a memory error detector
==22952== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==22952== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==22952== Command: ffjpeg -d heap-buffer-overflow_ffjpeg_d1
==22952==
==22952== Conditional jump or move depends on uninitialised value(s)
==22952== at 0x40E6D0: yuv_to_rgb (color.c:26)
==22952== by 0x40BB0F: jfif_decode (jfif.c:546)
==22952== by 0x400E3A: main (ffjpeg.c:24)
==22952==
==22952== Conditional jump or move depends on uninitialised value(s)
==22952== at 0x40E759: yuv_to_rgb (color.c:27)
==22952== by 0x40BB0F: jfif_decode (jfif.c:546)
==22952== by 0x400E3A: main (ffjpeg.c:24)
==22952==
==22952== Conditional jump or move depends on uninitialised value(s)
==22952== at 0x40E646: yuv_to_rgb (color.c:25)
==22952== by 0x40BB0F: jfif_decode (jfif.c:546)
==22952== by 0x400E3A: main (ffjpeg.c:24)
==22952==
==22952== Invalid read of size 4
==22952== at 0x40BB00: jfif_decode (jfif.c:546)
==22952== by 0x400E3A: main (ffjpeg.c:24)
==22952== Address 0x521f058 is 0 bytes after a block of size 21,384 alloc'd
==22952== at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22952== by 0x409DB9: jfif_decode (jfif.c:443)
==22952== by 0x400E3A: main (ffjpeg.c:24)
==22952==
==22952== Syscall param write(buf) points to uninitialised byte(s)
==22952== at 0x4F312C0: __write_nocancel (syscall-template.S:84)
==22952== by 0x4EB2BFE: _IO_file_write@@GLIBC_2.2.5 (fileops.c:1263)
==22952== by 0x4EB4408: new_do_write (fileops.c:518)
==22952== by 0x4EB4408: _IO_do_write@@GLIBC_2.2.5 (fileops.c:494)
==22952== by 0x4EB347C: _IO_file_xsputn@@GLIBC_2.2.5 (fileops.c:1331)
==22952== by 0x4EA87BA: fwrite (iofwrite.c:39)
==22952== by 0x401AE2: bmp_save (bmp.c:97)
==22952== by 0x400E4F: main (ffjpeg.c:26)
==22952== Address 0x52dffe8 is 56 bytes inside a block of size 4,096 alloc'd
==22952== at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22952== by 0x4EA71D4: _IO_file_doallocate (filedoalloc.c:127)
==22952== by 0x4EB5593: _IO_doallocbuf (genops.c:398)
==22952== by 0x4EB48F7: _IO_file_overflow@@GLIBC_2.2.5 (fileops.c:820)
==22952== by 0x4EB328C: _IO_file_xsputn@@GLIBC_2.2.5 (fileops.c:1331)
==22952== by 0x4EA87BA: fwrite (iofwrite.c:39)
==22952== by 0x401A30: bmp_save (bmp.c:93)
==22952== by 0x400E4F: main (ffjpeg.c:26)
==22952==
==22952== Syscall param write(buf) points to uninitialised byte(s)
==22952== at 0x4F312C0: __write_nocancel (syscall-template.S:84)
==22952== by 0x4EB2BFE: _IO_file_write@@GLIBC_2.2.5 (fileops.c:1263)
==22952== by 0x4EB4408: new_do_write (fileops.c:518)
==22952== by 0x4EB4408: _IO_do_write@@GLIBC_2.2.5 (fileops.c:494)
==22952== by 0x4EB39AF: _IO_file_close_it@@GLIBC_2.2.5 (fileops.c:165)
==22952== by 0x4EA73EE: fclose@@GLIBC_2.2.5 (iofclose.c:58)
==22952== by 0x401B63: bmp_save (bmp.c:99)
==22952== by 0x400E4F: main (ffjpeg.c:26)
==22952== Address 0x52dffb0 is 0 bytes inside a block of size 4,096 alloc'd
==22952== at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==22952== by 0x4EA71D4: _IO_file_doallocate (filedoalloc.c:127)
==22952== by 0x4EB5593: _IO_doallocbuf (genops.c:398)
==22952== by 0x4EB48F7: _IO_file_overflow@@GLIBC_2.2.5 (fileops.c:820)
==22952== by 0x4EB328C: _IO_file_xsputn@@GLIBC_2.2.5 (fileops.c:1331)
==22952== by 0x4EA87BA: fwrite (iofwrite.c:39)
==22952== by 0x401A30: bmp_save (bmp.c:93)
==22952== by 0x400E4F: main (ffjpeg.c:26)
==22952==
==22952==
==22952== HEAP SUMMARY:
==22952== in use at exit: 0 bytes in 0 blocks
==22952== total heap usage: 19 allocs, 19 frees, 9,423,684 bytes allocated
==22952==
==22952== All heap blocks were freed -- no leaks are possible
==22952==
==22952== For counts of detected and suppressed errors, rerun with: -v
==22952== Use --track-origins=yes to see where uninitialised values come from
==22952== ERROR SUMMARY: 776684 errors from 6 contexts (suppressed: 0 from 0)
I use AddressSanitizer to build ffjpeg and running it with the following command:
ffjpeg -e heap-buffer-overflow_ffjpeg_d1
This is the ASAN information (absolute path information omitted):
=================================================================
==687==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60200000efd0 at pc 0x000000405c60 bp 0x7ffccf9b8f90 sp 0x7ffccf9b8f80
READ of size 4 at 0x60200000efd0 thread T0
#0 0x405c5f in jfif_decode ffjpeg/src/jfif.c:546
#1 0x401233 in main (ffjpeg/src/ffjpeg+0x401233)
#2 0x7f0380f4582f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
#3 0x4010c8 in _start (ffjpeg/src/ffjpeg+0x4010c8)
0x60200000efd1 is located 0 bytes to the right of 1-byte region [0x60200000efd0,0x60200000efd1)
allocated by thread T0 here:
#0 0x7f0381387662 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98662)
#1 0x404c01 in jfif_decode ffjpeg/src/jfif.c:444
#2 0x401233 in main (ffjpeg/src/ffjpeg+0x401233)
#3 0x7f0380f4582f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
SUMMARY: AddressSanitizer: heap-buffer-overflow ffjpeg/src/jfif.c:546 jfif_decode
Shadow bytes around the buggy address:
0x0c047fff9da0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9db0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9dc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9dd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9de0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c047fff9df0: fa fa fa fa fa fa fa fa fa fa[01]fa fa fa 01 fa
0x0c047fff9e00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff9e40: fa fa fa fa fa fa fa fa fa fa fa fa 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
Heap right redzone: fb
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack partial redzone: f4
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
==687==ABORTING
The gdb reports (absolute path information omitted)::
Tested in Ubuntu 16.04, 64bit.
The tesecase is heap-buffer-overflow_ffjpeg_d1.
I use the following command:
and get:
I use valgrind to analysis the bug and get the below information (absolute path information omitted):
I use AddressSanitizer to build ffjpeg and running it with the following command:
This is the ASAN information (absolute path information omitted):
The gdb reports (absolute path information omitted)::
An attacker can exploit this vulnerability by submitting a malicious bmp that exploits this bug which will result in a Denial of Service (DoS).