New submission from Daniel Kang <[email protected]>:

For maxval = 0, ffmpeg crashes with SIGPE on pgm files. There is a check for
maxval <= 0, but it is not checked again after maxval is potentially set again.
The patch attached adds a check for that.

gdb run:
(gdb) r -i ../fuzzed.pgm del.jpg
Starting program: ffmpeg/ffmpeg_g -i ../fuzzed.pgm del.jpg
[Thread debugging using libthread_db enabled]
FFmpeg version git-1fb4c1f, Copyright (c) 2000-2011 the FFmpeg developers
  built on Jan  9 2011 14:47:50 with gcc 4.4.5
  configuration: --enable-gpl
  libavutil     50.36. 0 / 50.36. 0
  libavcore      0.16. 0 /  0.16. 0
  libavcodec    52.108. 0 / 52.108. 0
  libavformat   52.92. 0 / 52.92. 0
  libavdevice   52. 2. 3 / 52. 2. 3
  libavfilter    1.72. 0 /  1.72. 0
  libswscale     0.12. 0 /  0.12. 0

Program received signal SIGFPE, Arithmetic exception.
0x00000000006c61b3 in pnm_decode_frame (avctx=0x1205260, data=<value optimized
out>, data_size=<value optimized out>, avpkt=<value optimized out>)
    at libavcodec/pnmdec.c:121
121                     unsigned int j, f = (255 * 128 + s->maxval / 2) / 
s->maxval;
(gdb) bt
#0  0x00000000006c61b3 in pnm_decode_frame (avctx=0x1205260, data=<value
optimized out>, data_size=<value optimized out>, avpkt=<value optimized out>)
    at libavcodec/pnmdec.c:121
#1  0x00000000007586b8 in avcodec_decode_video2 (avctx=0x1205260,
picture=0x7fffffffd150, got_picture_ptr=0x7fffffffd43c, avpkt=0x1205a00) at
libavcodec/utils.c:637
#2  0x00000000004d7a50 in try_decode_frame (ic=0x1202510) at
libavformat/utils.c:2080
#3  av_find_stream_info (ic=0x1202510) at libavformat/utils.c:2361
#4  0x000000000043175b in opt_input_file (filename=0x7fffffffdafe
"../fuzzed.pgm") at ffmpeg.c:3214
#5  0x000000000043b91c in parse_options (argc=4, argv=0x7fffffffd758,
options=<value optimized out>, parse_arg_function=0x438330 <opt_output_file>) at
cmdutils.c:208
#6  0x0000000000437922 in main (argc=4, argv=0x7fffffffd758) at ffmpeg.c:4345
(gdb) disass $pc-32 $pc+32
A syntax error in expression, near `$pc+32'.
(gdb) info all-registers
rax            0x7f80   32640
rbx            0x12058a0        18897056
rcx            0x1205260        18895456
rdx            0x0      0
rsi            0x7ffff7fd401f   140737353957407
rdi            0x0      0
rbp            0x180    0x180
rsp            0x7fffffffd050   0x7fffffffd050
r8             0x160    352
r9             0x160    352
r10            0x160    352
r11            0x7ffff6d57b33   140737334573875
r12            0x7ffff7f85010   140737353633808
r13            0x7ffff7f85170   140737353634160
r14            0x0      0
r15            0x1      1
rip            0x6c61b3 0x6c61b3 <pnm_decode_frame+1155>
eflags         0x10246  [ PF ZF IF RF ]
cs             0x33     51
ss             0x2b     43
ds             0x0      0
es             0x0      0
fs             0x0      0
gs             0x0      0
st0            0        (raw 0x00000000000000000000)
st1            0        (raw 0x00000000000000000000)
st2            0        (raw 0x00000000000000000000)
st3            0        (raw 0x00000000000000000000)
st4            0        (raw 0x00000000000000000000)
st5            0        (raw 0x00000000000000000000)
st6            0        (raw 0x00000000000000000000)
st7            0        (raw 0x00000000000000000000)
fctrl          0x37f    895
fstat          0x0      0
ftag           0xffff   65535
fiseg          0x0      0
fioff          0x0      0
foseg          0x0      0
fooff          0x0      0
fop            0x0      0
xmm0           {v4_float = {0x0, 0x0, 0x0, 0x0}, v2_double = {0x0, 0x0},
v16_int8 = {0x80 <repeats 16 times>}, v8_int16 = {0x8080, 0x8080, 0x8080,
0x8080, 0x8080,
    0x8080, 0x8080, 0x8080}, v4_int32 = {0x80808080, 0x80808080, 0x80808080,
0x80808080}, v2_int64 = {0x8080808080808080, 0x8080808080808080},
  uint128 = 0x80808080808080808080808080808080}
---Type <return> to continue, or q <return> to quit---
xmm1           {v4_float = {0x0, 0x0, 0x0, 0x0}, v2_double = {0x0, 0x0},
v16_int8 = {0x0 <repeats 16 times>}, v8_int16 = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0},
  v4_int32 = {0x0, 0x0, 0x0, 0x0}, v2_int64 = {0x0, 0x0}, uint128 =
0x00000000000000000000000000000000}
xmm2           {v4_float = {0x0, 0x0, 0x0, 0x0}, v2_double = {0x0,
0x8000000000000000}, v16_int8 = {0x0 <repeats 13 times>, 0xff, 0xff, 0xff},
v8_int16 = {0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0xff00, 0xffff}, v4_int32 = {0x0, 0x0, 0x0, 0xffffff00},
v2_int64 = {0x0, 0xffffff0000000000}, uint128 = 
0xffffff00000000000000000000000000}
xmm3           {v4_float = {0x0, 0x0, 0x0, 0x0}, v2_double =
{0x8000000000000000, 0x8000000000000000}, v16_int8 = {0x0, 0xff <repeats 15
times>}, v8_int16 = {0xff00,
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff}, v4_int32 =
{0xffffff00, 0xffffffff, 0xffffffff, 0xffffffff}, v2_int64 = 
{0xffffffffffffff00,
    0xffffffffffffffff}, uint128 = 0xffffffffffffffffffffffffffffff00}
xmm4           {v4_float = {0x0, 0x0, 0x0, 0x0}, v2_double = {0x0,
0x8000000000000000}, v16_int8 = {0x73, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x54,
0x72, 0x69, 0x65,
    0x64, 0x20, 0x74, 0x6f}, v8_int16 = {0x73, 0x0, 0x0, 0x0, 0x7254, 0x6569,
0x2064, 0x6f74}, v4_int32 = {0x73, 0x0, 0x65697254, 0x6f742064}, v2_int64 = 
{0x73,
    0x6f74206465697254}, uint128 = 0x6f742064656972540000000000000073}
xmm5           {v4_float = {0x0, 0x1, 0x0, 0x0}, v2_double = {0x0, 0x0},
v16_int8 = {0x0, 0x0, 0x0, 0xe0, 0x95, 0x9c, 0xe7, 0x3f, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0, 0x0,
    0x0}, v8_int16 = {0x0, 0xe000, 0x9c95, 0x3fe7, 0x0, 0x0, 0x0, 0x0}, v4_int32
= {0xe0000000, 0x3fe79c95, 0x0, 0x0}, v2_int64 = {0x3fe79c95e0000000, 0x0},
  uint128 = 0x00000000000000003fe79c95e0000000}
xmm6           {v4_float = {0x0, 0x1, 0x0, 0x0}, v2_double = {0x1, 0x0},
v16_int8 = {0x6d, 0x7d, 0xbf, 0xbb, 0x27, 0xaf, 0xf5, 0x3f, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0,
    0x0, 0x0}, v8_int16 = {0x7d6d, 0xbbbf, 0xaf27, 0x3ff5, 0x0, 0x0, 0x0, 0x0},
v4_int32 = {0xbbbf7d6d, 0x3ff5af27, 0x0, 0x0}, v2_int64 = {0x3ff5af27bbbf7d6d, 
0x0},
  uint128 = 0x00000000000000003ff5af27bbbf7d6d}
xmm7           {v4_float = {0x0, 0x0, 0x0, 0x0}, v2_double = {0x0, 0x0},
v16_int8 = {0x0, 0x0, 0x0, 0x0, 0x68, 0xc8, 0xbc, 0x3b, 0x0, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0,
    0x0}, v8_int16 = {0x0, 0x0, 0xc868, 0x3bbc, 0x0, 0x0, 0x0, 0x0}, v4_int32 =
{0x0, 0x3bbcc868, 0x0, 0x0}, v2_int64 = {0x3bbcc86800000000, 0x0},
  uint128 = 0x00000000000000003bbcc86800000000}
xmm8           {v4_float = {0x0, 0xfffffffd, 0x0, 0x0}, v2_double =
{0xffffffffffffffd2, 0x0}, v16_int8 = {0xe0, 0xe6, 0x35, 0x67, 0x9e, 0x6, 0x47,
0xc0, 0x0, 0x0,
    0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, v8_int16 = {0xe6e0, 0x6735, 0x69e, 0xc047,
0x0, 0x0, 0x0, 0x0}, v4_int32 = {0x6735e6e0, 0xc047069e, 0x0, 0x0}, v2_int64 = {
    0xc047069e6735e6e0, 0x0}, uint128 = 0x0000000000000000c047069e6735e6e0}
xmm9           {v4_float = {0x0, 0x1, 0x0, 0x0}, v2_double = {0x1, 0x0},
v16_int8 = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xf0, 0x3f, 0x0, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0,
    0x0}, v8_int16 = {0x0, 0x0, 0x0, 0x3ff0, 0x0, 0x0, 0x0, 0x0}, v4_int32 =
{0x0, 0x3ff00000, 0x0, 0x0}, v2_int64 = {0x3ff0000000000000, 0x0},
  uint128 = 0x00000000000000003ff0000000000000}
xmm10          {v4_float = {0x0, 0x0, 0x0, 0x0}, v2_double = {0x0, 0x0},
v16_int8 = {0x0, 0x0, 0x46, 0x84, 0x24, 0x59, 0xd6, 0x3e, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0, 0x0,
    0x0}, v8_int16 = {0x0, 0x8446, 0x5924, 0x3ed6, 0x0, 0x0, 0x0, 0x0}, v4_int32
= {0x84460000, 0x3ed65924, 0x0, 0x0}, v2_int64 = {0x3ed6592484460000, 0x0},
  uint128 = 0x00000000000000003ed6592484460000}
xmm11          {v4_float = {0x9689a800, 0x0, 0x0, 0x0}, v2_double = {0x0, 0x0},
v16_int8 = {0x6a, 0xa2, 0x65, 0x50, 0xf2, 0xea, 0x8f, 0xbd, 0x0, 0x0, 0x0, 0x0, 
0x0,
    0x0, 0x0, 0x0}, v8_int16 = {0xa26a, 0x5065, 0xeaf2, 0xbd8f, 0x0, 0x0, 0x0,
0x0}, v4_int32 = {0x5065a26a, 0xbd8feaf2, 0x0, 0x0}, v2_int64 = 
{0xbd8feaf25065a26a,
    0x0}, uint128 = 0x0000000000000000bd8feaf25065a26a}
xmm12          {v4_float = {0x0, 0x0, 0x0, 0x0}, v2_double = {0x0, 0x0},
v16_int8 = {0x29, 0xf2, 0x88, 0x6c, 0xa6, 0x49, 0xde, 0x3e, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0,
    0x0, 0x0}, v8_int16 = {0xf229, 0x6c88, 0x49a6, 0x3ede, 0x0, 0x0, 0x0, 0x0},
v4_int32 = {0x6c88f229, 0x3ede49a6, 0x0, 0x0}, v2_int64 = {0x3ede49a66c88f229, 
0x0},
  uint128 = 0x00000000000000003ede49a66c88f229}
xmm13          {v4_float = {0x0, 0x0, 0x0, 0x0}, v2_double = {0x0, 0x0},
v16_int8 = {0xb3, 0x12, 0x58, 0x17, 0x64, 0x46, 0xe6, 0x3b, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0,
    0x0, 0x0}, v8_int16 = {0x12b3, 0x1758, 0x4664, 0x3be6, 0x0, 0x0, 0x0, 0x0},
v4_int32 = {0x175812b3, 0x3be64664, 0x0, 0x0}, v2_int64 = {0x3be64664175812b3, 
0x0},
  uint128 = 0x00000000000000003be64664175812b3}
xmm14          {v4_float = {0x0, 0x3, 0x0, 0x0}, v2_double = {0x2d, 0x0},
v16_int8 = {0xc0, 0x9, 0xf2, 0x16, 0xb5, 0xdf, 0x46, 0x40, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0,
    0x0, 0x0}, v8_int16 = {0x9c0, 0x16f2, 0xdfb5, 0x4046, 0x0, 0x0, 0x0, 0x0},
v4_int32 = {0x16f209c0, 0x4046dfb5, 0x0, 0x0}, v2_int64 = {0x4046dfb516f209c0, 
0x0},
  uint128 = 0x00000000000000004046dfb516f209c0}
xmm15          {v4_float = {0x0, 0x0, 0x0, 0x0}, v2_double = {0x0, 0x0},
v16_int8 = {0x0 <repeats 16 times>}, v8_int16 = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0},
  v4_int32 = {0x0, 0x0, 0x0, 0x0}, v2_int64 = {0x0, 0x0}, uint128 =
0x00000000000000000000000000000000}
mxcsr          0x1fa0   [ PE IM DM ZM OM UM PM ]

----------
files: pgm_check.diff
messages: 13321
priority: normal
status: open
substatus: open
title: ffmpeg crashes on pgm files with invalid maxval
type: bug

________________________________________________
FFmpeg issue tracker <[email protected]>
<https://roundup.ffmpeg.org/issue2518>
________________________________________________

Attachment: pgm_check.diff
Description: Binary data

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