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Fix bounds overflow in PCX decoding #4506

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Merged
merged 3 commits into from
Apr 1, 2020
Merged

Fix bounds overflow in PCX decoding #4506

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124f4bb
Tests for PCX OOB Access
wiredfool Mar 9, 2020
6a83e43
Fix OOB Access on PcxDecode.c
wiredfool Mar 9, 2020
ada137e
Fix Flake8
hugovk Apr 1, 2020
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Binary file added Tests/images/01r_00.pcx
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4 changes: 4 additions & 0 deletions Tests/test_image.py
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Original file line number Diff line number Diff line change
Expand Up @@ -638,13 +638,17 @@ def test_pillow_version(self, test_module):
assert test_module.PILLOW_VERSION > "7.0.0"

def test_overrun(self):
""" For overrun completeness, test as:
valgrind pytest -qq Tests/test_image.py::TestImage::test_overrun | grep decode.c
"""
for file in [
"fli_overrun.bin",
"sgi_overrun.bin",
"sgi_overrun_expandrow.bin",
"sgi_overrun_expandrow2.bin",
"pcx_overrun.bin",
"pcx_overrun2.bin",
"01r_00.pcx",
]:
with Image.open(os.path.join("Tests/images", file)) as im:
try:
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5 changes: 1 addition & 4 deletions src/libImaging/PcxDecode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -22,10 +22,7 @@ ImagingPcxDecode(Imaging im, ImagingCodecState state, UINT8* buf, Py_ssize_t byt
UINT8 n;
UINT8* ptr;

if (strcmp(im->mode, "1") == 0 && state->xsize > state->bytes * 8) {
state->errcode = IMAGING_CODEC_OVERRUN;
return -1;
} else if (strcmp(im->mode, "P") == 0 && state->xsize > state->bytes) {
if ((state->xsize * state->bits + 7) / 8 > state->bytes) {
state->errcode = IMAGING_CODEC_OVERRUN;
return -1;
}
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