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[3.9] gh-98517: Fix buffer overflows in _sha3 module (GH-98519) #98526

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Merged
merged 1 commit into from
Oct 28, 2022
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[3.9] gh-98517: Fix buffer overflows in _sha3 module (GH-98519) #98526

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9 changes: 9 additions & 0 deletions Lib/test/test_hashlib.py
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Original file line number Diff line number Diff line change
Expand Up @@ -497,6 +497,15 @@ def test_case_md5_huge(self, size):
def test_case_md5_uintmax(self, size):
self.check('md5', b'A'*size, '28138d306ff1b8281f1a9067e1a1a2b3')

@unittest.skipIf(sys.maxsize < _4G - 1, 'test cannot run on 32-bit systems')
@bigmemtest(size=_4G - 1, memuse=1, dry_run=False)
def test_sha3_update_overflow(self, size):
"""Regression test for gh-98517 CVE-2022-37454."""
h = hashlib.sha3_224()
h.update(b'\x01')
h.update(b'\x01'*0xffff_ffff)
self.assertEqual(h.hexdigest(), '80762e8ce6700f114fec0f621fd97c4b9c00147fa052215294cceeed')

# use the three examples from Federal Information Processing Standards
# Publication 180-1, Secure Hash Standard, 1995 April 17
# http://www.itl.nist.gov/div897/pubs/fip180-1.htm
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1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Security/2022-10-21-13-31-47.gh-issue-98517.SXXGfV.rst
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@@ -0,0 +1 @@
Port XKCP's fix for the buffer overflows in SHA-3 (CVE-2022-37454).
15 changes: 8 additions & 7 deletions Modules/_sha3/kcp/KeccakSponge.inc
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Original file line number Diff line number Diff line change
Expand Up @@ -171,7 +171,7 @@ int SpongeAbsorb(SpongeInstance *instance, const unsigned char *data, size_t dat
i = 0;
curData = data;
while(i < dataByteLen) {
if ((instance->byteIOIndex == 0) && (dataByteLen >= (i + rateInBytes))) {
if ((instance->byteIOIndex == 0) && (dataByteLen-i >= rateInBytes)) {
#ifdef SnP_FastLoop_Absorb
/* processing full blocks first */

Expand Down Expand Up @@ -199,10 +199,10 @@ int SpongeAbsorb(SpongeInstance *instance, const unsigned char *data, size_t dat
}
else {
/* normal lane: using the message queue */

partialBlock = (unsigned int)(dataByteLen - i);
if (partialBlock+instance->byteIOIndex > rateInBytes)
if (dataByteLen-i > rateInBytes-instance->byteIOIndex)
partialBlock = rateInBytes-instance->byteIOIndex;
else
partialBlock = (unsigned int)(dataByteLen - i);
#ifdef KeccakReference
displayBytes(1, "Block to be absorbed (part)", curData, partialBlock);
#endif
Expand Down Expand Up @@ -281,7 +281,7 @@ int SpongeSqueeze(SpongeInstance *instance, unsigned char *data, size_t dataByte
i = 0;
curData = data;
while(i < dataByteLen) {
if ((instance->byteIOIndex == rateInBytes) && (dataByteLen >= (i + rateInBytes))) {
if ((instance->byteIOIndex == rateInBytes) && (dataByteLen-i >= rateInBytes)) {
for(j=dataByteLen-i; j>=rateInBytes; j-=rateInBytes) {
SnP_Permute(instance->state);
SnP_ExtractBytes(instance->state, curData, 0, rateInBytes);
Expand All @@ -299,9 +299,10 @@ int SpongeSqueeze(SpongeInstance *instance, unsigned char *data, size_t dataByte
SnP_Permute(instance->state);
instance->byteIOIndex = 0;
}
partialBlock = (unsigned int)(dataByteLen - i);
if (partialBlock+instance->byteIOIndex > rateInBytes)
if (dataByteLen-i > rateInBytes-instance->byteIOIndex)
partialBlock = rateInBytes-instance->byteIOIndex;
else
partialBlock = (unsigned int)(dataByteLen - i);
i += partialBlock;

SnP_ExtractBytes(instance->state, curData, instance->byteIOIndex, partialBlock);
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