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Code Issues Releases 1 Activity

[huf] Fix OSS-Fuzz assert

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PR #2784 introduced a bug in the decompressor that caused some valid
inputs to fail to decompress. The bitstream isn't reloaded after the 4X*
loop if the number of elements remaining is small enough, causing us to
read more bits than are available in the bitcontainer.

This was caught by the MSAN fuzzer in OSS-Fuzz because the assembly
implementation isn't used in the MSAN build.

Credit to OSS-Fuzz.
This commit is contained in:
Nick Terrell 2021-09-27 13:56:07 -07:00
parent 2ed14c2476
commit a07ddb47f7
1 changed files with 4 additions and 0 deletions
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4
lib/decompress/huf_decompress.c
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@ -531,6 +531,8 @@ HUF_decodeStreamX1(BYTE* p, BIT_DStream_t* const bitDPtr, BYTE* const pEnd, cons
HUF_DECODE_SYMBOLX1_2(p, bitDPtr);
HUF_DECODE_SYMBOLX1_0(p, bitDPtr);
}
} else {
BIT_reloadDStream(bitDPtr);
}
/* [0-3] symbols remaining */
@ -1218,6 +1220,8 @@ HUF_decodeStreamX2(BYTE* p, BIT_DStream_t* bitDPtr, BYTE* const pEnd,
HUF_DECODE_SYMBOLX2_0(p, bitDPtr);
}
}
} else {
BIT_reloadDStream(bitDPtr);
}
/* closer to end : up to 2 symbols at a time */