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UBSAN error in gzread.c #783

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nmoinvaz opened this issue Oct 2, 2020 · 1 comment
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UBSAN error in gzread.c #783

nmoinvaz opened this issue Oct 2, 2020 · 1 comment

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@nmoinvaz
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nmoinvaz commented Oct 2, 2020 •
edited 

2: /Users/runner/work/zlib-ng/zlib-ng/gzread.c:398:18: runtime error: unsigned integer overflow: 18446744073709551615 * 18446744073709551615 cannot be represented in type 'unsigned long'
2: SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /Users/runner/work/zlib-ng/zlib-ng/gzread.c:398:18 in

https://github.com/nmoinvaz/zlib-ng/runs/1197163500?check_suite_focus=true see macOS Clang run.
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nmoinvaz commented Oct 2, 2020 •
edited

zlib-ng/gzread.c

Lines 397 to 402 in b55680b

/* compute bytes to read -- error on overflow */
len = nitems * size;
if (size && len / size != nitems) {
gz_error(state, Z_STREAM_ERROR, "request does not fit in a size_t");
return 0;
}

Seems that overflow is expected here.

nmoinvaz added a commit to nmoinvaz/zlib-ng that referenced this issue Oct 31, 2020
@nmoinvaz
Fixed ubsan warning in gzfread due to size_t overflow. zlib-ng#783
e2bebe0 
gzread.c:398:18: runtime error: unsigned integer overflow: 2 * 18446744073709551615 cannot be represented in type 'unsigned long'
    #0 0x10009d31e in zng_gzfread gzread.c:398
    #1 0x100005b1a in test_gzio example.c:213
    #2 0x10001093b in main example.c:1034
    zlib-ng#3 0x7fff71f57cc8 in start+0x0 (libdyld.dylib:x86_64+0x1acc8)
@nmoinvaz nmoinvaz mentioned this issue Oct 31, 2020
Merged
Dead2 pushed a commit that referenced this issue Nov 2, 2020
@nmoinvaz @Dead2
Fixed ubsan warning in gzfread due to size_t overflow. #783
48c0891 
gzread.c:398:18: runtime error: unsigned integer overflow: 2 * 18446744073709551615 cannot be represented in type 'unsigned long'
    #0 0x10009d31e in zng_gzfread gzread.c:398
    #1 0x100005b1a in test_gzio example.c:213
    #2 0x10001093b in main example.c:1034
    #3 0x7fff71f57cc8 in start+0x0 (libdyld.dylib:x86_64+0x1acc8)
@nmoinvaz nmoinvaz closed this as completed Nov 2, 2020
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