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fix potential invalid mmap call and uninitialized file size #4559

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fix potential invalid mmap call and uninitialized file size #4559

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5f24f87
fix potential invalid mmap call and uninitialized file size
richardsonnick Dec 23, 2025
7114309
Merge branch 'facebook:dev' into fix-zero-filesize-mmap
richardsonnick Mar 12, 2026
01c8f60
Relocate unitialized file size check and use UTIL_FILESIZE_UNKNOWN
richardsonnick Mar 12, 2026
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6 changes: 6 additions & 0 deletions programs/fileio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1040,6 +1040,7 @@ static size_t FIO_setDictBufferMMap(FIO_Dict_t* dict, const char* fileName, FIO_
EXM_THROW(33, "Couldn't open dictionary %s: %s", fileName, strerror(errno));
}

// filesize could be garbage if UTIL_getFileSizeStat fails
fileSize = UTIL_getFileSizeStat(dictFileStat);
{
size_t const dictSizeMax = prefs->patchFromMode ? prefs->memLimit : DICTSIZE_MAX;
Expand All @@ -1049,6 +1050,11 @@ static size_t FIO_setDictBufferMMap(FIO_Dict_t* dict, const char* fileName, FIO_
}
}

if (fileSize == 0) return 0;
if (fileSize == (unsigned long long)-1) {
EXM_THROW(35, "Could not determine size of dictionary %s", fileName);
}

*bufferPtr = mmap(NULL, (size_t)fileSize, PROT_READ, MAP_PRIVATE, fileHandle, 0);
if (*bufferPtr==NULL) EXM_THROW(34, "%s", strerror(errno));

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