83 lines
2.7 KiB
C
83 lines
2.7 KiB
C
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///////////////////////////////////////////////////////////////////////////////
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//
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/// \file fuzz.c
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/// \brief Fuzz test program for liblzma
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//
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// Author: Lasse Collin
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//
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// This file has been put into the public domain.
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// You can do whatever you want with this file.
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//
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///////////////////////////////////////////////////////////////////////////////
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#include <inttypes.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include "lzma.h"
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// Output buffer for decompressed data. This is write only; nothing cares
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// about the actual data written here.
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static uint8_t outbuf[4096];
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extern int
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LLVMFuzzerTestOneInput(const uint8_t *inbuf, size_t inbuf_size)
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{
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// Some header values can make liblzma allocate a lot of RAM
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// (up to about 4 GiB with liblzma 5.2.x). We set a limit here to
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// prevent extreme allocations when fuzzing.
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const uint64_t memlimit = 300 << 20; // 300 MiB
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// Initialize a .xz decoder using the above memory usage limit.
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// Enable support for concatenated .xz files which is used when
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// decompressing regular .xz files (instead of data embedded inside
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// some other file format). Integrity checks on the uncompressed
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// data are ignored to make fuzzing more effective (incorrect check
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// values won't prevent the decoder from processing more input).
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//
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// The flag LZMA_IGNORE_CHECK doesn't disable verification of header
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// CRC32 values. Those checks are disabled when liblzma is built
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// with the #define FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION.
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lzma_stream strm = LZMA_STREAM_INIT;
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lzma_ret ret = lzma_stream_decoder(&strm, memlimit,
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LZMA_CONCATENATED | LZMA_IGNORE_CHECK);
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if (ret != LZMA_OK) {
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// This should never happen unless the system has
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// no free memory or address space to allow the small
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// allocations that the initialization requires.
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fprintf(stderr, "lzma_stream_decoder() failed (%d)\n", ret);
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abort();
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}
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// Give the whole input buffer at once to liblzma.
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// Output buffer isn't initialized as liblzma only writes to it.
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strm.next_in = inbuf;
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strm.avail_in = inbuf_size;
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strm.next_out = outbuf;
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strm.avail_out = sizeof(outbuf);
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while ((ret = lzma_code(&strm, LZMA_FINISH)) == LZMA_OK) {
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if (strm.avail_out == 0) {
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// outbuf became full. We don't care about the
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// uncompressed data there, so we simply reuse
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// the outbuf and overwrite the old data.
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strm.next_out = outbuf;
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strm.avail_out = sizeof(outbuf);
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}
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}
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// LZMA_PROG_ERROR should never happen as long as the code calling
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// the liblzma functions is correct. Thus LZMA_PROG_ERROR is a sign
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// of a bug in either this function or in liblzma.
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if (ret == LZMA_PROG_ERROR) {
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fprintf(stderr, "lzma_code() returned LZMA_PROG_ERROR\n");
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abort();
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}
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// Free the allocated memory.
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lzma_end(&strm);
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return 0;
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}
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