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Add a fuzzer for ReadHuffmanCodes

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Change-Id: If8c30aaa87c34007ae455a03daa7b3c0f22fc8c3
This commit is contained in:
Vincent Rabaud
2023-09-12 23:11:37 +02:00
parent 95ea5226c8
commit a35ea50de4
4 changed files with 127 additions and 21 deletions
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64
src/dec/vp8l_dec.c
View File

@ -364,7 +364,7 @@ static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec,
static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
int color_cache_bits, int allow_recursion) {
int i, j;
int i;
VP8LBitReader* const br = &dec->br_;
VP8LMetadata* const hdr = &dec->hdr_;
uint32_t* huffman_image = NULL;
@ -372,10 +372,6 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
HuffmanTables* huffman_tables = &hdr->huffman_tables_;
int num_htree_groups = 1;
int num_htree_groups_max = 1;
const int max_alphabet_size =
kAlphabetSize[0] + ((color_cache_bits > 0) ? 1 << color_cache_bits : 0);
int* code_lengths = NULL;
const int table_size = kTableSize[color_cache_bits];
int* mapping = NULL;
int ok = 0;
@ -432,11 +428,49 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
if (br->eos_) goto Error;
code_lengths = (int*)WebPSafeCalloc((uint64_t)max_alphabet_size,
sizeof(*code_lengths));
htree_groups = VP8LHtreeGroupsNew(num_htree_groups);
if (!ReadHuffmanCodesHelper(color_cache_bits, num_htree_groups,
num_htree_groups_max, mapping, dec,
huffman_tables, &htree_groups)) {
goto Error;
}
ok = 1;
if (htree_groups == NULL || code_lengths == NULL ||
// All OK. Finalize pointers.
hdr->huffman_image_ = huffman_image;
hdr->num_htree_groups_ = num_htree_groups;
hdr->htree_groups_ = htree_groups;
Error:
WebPSafeFree(mapping);
if (!ok) {
WebPSafeFree(huffman_image);
VP8LHuffmanTablesDeallocate(huffman_tables);
VP8LHtreeGroupsFree(htree_groups);
}
return ok;
}
int ReadHuffmanCodesHelper(int color_cache_bits, int num_htree_groups,
int num_htree_groups_max, const int* const mapping,
VP8LDecoder* const dec,
HuffmanTables* const huffman_tables,
HTreeGroup** const htree_groups) {
int i, j, ok = 0;
const int max_alphabet_size =
kAlphabetSize[0] + ((color_cache_bits > 0) ? 1 << color_cache_bits : 0);
const int table_size = kTableSize[color_cache_bits];
int* code_lengths = NULL;
if ((mapping == NULL && num_htree_groups != num_htree_groups_max) ||
num_htree_groups > num_htree_groups_max) {
goto Error;
}
code_lengths =
(int*)WebPSafeCalloc((uint64_t)max_alphabet_size, sizeof(*code_lengths));
*htree_groups = VP8LHtreeGroupsNew(num_htree_groups);
if (*htree_groups == NULL || code_lengths == NULL ||
!VP8LHuffmanTablesAllocate(num_htree_groups * table_size,
huffman_tables)) {
VP8LSetError(dec, VP8_STATUS_OUT_OF_MEMORY);
@ -459,7 +493,7 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
}
} else {
HTreeGroup* const htree_group =
&htree_groups[(mapping == NULL) ? i : mapping[i]];
&(*htree_groups)[(mapping == NULL) ? i : mapping[i]];
HuffmanCode** const htrees = htree_group->htrees;
int size;
int total_size = 0;
@ -511,18 +545,12 @@ static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize,
}
ok = 1;
// All OK. Finalize pointers.
hdr->huffman_image_ = huffman_image;
hdr->num_htree_groups_ = num_htree_groups;
hdr->htree_groups_ = htree_groups;
Error:
WebPSafeFree(code_lengths);
WebPSafeFree(mapping);
if (!ok) {
WebPSafeFree(huffman_image);
VP8LHuffmanTablesDeallocate(huffman_tables);
VP8LHtreeGroupsFree(htree_groups);
VP8LHtreeGroupsFree(*htree_groups);
*htree_groups = NULL;
}
return ok;
}

13
src/dec/vp8li_dec.h
View File

@ -126,6 +126,19 @@ void VP8LClear(VP8LDecoder* const dec);
// Clears and deallocate a lossless decoder instance.
void VP8LDelete(VP8LDecoder* const dec);
// Helper function for reading the different Huffman codes and storing them in
// 'huffman_tables' and 'htree_groups'.
// If mapping is NULL 'num_htree_groups_max' must equal 'num_htree_groups'.
// If it is not NULL, it maps 'num_htree_groups_max' indices to the
// 'num_htree_groups' groups. If 'num_htree_groups_max' > 'num_htree_groups',
// some of those indices map to -1. This is used for non-balanced codes to
// limit memory usage.
int ReadHuffmanCodesHelper(int color_cache_bits, int num_htree_groups,
int num_htree_groups_max, const int* const mapping,
VP8LDecoder* const dec,
HuffmanTables* const huffman_tables,
HTreeGroup** const htree_groups);
//------------------------------------------------------------------------------
#ifdef __cplusplus