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add size limit to buffer

This commit is contained in:
Robert Obryk 2024-09-17 16:50:39 +02:00
parent 39bcecf455
commit f1bdfaa803
1 changed files with 23 additions and 9 deletions
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32
python/_brotli.c
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@ -23,6 +23,7 @@ typedef struct {
PyObject *list; PyObject *list;
/* Number of whole allocated size. */ /* Number of whole allocated size. */
Py_ssize_t allocated; Py_ssize_t allocated;
Py_ssize_t size_limit;
} BlocksOutputBuffer; } BlocksOutputBuffer;
static const char unable_allocate_msg[] = "Unable to allocate output buffer."; static const char unable_allocate_msg[] = "Unable to allocate output buffer.";
@ -69,11 +70,17 @@ static const Py_ssize_t BUFFER_BLOCK_SIZE[] =
Return -1 on failure Return -1 on failure
*/ */
static inline int static inline int
BlocksOutputBuffer_InitAndGrow(BlocksOutputBuffer *buffer, BlocksOutputBuffer_InitAndGrow(BlocksOutputBuffer *buffer, Py_ssize_t size_limit,
size_t *avail_out, uint8_t **next_out) size_t *avail_out, uint8_t **next_out)
{ {
PyObject *b; PyObject *b;
const Py_ssize_t block_size = BUFFER_BLOCK_SIZE[0]; Py_ssize_t block_size = BUFFER_BLOCK_SIZE[0];
assert(size_limit > 0);
if (size_limit < block_size) {
block_size = size_limit;
}
// Ensure .list was set to NULL, for BlocksOutputBuffer_OnError(). // Ensure .list was set to NULL, for BlocksOutputBuffer_OnError().
assert(buffer->list == NULL); assert(buffer->list == NULL);
@ -94,6 +101,7 @@ BlocksOutputBuffer_InitAndGrow(BlocksOutputBuffer *buffer,
// Set variables // Set variables
buffer->allocated = block_size; buffer->allocated = block_size;
buffer->size_limit = size_limit;
*avail_out = (size_t) block_size; *avail_out = (size_t) block_size;
*next_out = (uint8_t*) PyBytes_AS_STRING(b); *next_out = (uint8_t*) PyBytes_AS_STRING(b);
@ -122,10 +130,16 @@ BlocksOutputBuffer_Grow(BlocksOutputBuffer *buffer,
block_size = BUFFER_BLOCK_SIZE[Py_ARRAY_LENGTH(BUFFER_BLOCK_SIZE) - 1]; block_size = BUFFER_BLOCK_SIZE[Py_ARRAY_LENGTH(BUFFER_BLOCK_SIZE) - 1];
} }
// Check buffer->allocated overflow if (block_size > buffer->size_limit - buffer->allocated) {
if (block_size > PY_SSIZE_T_MAX - buffer->allocated) { block_size = buffer->size_limit - buffer->allocated;
PyErr_SetString(PyExc_MemoryError, unable_allocate_msg); }
return -1;
if (block_size == 0) {
// We are at the size_limit (either the provided one, in which case we
// shouldn't have been called, or the implicit PY_SSIZE_T_MAX one, in
// which case we wouldn't be able to concatenate the blocks at the end).
PyErr_SetString(PyExc_MemoryError, "too long");
return -1;
} }
// Create the block // Create the block
@ -291,7 +305,7 @@ static PyObject* compress_stream(BrotliEncoderState* enc, BrotliEncoderOperation
BlocksOutputBuffer buffer = {.list=NULL}; BlocksOutputBuffer buffer = {.list=NULL};
PyObject *ret; PyObject *ret;
if (BlocksOutputBuffer_InitAndGrow(&buffer, &available_out, &next_out) < 0) { if (BlocksOutputBuffer_InitAndGrow(&buffer, PY_SSIZE_T_MAX, &available_out, &next_out) < 0) {
goto error; goto error;
} }
@ -604,7 +618,7 @@ static PyObject* decompress_stream(BrotliDecoderState* dec,
BlocksOutputBuffer buffer = {.list=NULL}; BlocksOutputBuffer buffer = {.list=NULL};
PyObject *ret; PyObject *ret;
if (BlocksOutputBuffer_InitAndGrow(&buffer, &available_out, &next_out) < 0) { if (BlocksOutputBuffer_InitAndGrow(&buffer, PY_SSIZE_T_MAX, &available_out, &next_out) < 0) {
goto error; goto error;
} }
@ -877,7 +891,7 @@ static PyObject* brotli_decompress(PyObject *self, PyObject *args, PyObject *key
next_in = (uint8_t*) input.buf; next_in = (uint8_t*) input.buf;
available_in = input.len; available_in = input.len;
if (BlocksOutputBuffer_InitAndGrow(&buffer, &available_out, &next_out) < 0) { if (BlocksOutputBuffer_InitAndGrow(&buffer, PY_SSIZE_T_MAX, &available_out, &next_out) < 0) {
goto error; goto error;
} }