From 1b162c9efc7aeee65a41ec8284a6effb1f9d68cd Mon Sep 17 00:00:00 2001
From: Dominik Loidolt <dominik.loidolt@univie.ac.at>
Date: Tue, 16 Jan 2024 11:50:30 +0100
Subject: [PATCH] Fixing: applying non-zero offset to null pointer when reading
a stream with 0 size
---
lib/decompress/read_bitstream.h | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/lib/decompress/read_bitstream.h b/lib/decompress/read_bitstream.h
index 920540e..c65090e 100644
--- a/lib/decompress/read_bitstream.h
+++ b/lib/decompress/read_bitstream.h
@@ -45,6 +45,7 @@
#include <string.h>
#include "../common/byteorder.h"
+#include "../common/compiler.h"
@@ -123,14 +124,18 @@ static __inline uint64_t bit_read_unaligned_64be(const void *ptr)
static __inline size_t bit_init_decoder(struct bit_decoder *dec, const void *buf,
size_t buf_size)
{
+ assert(dec != NULL);
+ assert(buf != NULL);
+
+ dec->cursor = (const uint8_t *)buf;
+
if (buf_size < 1) {
- memset(dec, 0, sizeof(*dec));
dec->bits_consumed = sizeof(dec->bit_container)*8;
+ dec->bit_container = 0;
+ dec->limit_ptr = (const uint8_t *)buf;
return 0;
}
- dec->cursor = (const uint8_t *)buf;
-
if (buf_size >= sizeof(dec->bit_container)) { /* normal case */
dec->bits_consumed = 0;
dec->bit_container = bit_read_unaligned_64be(dec->cursor);
@@ -320,7 +325,7 @@ static __inline int bit_refill(struct bit_decoder *dec)
{
unsigned int const bytes_consumed = dec->bits_consumed >> 3;
- if (dec->bits_consumed > sizeof(dec->bit_container)*8)
+ if (unlikely(dec->bits_consumed > sizeof(dec->bit_container)*8))
return BIT_OVERFLOW;
if (dec->cursor + bytes_consumed < dec->limit_ptr) {
--
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