6652, 12926, 13862, 14132, 14138, 14171, 14498, 15215, 15884, 16469,
16619, 16740, 16857, 17192, 17266, 17344, 17363, 17370, 17371, 17411,
17460, 17475, 17485, 17501, 17506, 17508, 17522, 17555, 17570, 17571,
- 17572, 17573, 17574, 17582, 17583, 17584, 17585, 17589, 17594, 17608,
- 17616, 17625, 17633.
+ 17572, 17573, 17574, 17581, 17582, 17583, 17584, 17585, 17589, 17594,
+ 17608, 17616, 17625, 17633.
* CVE-2104-7817 The wordexp function could ignore the WRDE_NOCMD flag
under certain input conditions resulting in the execution of a shell for
#define MAGICBYTE(p) ((((size_t) p >> 3) ^ ((size_t) p >> 11)) & 0xFF)
-/* Visualize the chunk as being partitioned into blocks of 256 bytes from the
- highest address of the chunk, downwards. The beginning of each block tells
- us the size of the previous block, up to the actual size of the requested
- memory. Our magic byte is right at the end of the requested size, so we
- must reach it with this iteration, otherwise we have witnessed a memory
- corruption. */
+/* Visualize the chunk as being partitioned into blocks of 255 bytes from the
+ highest address of the chunk, downwards. The end of each block tells us
+ the size of that block, up to the actual size of the requested memory.
+ The last block has a length of zero and is followed by the magic byte.
+ Our magic byte is right at the end of the requested size. If we don't
+ reach it with this iteration we have witnessed a memory corruption. */
static size_t
malloc_check_get_size (mchunkptr p)
{
- size_t size;
+ size_t total_sz, size;
unsigned char c;
unsigned char magic = MAGICBYTE (p);
assert (using_malloc_checking == 1);
- for (size = chunksize (p) - 1 + (chunk_is_mmapped (p) ? 0 : SIZE_SZ);
- (c = ((unsigned char *) p)[size]) != magic;
+ /* Validate the length-byte chain. */
+ total_sz = chunksize (p) + (chunk_is_mmapped (p) ? 0 : SIZE_SZ);
+ for (size = total_sz - 1;
+ (c = ((unsigned char *) p)[size]) != 0;
size -= c)
{
- if (c <= 0 || size < (c + 2 * SIZE_SZ))
- {
- malloc_printerr (check_action, "malloc_check_get_size: memory corruption",
- chunk2mem (p));
- return 0;
- }
+ if (size <= c + 2 * SIZE_SZ)
+ break;
+ }
+ if (c != 0 || ((unsigned char *) p)[--size] != magic)
+ {
+ malloc_printerr (check_action, "malloc_check_get_size: memory corruption",
+ chunk2mem (p));
+ return 0;
}
/* chunk2mem size. */
{
mchunkptr p;
unsigned char *m_ptr = ptr;
- size_t i;
+ size_t user_sz, block_sz, i;
if (!ptr)
return ptr;
p = mem2chunk (ptr);
- for (i = chunksize (p) - (chunk_is_mmapped (p) ? 2 * SIZE_SZ + 1 : SIZE_SZ + 1);
- i > sz;
- i -= 0xFF)
+ user_sz = chunksize (p) + (chunk_is_mmapped (p) ? 0 : SIZE_SZ);
+ user_sz -= 2 * SIZE_SZ;
+ for (i = user_sz - 1; i > sz; i -= block_sz)
{
- if (i - sz < 0x100)
- {
- m_ptr[i] = (unsigned char) (i - sz);
- break;
- }
- m_ptr[i] = 0xFF;
+ block_sz = i - (sz + 1);
+ if (block_sz > 0xff)
+ block_sz = 0xff;
+
+ m_ptr[i] = (unsigned char) block_sz;
+
+ if (block_sz == 0)
+ break;
}
m_ptr[sz] = MAGICBYTE (p);
return (void *) m_ptr;
return NULL;
p = mem2chunk (mem);
+ sz = chunksize (p);
+ magic = MAGICBYTE (p);
if (!chunk_is_mmapped (p))
{
/* Must be a chunk in conventional heap memory. */
int contig = contiguous (&main_arena);
- sz = chunksize (p);
if ((contig &&
((char *) p < mp_.sbrk_base ||
((char *) p + sz) >= (mp_.sbrk_base + main_arena.system_mem))) ||
next_chunk (prev_chunk (p)) != p)))
return NULL;
- magic = MAGICBYTE (p);
- for (sz += SIZE_SZ - 1; (c = ((unsigned char *) p)[sz]) != magic; sz -= c)
+ for (sz += SIZE_SZ - 1; (c = ((unsigned char *) p)[sz]) != 0; sz -= c)
{
- if (c <= 0 || sz < (c + 2 * SIZE_SZ))
- return NULL;
+ if (sz <= c + 2 * SIZE_SZ)
+ break;
}
+ if (c != 0 || ((unsigned char *) p)[--sz] != magic)
+ return NULL;
}
else
{
offset < 0x2000) ||
!chunk_is_mmapped (p) || (p->size & PREV_INUSE) ||
((((unsigned long) p - p->prev_size) & page_mask) != 0) ||
- ((sz = chunksize (p)), ((p->prev_size + sz) & page_mask) != 0))
+ ((p->prev_size + sz) & page_mask) != 0)
return NULL;
- magic = MAGICBYTE (p);
- for (sz -= 1; (c = ((unsigned char *) p)[sz]) != magic; sz -= c)
+ for (sz -= 1; (c = ((unsigned char *) p)[sz]) != 0; sz -= c)
{
- if (c <= 0 || sz < (c + 2 * SIZE_SZ))
- return NULL;
+ if (sz <= c + 2 * SIZE_SZ)
+ break;
}
+ if (c != 0 || ((unsigned char *) p)[--sz] != magic)
+ return NULL;
}
((unsigned char *) p)[sz] ^= 0xFF;
if (magic_p)