diff options
Diffstat (limited to 'src/common/memarea.c')
| -rw-r--r-- | src/common/memarea.c | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/src/common/memarea.c b/src/common/memarea.c index b5ac7ad97a..a6b8c4ee9c 100644 --- a/src/common/memarea.c +++ b/src/common/memarea.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2008-2010, The Tor Project, Inc. */ +/* Copyright (c) 2008-2011, The Tor Project, Inc. */ /* See LICENSE for licensing information */ /** \file memarea.c @@ -30,12 +30,18 @@ #endif #ifdef USE_SENTINELS +/** Magic value that we stick at the end of a memarea so we can make sure + * there are no run-off-the-end bugs. */ #define SENTINEL_VAL 0x90806622u +/** How many bytes per area do we devote to the sentinel? */ #define SENTINEL_LEN sizeof(uint32_t) +/** Given a mem_area_chunk_t with SENTINEL_LEN extra bytes allocated at the + * end, set those bytes. */ #define SET_SENTINEL(chunk) \ STMT_BEGIN \ set_uint32( &(chunk)->u.mem[chunk->mem_size], SENTINEL_VAL ); \ STMT_END +/** Assert that the sentinel on a memarea is set correctly. */ #define CHECK_SENTINEL(chunk) \ STMT_BEGIN \ uint32_t sent_val = get_uint32(&(chunk)->u.mem[chunk->mem_size]); \ @@ -53,7 +59,9 @@ realign_pointer(void *ptr) { uintptr_t x = (uintptr_t)ptr; x = (x+MEMAREA_ALIGN_MASK) & ~MEMAREA_ALIGN_MASK; + /* Reinstate this if bug 930 ever reappears tor_assert(((void*)x) >= ptr); + */ return (void*)x; } @@ -73,8 +81,11 @@ typedef struct memarea_chunk_t { } u; } memarea_chunk_t; +/** How many bytes are needed for overhead before we get to the memory part + * of a chunk? */ #define CHUNK_HEADER_SIZE STRUCT_OFFSET(memarea_chunk_t, u) +/** What's the smallest that we'll allocate a chunk? */ #define CHUNK_SIZE 4096 /** A memarea_t is an allocation region for a set of small memory requests @@ -95,6 +106,7 @@ static memarea_chunk_t *freelist = NULL; static memarea_chunk_t * alloc_chunk(size_t sz, int freelist_ok) { + tor_assert(sz < SIZE_T_CEILING); if (freelist && freelist_ok) { memarea_chunk_t *res = freelist; freelist = res->next_chunk; @@ -211,6 +223,7 @@ memarea_alloc(memarea_t *area, size_t sz) char *result; tor_assert(chunk); CHECK_SENTINEL(chunk); + tor_assert(sz < SIZE_T_CEILING); if (sz == 0) sz = 1; if (chunk->next_mem+sz > chunk->u.mem+chunk->mem_size) { @@ -230,10 +243,10 @@ memarea_alloc(memarea_t *area, size_t sz) } result = chunk->next_mem; chunk->next_mem = chunk->next_mem + sz; - + /* Reinstate these if bug 930 ever comes back tor_assert(chunk->next_mem >= chunk->u.mem); tor_assert(chunk->next_mem <= chunk->u.mem+chunk->mem_size); - + */ chunk->next_mem = realign_pointer(chunk->next_mem); return result; } @@ -270,6 +283,7 @@ memarea_strndup(memarea_t *area, const char *s, size_t n) size_t ln; char *result; const char *cp, *end = s+n; + tor_assert(n < SIZE_T_CEILING); for (cp = s; cp < end && *cp; ++cp) ; /* cp now points to s+n, or to the 0 in the string. */ |