diff options
Diffstat (limited to 'epan/emem.c')
| -rw-r--r-- | epan/emem.c | 111 |
1 files changed, 92 insertions, 19 deletions
diff --git a/epan/emem.c b/epan/emem.c index ecd178213e..f02dbaab8c 100644 --- a/epan/emem.c +++ b/epan/emem.c @@ -41,6 +41,7 @@ #endif #ifdef _WIN32 +#include <windows.h> /* VirtualAlloc, VirtualProtect */ #include <process.h> /* getpid */ #endif @@ -49,6 +50,13 @@ #include "emem.h" #include <wiretap/file_util.h> +/* Add guard pages at each end of our allocated memory */ +#if defined(HAVE_SYSCONF) && defined(HAVE_MMAP) && defined(HAVE_MPROTECT) +#include <sys/types.h> +#include <sys/mman.h> +#define USE_GUARD_PAGES 1 +#endif + /* When required, allocate more memory from the OS in this size chunks */ #define EMEM_PACKET_CHUNK_SIZE 10485760 @@ -73,7 +81,9 @@ guint8 ep_canary[EMEM_CANARY_DATA_SIZE], se_canary[EMEM_CANARY_DATA_SIZE]; typedef struct _emem_chunk_t { struct _emem_chunk_t *next; + unsigned int amount_free_init; unsigned int amount_free; + unsigned int free_offset_init; unsigned int free_offset; char *buf; #if ! defined(EP_DEBUG_FREE) && ! defined(SE_DEBUG_FREE) @@ -169,18 +179,81 @@ se_init_chunk(void) emem_canary(se_canary); } -#define EMEM_CREATE_CHUNK(FREE_LIST) \ - /* we dont have any free data, so we must allocate a new one */ \ - if(!FREE_LIST){ \ - emem_chunk_t *npc; \ - npc=g_malloc(sizeof(emem_chunk_t)); \ - npc->next=NULL; \ - npc->amount_free=EMEM_PACKET_CHUNK_SIZE; \ - npc->free_offset=0; \ - npc->buf=g_malloc(EMEM_PACKET_CHUNK_SIZE); \ - npc->c_count = 0; \ - FREE_LIST=npc; \ +static void +emem_create_chunk(emem_chunk_t **free_list) { +#if defined (_WIN32) + SYSTEM_INFO sysinfo; + int pagesize; + BOOL ret; + char *buf_end, *prot1, *prot2; + DWORD oldprot; +#elif defined(USE_GUARD_PAGES) + int pagesize = sysconf(_SC_PAGESIZE), ret; + char *buf_end, *prot1, *prot2; +#endif + /* we dont have any free data, so we must allocate a new one */ + if(!*free_list){ + emem_chunk_t *npc; + npc = g_malloc(sizeof(emem_chunk_t)); + npc->next = NULL; + npc->c_count = 0; + *free_list = npc; +#if defined (_WIN32) + /* + * MSDN documents VirtualAlloc/VirtualProtect at + * http://msdn.microsoft.com/library/en-us/memory/base/creating_guard_pages.asp + */ + GetSystemInfo(&sysinfo); + pagesize = sysinfo.dwPageSize; + + /* XXX - is MEM_COMMIT|MEM_RESERVE correct? */ + npc->buf = VirtualAlloc(NULL, EMEM_PACKET_CHUNK_SIZE, + MEM_COMMIT|MEM_RESERVE, PAGE_READWRITE); + g_assert(npc->buf != NULL); + buf_end = npc->buf + EMEM_PACKET_CHUNK_SIZE; + + /* Align our guard pages on page-sized boundaries */ + prot1 = (char *) ((((int) npc->buf + pagesize - 1) / pagesize) * pagesize); + prot2 = (char *) ((((int) buf_end - (1 * pagesize)) / pagesize) * pagesize); + + ret = VirtualProtect(prot1, pagesize, PAGE_NOACCESS, &oldprot); + g_assert(ret == TRUE); + ret = VirtualProtect(prot2, pagesize, PAGE_NOACCESS, &oldprot); + g_assert(ret == TRUE); + + npc->amount_free_init = prot2 - prot1 - pagesize; + npc->amount_free = npc->amount_free_init; + npc->free_offset_init = (prot1 - npc->buf) + pagesize; + npc->free_offset = npc->free_offset_init; + +#elif defined(USE_GUARD_PAGES) + npc->buf = mmap(NULL, EMEM_PACKET_CHUNK_SIZE, + PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0); + g_assert(npc->buf != MAP_FAILED); + buf_end = npc->buf + EMEM_PACKET_CHUNK_SIZE; + + /* Align our guard pages on page-sized boundaries */ + prot1 = (char *) ((((int) npc->buf + pagesize - 1) / pagesize) * pagesize); + prot2 = (char *) ((((int) buf_end - (1 * pagesize)) / pagesize) * pagesize); + ret = mprotect(prot1, pagesize, PROT_NONE); + g_assert(ret != -1); + ret = mprotect(prot2, pagesize, PROT_NONE); + g_assert(ret != -1); + + npc->amount_free_init = prot2 - prot1 - pagesize; + npc->amount_free = npc->amount_free_init; + npc->free_offset_init = (prot1 - npc->buf) + pagesize; + npc->free_offset = npc->free_offset_init; + +#else /* Is there a draft in here? */ + npc->amount_free_init = EMEM_PACKET_CHUNK_SIZE; + npc->amount_free = npc->amount_free_init; + npc->free_offset_init = 0; + npc->free_offset = npc->free_offset_init; + npc->buf = g_malloc(EMEM_PACKET_CHUNK_SIZE); +#endif /* USE_GUARD_PAGES */ } +} /* allocate 'size' amount of memory with an allocation lifetime until the * next packet. @@ -201,7 +274,7 @@ ep_alloc(size_t size) /* make sure we dont try to allocate too much (arbitrary limit) */ DISSECTOR_ASSERT(size<(EMEM_PACKET_CHUNK_SIZE>>2)); - EMEM_CREATE_CHUNK(ep_packet_mem.free_list); + emem_create_chunk(&ep_packet_mem.free_list); /* oops, we need to allocate more memory to serve this request * than we have free. move this node to the used list and try again @@ -214,7 +287,7 @@ ep_alloc(size_t size) ep_packet_mem.used_list=npc; } - EMEM_CREATE_CHUNK(ep_packet_mem.free_list); + emem_create_chunk(&ep_packet_mem.free_list); free_list = ep_packet_mem.free_list; @@ -262,7 +335,7 @@ se_alloc(size_t size) /* make sure we dont try to allocate too much (arbitrary limit) */ DISSECTOR_ASSERT(size<(EMEM_PACKET_CHUNK_SIZE>>2)); - EMEM_CREATE_CHUNK(se_packet_mem.free_list); + emem_create_chunk(&se_packet_mem.free_list); /* oops, we need to allocate more memory to serve this request * than we have free. move this node to the used list and try again @@ -275,7 +348,7 @@ se_alloc(size_t size) se_packet_mem.used_list=npc; } - EMEM_CREATE_CHUNK(se_packet_mem.free_list); + emem_create_chunk(&se_packet_mem.free_list); free_list = se_packet_mem.free_list; @@ -530,8 +603,8 @@ ep_free_all(void) g_error("Per-packet memory corrupted."); } npc->c_count = 0; - npc->amount_free=EMEM_PACKET_CHUNK_SIZE; - npc->free_offset=0; + npc->amount_free = npc->amount_free_init; + npc->free_offset = npc->free_offset_init; npc = npc->next; #else /* EP_DEBUG_FREE */ emem_chunk_t *next = npc->next; @@ -571,8 +644,8 @@ se_free_all(void) g_error("Per-session memory corrupted."); } npc->c_count = 0; - npc->amount_free=EMEM_PACKET_CHUNK_SIZE; - npc->free_offset=0; + npc->amount_free = npc->amount_free_init; + npc->free_offset = npc->free_offset_init; npc = npc->next; #else /* SE_DEBUG_FREE */ emem_chunk_t *next = npc->next; |