diff options
author | Pauli <paul.dale@oracle.com> | 2018-08-22 10:04:27 +1000 |
---|---|---|
committer | Pauli <paul.dale@oracle.com> | 2018-08-23 11:12:44 +1000 |
commit | 837017b4748d587912d9d218894644d6ca86721f (patch) | |
tree | afca3cea34ec1205407a443f59c3980d963e36da /crypto | |
parent | 8255fd0f4f86fa4202962d4b27185c0d96f21d75 (diff) |
Zero memory in CRYPTO_secure_malloc.
This commit destroys the free list pointers which would otherwise be
present in the returned memory blocks. This in turn helps prevent
information leakage from the secure memory area.
Note: CRYPTO_secure_malloc is not guaranteed to return zeroed memory:
before the secure memory system is initialised or if it isn't implemented.
[manual merge of #7011]
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/7026)
Diffstat (limited to 'crypto')
-rw-r--r-- | crypto/mem_sec.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/crypto/mem_sec.c b/crypto/mem_sec.c index 25cdb47d56..1ccf68cc93 100644 --- a/crypto/mem_sec.c +++ b/crypto/mem_sec.c @@ -134,11 +134,12 @@ void *CRYPTO_secure_malloc(size_t num, const char *file, int line) void *CRYPTO_secure_zalloc(size_t num, const char *file, int line) { - void *ret = CRYPTO_secure_malloc(num, file, line); - - if (ret != NULL) - memset(ret, 0, num); - return ret; +#ifdef IMPLEMENTED + if (secure_mem_initialized) + /* CRYPTO_secure_malloc() zeroes allocations when it is implemented */ + return CRYPTO_secure_malloc(num, file, line); +#endif + return CRYPTO_zalloc(num, file, line); } void CRYPTO_secure_free(void *ptr, const char *file, int line) @@ -574,6 +575,9 @@ static char *sh_malloc(size_t size) OPENSSL_assert(WITHIN_ARENA(chunk)); + /* zero the free list header as a precaution against information leakage */ + memset(chunk, 0, sizeof(SH_LIST)); + return chunk; } @@ -606,6 +610,8 @@ static void sh_free(char *ptr) list--; + /* Zero the higher addressed block's free list pointers */ + memset(ptr > buddy ? ptr : buddy, 0, sizeof(SH_LIST)); if (ptr > buddy) ptr = buddy; |