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Set OPENSSL_NO_BUF_FREELISTS

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The memory freelist maintained by OpenSSL claims to be a performance
optimization for platforms that have a slow malloc/free
implementation. This should not be the case on modern
linux/glibc. Remove the freelist as it poses a potential security
hazard of buffer-reuse that is of "initialized" memory that will not
be caught be tools such as valgrind.

Change-Id: I3cfa6a05f9bdfbbba7820060bae5a673dee43014
Reviewed-on: https://boringssl-review.googlesource.com/1385
Reviewed-by: Adam Langley <agl@google.com>
This commit is contained in:
Alex Chernyakhovsky 2014-08-03 15:48:35 -04:00 committed by Adam Langley
parent 75d1589f60
commit 983f6bdb58
5 changed files with 1 additions and 127 deletions
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1
include/openssl/opensslfeatures.h
View File

@ -20,6 +20,7 @@
#define OPENSSL_NO_BF
#define OPENSSL_NO_BUF_FREELISTS
#define OPENSSL_NO_CAMELLIA
#define OPENSSL_NO_CAST
#define OPENSSL_NO_CMS

6
include/openssl/ssl.h
View File

@ -1010,12 +1010,6 @@ struct ssl_ctx_st
unsigned int (*psk_server_callback)(SSL *ssl, const char *identity,
unsigned char *psk, unsigned int max_psk_len);
#ifndef OPENSSL_NO_BUF_FREELISTS
#define SSL_MAX_BUF_FREELIST_LEN_DEFAULT 32
unsigned int freelist_max_len;
struct ssl3_buf_freelist_st *wbuf_freelist;
struct ssl3_buf_freelist_st *rbuf_freelist;
#endif
/* retain_only_sha256_of_client_certs is true if we should compute the
* SHA256 hash of the peer's certifiate and then discard it to save

71
ssl/s3_both.c
View File

@ -591,79 +591,8 @@ int ssl_verify_alarm_type(long type)
return(al);
}
#ifndef OPENSSL_NO_BUF_FREELISTS
/* On some platforms, malloc() performance is bad enough that you can't just
* free() and malloc() buffers all the time, so we need to use freelists from
* unused buffers. Currently, each freelist holds memory chunks of only a
* given size (list->chunklen); other sized chunks are freed and malloced.
* This doesn't help much if you're using many different SSL option settings
* with a given context. (The options affecting buffer size are
* max_send_fragment, read buffer vs write buffer,
* SSL_OP_MICROSOFT_BIG_WRITE_BUFFER, SSL_OP_NO_COMPRESSION, and
* SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS.) Using a separate freelist for every
* possible size is not an option, since max_send_fragment can take on many
* different values.
*
* If you are on a platform with a slow malloc(), and you're using SSL
* connections with many different settings for these options, and you need to
* use the SSL_MOD_RELEASE_BUFFERS feature, you have a few options:
* - Link against a faster malloc implementation.
* - Use a separate SSL_CTX for each option set.
* - Improve this code.
*/
static void *
freelist_extract(SSL_CTX *ctx, int for_read, int sz)
{
SSL3_BUF_FREELIST *list;
SSL3_BUF_FREELIST_ENTRY *ent = NULL;
void *result = NULL;
CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
list = for_read ? ctx->rbuf_freelist : ctx->wbuf_freelist;
if (list != NULL && sz == (int)list->chunklen)
ent = list->head;
if (ent != NULL)
{
list->head = ent->next;
result = ent;
if (--list->len == 0)
list->chunklen = 0;
}
CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
if (!result)
result = OPENSSL_malloc(sz);
return result;
}
static void
freelist_insert(SSL_CTX *ctx, int for_read, size_t sz, void *mem)
{
SSL3_BUF_FREELIST *list;
SSL3_BUF_FREELIST_ENTRY *ent;
CRYPTO_w_lock(CRYPTO_LOCK_SSL_CTX);
list = for_read ? ctx->rbuf_freelist : ctx->wbuf_freelist;
if (list != NULL &&
(sz == list->chunklen || list->chunklen == 0) &&
list->len < ctx->freelist_max_len &&
sz >= sizeof(*ent))
{
list->chunklen = sz;
ent = mem;
ent->next = list->head;
list->head = ent;
++list->len;
mem = NULL;
}
CRYPTO_w_unlock(CRYPTO_LOCK_SSL_CTX);
if (mem)
OPENSSL_free(mem);
}
#else
#define freelist_extract(c,fr,sz) OPENSSL_malloc(sz)
#define freelist_insert(c,fr,sz,m) OPENSSL_free(m)
#endif
int ssl3_setup_read_buffer(SSL *s)
{

37
ssl/ssl_lib.c
View File

@ -2011,24 +2011,6 @@ SSL_CTX *SSL_CTX_new(const SSL_METHOD *meth)
ret->psk_identity_hint=NULL;
ret->psk_client_callback=NULL;
ret->psk_server_callback=NULL;
#ifndef OPENSSL_NO_BUF_FREELISTS
ret->freelist_max_len = SSL_MAX_BUF_FREELIST_LEN_DEFAULT;
ret->rbuf_freelist = OPENSSL_malloc(sizeof(SSL3_BUF_FREELIST));
if (!ret->rbuf_freelist)
goto err;
ret->rbuf_freelist->chunklen = 0;
ret->rbuf_freelist->len = 0;
ret->rbuf_freelist->head = NULL;
ret->wbuf_freelist = OPENSSL_malloc(sizeof(SSL3_BUF_FREELIST));
if (!ret->wbuf_freelist)
{
OPENSSL_free(ret->rbuf_freelist);
goto err;
}
ret->wbuf_freelist->chunklen = 0;
ret->wbuf_freelist->len = 0;
ret->wbuf_freelist->head = NULL;
#endif
#ifndef OPENSSL_NO_ENGINE
ret->client_cert_engine = NULL;
#ifdef OPENSSL_SSL_CLIENT_ENGINE_AUTO
@ -2062,19 +2044,6 @@ err2:
return(NULL);
}
#ifndef OPENSSL_NO_BUF_FREELISTS
static void
ssl_buf_freelist_free(SSL3_BUF_FREELIST *list)
{
SSL3_BUF_FREELIST_ENTRY *ent, *next;
for (ent = list->head; ent; ent = next)
{
next = ent->next;
OPENSSL_free(ent);
}
OPENSSL_free(list);
}
#endif
void SSL_CTX_free(SSL_CTX *a)
{
@ -2144,12 +2113,6 @@ void SSL_CTX_free(SSL_CTX *a)
#endif
#endif
#ifndef OPENSSL_NO_BUF_FREELISTS
if (a->wbuf_freelist)
ssl_buf_freelist_free(a->wbuf_freelist);
if (a->rbuf_freelist)
ssl_buf_freelist_free(a->rbuf_freelist);
#endif
# ifndef OPENSSL_NO_EC
if (a->tlsext_ecpointformatlist)
OPENSSL_free(a->tlsext_ecpointformatlist);

13
ssl/ssl_locl.h
View File

@ -690,19 +690,6 @@ struct ssl_aead_ctx_st
char variable_nonce_included_in_record;
};
#ifndef OPENSSL_NO_BUF_FREELISTS
typedef struct ssl3_buf_freelist_st
{
size_t chunklen;
unsigned int len;
struct ssl3_buf_freelist_entry_st *head;
} SSL3_BUF_FREELIST;
typedef struct ssl3_buf_freelist_entry_st
{
struct ssl3_buf_freelist_entry_st *next;
} SSL3_BUF_FREELIST_ENTRY;
#endif
extern SSL3_ENC_METHOD ssl3_undef_enc_method;
extern SSL_CIPHER ssl3_ciphers[];