Add OPENSSL_cleanse() to help cleanse memory and avoid certain compiler

and linker optimizations.
PR: 343

diff --git a/CHANGES b/CHANGES
index ac3a1344a90224260559aaa40cab689a4546381d..6e31374fd328cab0df516aea48e132d2384bbadc 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1785,6 +1785,14 @@ des-cbc           3624.96k     5258.21k     5530.91k     5624.30k     5628.26k
 
  Changes between 0.9.6g and 0.9.6h  [xx XXX xxxx]
 
+  *) New function OPENSSL_cleanse(), which is used to cleanse a section of
+     memory from it's contents.  This is done with a counter that will
+     place alternating values in each byte.  This can be used to solve
+     two issues: 1) the removal of calls to memset() by highly optimizing
+     compilers, and 2) cleansing with other values than 0, since those can
+     be read through on certain media, for example a swap space on disk.
+     [Geoff Thorpe]
+
   *) Bugfix: client side session caching did not work with external caching,
      because the session->cipher setting was not restored when reloading
      from the external cache. This problem was masked, when

diff --git a/crypto/Makefile.ssl b/crypto/Makefile.ssl
index f50aa7f08ca6109495fc4eaf64fe2b5c467f4a47..3766e7c4dab03875d4af0262ea10336eb591c16b 100644 (file)
--- a/crypto/Makefile.ssl
+++ b/crypto/Makefile.ssl
@@ -36,8 +36,8 @@ GENERAL=Makefile README crypto-lib.com install.com
 
 LIB= $(TOP)/libcrypto.a
 SHARED_LIB= libcrypto$(SHLIB_EXT)
-LIBSRC=        cryptlib.c mem.c mem_dbg.c cversion.c ex_data.c tmdiff.c cpt_err.c ebcdic.c uid.c o_time.c
-LIBOBJ= cryptlib.o mem.o mem_dbg.o cversion.o ex_data.o tmdiff.o cpt_err.o ebcdic.o uid.o o_time.o
+LIBSRC=        cryptlib.c mem.c mem_clr.c mem_dbg.c cversion.c ex_data.c tmdiff.c cpt_err.c ebcdic.c uid.c o_time.c
+LIBOBJ= cryptlib.o mem.o mem_clr.o mem_dbg.o cversion.o ex_data.o tmdiff.o cpt_err.o ebcdic.o uid.o o_time.o
 
 SRC= $(LIBSRC)
 
@@ -193,6 +193,10 @@ mem.o: ../include/openssl/err.h ../include/openssl/lhash.h
 mem.o: ../include/openssl/opensslconf.h ../include/openssl/opensslv.h
 mem.o: ../include/openssl/safestack.h ../include/openssl/stack.h
 mem.o: ../include/openssl/symhacks.h cryptlib.h mem.c
+mem_clr.o: ../include/openssl/crypto.h ../include/openssl/e_os2.h
+mem_clr.o: ../include/openssl/opensslconf.h ../include/openssl/opensslv.h
+mem_clr.o: ../include/openssl/safestack.h ../include/openssl/stack.h
+mem_clr.o: ../include/openssl/symhacks.h mem_clr.c
 mem_dbg.o: ../e_os.h ../include/openssl/bio.h ../include/openssl/buffer.h
 mem_dbg.o: ../include/openssl/crypto.h ../include/openssl/e_os2.h
 mem_dbg.o: ../include/openssl/err.h ../include/openssl/lhash.h

diff --git a/crypto/crypto-lib.com b/crypto/crypto-lib.com
index 2addf4e793c47cf028376bce95cc1b457aed30cd..39e78c69e50829ad9d78badb2bb283fbac40b61d 100644 (file)
--- a/crypto/crypto-lib.com
+++ b/crypto/crypto-lib.com
@@ -158,7 +158,7 @@ $!
 $ APPS_DES = "DES/DES,CBC3_ENC"
 $ APPS_PKCS7 = "ENC/ENC;DEC/DEC;SIGN/SIGN;VERIFY/VERIFY,EXAMPLE"
 $
-$ LIB_ = "cryptlib,mem,mem_dbg,cversion,ex_data,tmdiff,cpt_err,ebcdic,uid,o_time"
+$ LIB_ = "cryptlib,mem,mem_clr,mem_dbg,cversion,ex_data,tmdiff,cpt_err,ebcdic,uid,o_time"
 $ LIB_MD2 = "md2_dgst,md2_one"
 $ LIB_MD4 = "md4_dgst,md4_one"
 $ LIB_MD5 = "md5_dgst,md5_one"

diff --git a/crypto/crypto.h b/crypto/crypto.h
index 4b9ece9762d7fc238b170a7ada6c418c74c5b5ef..69441cfd7f3aea67a9cc7db872226caff4f8b76e 100644 (file)
--- a/crypto/crypto.h
+++ b/crypto/crypto.h
@@ -390,6 +390,8 @@ void *CRYPTO_realloc_clean(void *addr,int old_num,int num,const char *file,
                           int line);
 void *CRYPTO_remalloc(void *addr,int num, const char *file, int line);
 
+void OPENSSL_cleanse(void *ptr, size_t len);
+
 void CRYPTO_set_mem_debug_options(long bits);
 long CRYPTO_get_mem_debug_options(void);
 

diff --git a/crypto/mem.c b/crypto/mem.c
index 03d2569bced7c0c0980551e02802f66deb7c4d54..46a00697ce22147579763fa5b9bb55bb1cb9980b 100644 (file)
--- a/crypto/mem.c
+++ b/crypto/mem.c
@@ -250,6 +250,7 @@ void CRYPTO_get_mem_debug_functions(void (**m)(void *,int,const char *,int,int),
 void *CRYPTO_malloc_locked(int num, const char *file, int line)
        {
        void *ret = NULL;
+       extern unsigned char cleanse_ctr;
 
        allow_customize = 0;
        if (malloc_debug_func != NULL)
@@ -264,6 +265,12 @@ void *CRYPTO_malloc_locked(int num, const char *file, int line)
        if (malloc_debug_func != NULL)
                malloc_debug_func(ret, num, file, line, 1);
 
+        /* Create a dependency on the value of 'cleanse_ctr' so our memory
+         * sanitisation function can't be optimised out. NB: We only do
+         * this for >2Kb so the overhead doesn't bother us. */
+        if(ret && (num > 2048))
+               ((unsigned char *)ret)[0] = cleanse_ctr;
+
        return ret;
        }
 
@@ -282,6 +289,7 @@ void CRYPTO_free_locked(void *str)
 void *CRYPTO_malloc(int num, const char *file, int line)
        {
        void *ret = NULL;
+       extern unsigned char cleanse_ctr;
 
        allow_customize = 0;
        if (malloc_debug_func != NULL)
@@ -296,6 +304,12 @@ void *CRYPTO_malloc(int num, const char *file, int line)
        if (malloc_debug_func != NULL)
                malloc_debug_func(ret, num, file, line, 1);
 
+        /* Create a dependency on the value of 'cleanse_ctr' so our memory
+         * sanitisation function can't be optimised out. NB: We only do
+         * this for >2Kb so the overhead doesn't bother us. */
+        if(ret && (num > 2048))
+                ((unsigned char *)ret)[0] = cleanse_ctr;
+
        return ret;
        }
 

diff --git a/util/libeay.num b/util/libeay.num
index 778b1618f84a62a3a369c89171a85512e3398e1d..81f5d31df95a0e03ae6e77cf64786bb47b075bd4 100755 (executable)
--- a/util/libeay.num
+++ b/util/libeay.num
@@ -2800,3 +2800,4 @@ BUF_strlcat                             3241      EXIST::FUNCTION:
 BIO_indent                              3242   EXIST::FUNCTION:
 BUF_strlcpy                             3243   EXIST::FUNCTION:
 OpenSSLDie                              3244   EXIST::FUNCTION:
+OPENSSL_cleanse                         3245   EXIST::FUNCTION: