[PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Vitaly Chikunov]

After CRYPTO_secure_malloc_init OpenSSL will store private keys in
secure heap. This facility is only available since OpenSSL_1_1_0-pre1.

Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
---
Change from v1:
- Do not use setfbuf to disable buffering as this is not proven to be
  meaningful.
- Use secure heap for passwords too as suggested by Mimi Zohar.
- Fallback to OPENSSL_malloc for old OpenSSL as suggested by Mimi Zohar.
- Simplify logic of calling CRYPTO_secure_malloc_init (call it always on
  OpenSSL init.)
- Should be applied after Bruno Meneguele's "evmctl: fix memory leak in
  get_password" patch v2.

 src/evmctl.c | 143 ++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 118 insertions(+), 25 deletions(-)

diff --git a/src/evmctl.c b/src/evmctl.c
index 5f7c2b8..a27e0b9 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -59,6 +59,7 @@
 #include <assert.h>
 
 #include <openssl/asn1.h>
+#include <openssl/crypto.h>
 #include <openssl/sha.h>
 #include <openssl/pem.h>
 #include <openssl/hmac.h>
@@ -165,6 +166,24 @@ struct tpm_bank_info {
 static char *pcrfile[MAX_PCRFILE];
 static unsigned npcrfile;
 
+#if OPENSSL_VERSION_NUMBER <= 0x10100000
+#warning Your OpenSSL version is too old to have OPENSSL_secure_malloc, \
+	falling back to use plain OPENSSL_malloc.
+#define OPENSSL_secure_malloc	  OPENSSL_malloc
+#define OPENSSL_secure_free	  OPENSSL_free
+/*
+ * Secure heap memory automatically cleared on free, but
+ * OPENSSL_secure_clear_free will be used in case of fallback
+ * to plain OPENSSL_malloc.
+ */
+#define OPENSSL_secure_clear_free OPENSSL_clear_free
+#define OPENSSL_clear_free(ptr, num)		\
+	do {					\
+		OPENSSL_cleanse(ptr, num);	\
+		OPENSSL_free(ptr);		\
+	} while (0)
+#endif
+
 static int bin2file(const char *file, const char *ext, const unsigned char *data, int len)
 {
 	FILE *fp;
@@ -188,7 +207,9 @@ static int bin2file(const char *file, const char *ext, const unsigned char *data
 	return err;
 }
 
-static unsigned char *file2bin(const char *file, const char *ext, int *size)
+/* Return data in OpenSSL secure heap if 'secure' is true. */
+static unsigned char *file2bin(const char *file, const char *ext, int *size,
+			       int secure)
 {
 	FILE *fp;
 	size_t len;
@@ -215,7 +236,10 @@ static unsigned char *file2bin(const char *file, const char *ext, int *size)
 	}
 	len = stats.st_size;
 
-	data = malloc(len);
+	if (secure)
+		data = OPENSSL_secure_malloc(len);
+	else
+		data = malloc(len);
 	if (!data) {
 		log_err("Failed to malloc %zu bytes: %s\n", len, name);
 		fclose(fp);
@@ -224,7 +248,10 @@ static unsigned char *file2bin(const char *file, const char *ext, int *size)
 	if (fread(data, len, 1, fp) != 1) {
 		log_err("Failed to fread %zu bytes: %s\n", len, name);
 		fclose(fp);
-		free(data);
+		if (secure)
+			OPENSSL_secure_clear_free(data, len);
+		else
+			free(data);
 		return NULL;
 	}
 	fclose(fp);
@@ -872,7 +899,7 @@ static int verify_ima(const char *file)
 	int len;
 
 	if (sigfile) {
-		void *tmp = file2bin(file, "sig", &len);
+		void *tmp = file2bin(file, "sig", &len, 0);
 
 		if (!tmp) {
 			log_err("Failed reading: %s\n", file);
@@ -1001,7 +1028,7 @@ static int cmd_import(struct command *cmd)
 
 		if (!pkey)
 			return 1;
-		pub = file2bin(inkey, NULL, &len);
+		pub = file2bin(inkey, NULL, &len, 0);
 		if (!pub) {
 			EVP_PKEY_free(pkey);
 			return 1;
@@ -1040,9 +1067,9 @@ static int setxattr_ima(const char *file, char *sig_file)
 	int len, err;
 
 	if (sig_file)
-		sig = file2bin(sig_file, NULL, &len);
+		sig = file2bin(sig_file, NULL, &len, 0);
 	else
-		sig = file2bin(file, "sig", &len);
+		sig = file2bin(file, "sig", &len, 0);
 	if (!sig)
 		return 0;
 
@@ -1082,9 +1109,9 @@ static int calc_evm_hmac(const char *file, const char *keyfile, unsigned char *h
 	unsigned int mdlen;
 	char **xattrname;
 	unsigned char xattr_value[1024];
-	unsigned char *key;
+	unsigned char *key; /* @secure heap */
 	int keylen;
-	unsigned char evmkey[MAX_KEY_SIZE];
+	unsigned char *evmkey; /* @secure heap */
 	char list[1024];
 	ssize_t list_size;
 	struct h_misc_64 hmac_misc;
@@ -1096,21 +1123,30 @@ static int calc_evm_hmac(const char *file, const char *keyfile, unsigned char *h
 	pctx = HMAC_CTX_new();
 #endif
 
-	key = file2bin(keyfile, NULL, &keylen);
+	key = file2bin(keyfile, NULL, &keylen, 1);
 	if (!key) {
 		log_err("Failed to read a key: %s\n", keyfile);
 		return -1;
 	}
 
-	if (keylen > sizeof(evmkey)) {
+	evmkey = OPENSSL_secure_malloc(MAX_KEY_SIZE);
+	if (!evmkey) {
+		log_err("Failed to allocate %d bytes\n", MAX_KEY_SIZE);
+		goto out;
+	}
+
+	if (keylen > MAX_KEY_SIZE) {
 		log_err("key is too long: %d\n", keylen);
 		goto out;
 	}
 
 	/* EVM key is 128 bytes */
 	memcpy(evmkey, key, keylen);
-	if (keylen < sizeof(evmkey))
-		memset(evmkey + keylen, 0, sizeof(evmkey) - keylen);
+	if (keylen < MAX_KEY_SIZE)
+		memset(evmkey + keylen, 0, MAX_KEY_SIZE - keylen);
+
+	/* Shorten lifetime of key data. */
+	OPENSSL_cleanse(key, keylen);
 
 	if (lstat(file, &st)) {
 		log_err("Failed to stat: %s\n", file);
@@ -1147,12 +1183,15 @@ static int calc_evm_hmac(const char *file, const char *keyfile, unsigned char *h
 		goto out;
 	}
 
-	err = !HMAC_Init_ex(pctx, evmkey, sizeof(evmkey), md, NULL);
+	err = !HMAC_Init_ex(pctx, evmkey, MAX_KEY_SIZE, md, NULL);
 	if (err) {
 		log_err("HMAC_Init() failed\n");
 		goto out;
 	}
 
+	/* Shorten lifetime of evmkey data. */
+	OPENSSL_cleanse(evmkey, MAX_KEY_SIZE);
+
 	for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) {
 		err = lgetxattr(file, *xattrname, xattr_value, sizeof(xattr_value));
 		if (err < 0) {
@@ -1222,7 +1261,9 @@ out_ctx_cleanup:
 	HMAC_CTX_free(pctx);
 #endif
 out:
-	free(key);
+	if (evmkey)
+		OPENSSL_secure_clear_free(evmkey, MAX_KEY_SIZE);
+	OPENSSL_secure_clear_free(key, keylen);
 	return err ?: mdlen;
 }
 
@@ -2596,15 +2637,41 @@ static struct option opts[] = {
 
 };
 
+/*
+ * Copy password from optarg into secure heap, so it could be
+ * freed in the same way as a result of get_password().
+ */
+static char *optarg_password(char *optarg)
+{
+	size_t len;
+	char *keypass;
+
+	if (!optarg)
+		return NULL;
+	len = strlen(optarg);
+	keypass = OPENSSL_secure_malloc(len + 1);
+	if (keypass)
+		memcpy(keypass, optarg, len + 1);
+	else
+		perror("OPENSSL_secure_malloc");
+	/*
+	 * This memset does not add real security, just increases
+	 * the chance of password being obscured in ps output.
+	 */
+	memset(optarg, 'X', len);
+	return keypass;
+}
+
+/* Read from TTY into secure heap. */
 static char *get_password(void)
 {
 	struct termios flags, tmp_flags;
 	char *password, *pwd;
-	int passlen = 64;
+	const int passlen = 64;
 
-	password = malloc(passlen);
+	password = OPENSSL_secure_malloc(passlen);
 	if (!password) {
-		perror("malloc");
+		perror("OPENSSL_secure_malloc");
 		return NULL;
 	}
 
@@ -2615,7 +2682,7 @@ static char *get_password(void)
 
 	if (tcsetattr(fileno(stdin), TCSANOW, &tmp_flags) != 0) {
 		perror("tcsetattr");
-		free(password);
+		OPENSSL_secure_free(password);
 		return NULL;
 	}
 
@@ -2625,12 +2692,14 @@ static char *get_password(void)
 	/* restore terminal */
 	if (tcsetattr(fileno(stdin), TCSANOW, &flags) != 0) {
 		perror("tcsetattr");
-		free(password);
-		return NULL;
+		/*
+		 * Password is already here, so there is no point
+		 * to stop working on this petty error.
+		 */
 	}
 
 	if (pwd == NULL) {
-		free(password);
+		OPENSSL_secure_free(password);
 		return NULL;
 	}
 
@@ -2643,6 +2712,7 @@ int main(int argc, char *argv[])
 	ENGINE *eng = NULL;
 	unsigned long keyid;
 	char *eptr;
+	char *keypass = NULL; /* @secure heap */
 
 #if !(OPENSSL_VERSION_NUMBER < 0x10100000)
 	OPENSSL_init_crypto(
@@ -2651,6 +2721,16 @@ int main(int argc, char *argv[])
 #endif
 			    OPENSSL_INIT_ENGINE_ALL_BUILTIN, NULL);
 #endif
+#if OPENSSL_VERSION_NUMBER > 0x10100000
+	/*
+	 * This facility is available since OpenSSL_1_1_0-pre1.
+	 * 'Heap size' 8192 is chosen to be big enough, so that any single key
+	 * data could fit. 'Heap minsize' 64 is just to be efficient for small
+	 * buffers.
+	 */
+       CRYPTO_secure_malloc_init(8192, 64);
+#endif
+
 	g_argv = argv;
 	g_argc = argc;
 
@@ -2682,10 +2762,18 @@ int main(int argc, char *argv[])
 			imaevm_params.hash_algo = optarg;
 			break;
 		case 'p':
+			if (keypass)
+				OPENSSL_secure_clear_free(keypass,
+							  strlen(keypass));
 			if (optarg)
-				imaevm_params.keypass = optarg;
+				keypass = optarg_password(optarg);
 			else
-				imaevm_params.keypass = get_password();
+				keypass = get_password();
+			if (!keypass) {
+				log_err("Cannot read password\n");
+				goto quit;
+			}
+			imaevm_params.keypass = keypass;
 			break;
 		case 'f':
 			sigfile = 1;
@@ -2841,7 +2929,9 @@ int main(int argc, char *argv[])
 		if (err < 0)
 			err = 125;
 	}
-
+quit:
+	if (keypass)
+		OPENSSL_secure_clear_free(keypass, strlen(keypass));
 	if (eng) {
 		ENGINE_finish(eng);
 		ENGINE_free(eng);
@@ -2849,6 +2939,9 @@ int main(int argc, char *argv[])
 		ENGINE_cleanup();
 #endif
 	}
+#if OPENSSL_VERSION_NUMBER > 0x10100000
+	CRYPTO_secure_malloc_done();
+#endif
 	ERR_free_strings();
 	EVP_cleanup();
 	BIO_free(NULL);
-- 
2.29.3

Re: [PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Mimi Zohar]

On Thu, 2021-08-19 at 05:11 +0300, Vitaly Chikunov wrote:
> After CRYPTO_secure_malloc_init OpenSSL will store private keys in
> secure heap. This facility is only available since OpenSSL_1_1_0-pre1.
> 
> Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
> ---
> Change from v1:
> - Do not use setfbuf to disable buffering as this is not proven to be
>   meaningful.
> - Use secure heap for passwords too as suggested by Mimi Zohar.
> - Fallback to OPENSSL_malloc for old OpenSSL as suggested by Mimi Zohar.
> - Simplify logic of calling CRYPTO_secure_malloc_init (call it always on
>   OpenSSL init.)
> - Should be applied after Bruno Meneguele's "evmctl: fix memory leak in
>   get_password" patch v2.

Not sure why it isn't applying with/without Bruno's v2 patch.

> 
>  src/evmctl.c | 143 ++++++++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 118 insertions(+), 25 deletions(-)
> 
> diff --git a/src/evmctl.c b/src/evmctl.c

> @@ -188,7 +207,9 @@ static int bin2file(const char *file, const char *ext, const unsigned char *data
>  	return err;
>  }
> 
> -static unsigned char *file2bin(const char *file, const char *ext, int *size)
> +/* Return data in OpenSSL secure heap if 'secure' is true. */
> +static unsigned char *file2bin(const char *file, const char *ext, int *size,
> +			       int secure)
>  {
>  	FILE *fp;
>  	size_t len;
> @@ -215,7 +236,10 @@ static unsigned char *file2bin(const char *file, const char *ext, int *size)
>  	}
>  	len = stats.st_size;
> 
> -	data = malloc(len);
> +	if (secure)
> +		data = OPENSSL_secure_malloc(len);
> +	else
> +		data = malloc(len);

Without being able to apply the patch, it's hard to tell if there
should be a preparatory patch that first replaces malloc() with
OPENSSL_malloc(), and other similar changes.

thanks,

Mimi

>  	if (!data) {
>  		log_err("Failed to malloc %zu bytes: %s\n", len, name);
>  		fclose(fp);

Re: [PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Vitaly Chikunov]

Mimi,

On Thu, Aug 19, 2021 at 02:06:03PM -0400, Mimi Zohar wrote:
> On Thu, 2021-08-19 at 05:11 +0300, Vitaly Chikunov wrote:
> > After CRYPTO_secure_malloc_init OpenSSL will store private keys in
> > secure heap. This facility is only available since OpenSSL_1_1_0-pre1.
> > 
> > Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
> > ---
> > Change from v1:
> > - Do not use setfbuf to disable buffering as this is not proven to be
> >   meaningful.
> > - Use secure heap for passwords too as suggested by Mimi Zohar.
> > - Fallback to OPENSSL_malloc for old OpenSSL as suggested by Mimi Zohar.
> > - Simplify logic of calling CRYPTO_secure_malloc_init (call it always on
> >   OpenSSL init.)
> > - Should be applied after Bruno Meneguele's "evmctl: fix memory leak in
> >   get_password" patch v2.
> 
> Not sure why it isn't applying with/without Bruno's v2 patch.

It should be over next-testing + (manually git am'ed) Bruno's patch:

  db25fcd 2021-08-19 03:20:48 +0300 Use secure heap for private keys and passwords (Vitaly Chikunov)
  d37ea6d 2021-08-16 12:15:59 -0300 evmctl: fix memory leak in get_password (Bruno Meneguele)
  b1818c1 2021-08-03 16:40:08 -0400 Create alternative tpm2_pcr_read() that uses IBM TSS (Ken Goldman) (origin/next-testing)

> 
> > 
> >  src/evmctl.c | 143 ++++++++++++++++++++++++++++++++++++++++++---------
> >  1 file changed, 118 insertions(+), 25 deletions(-)
> > 
> > diff --git a/src/evmctl.c b/src/evmctl.c
> 
> > @@ -188,7 +207,9 @@ static int bin2file(const char *file, const char *ext, const unsigned char *data
> >  	return err;
> >  }
> > 
> > -static unsigned char *file2bin(const char *file, const char *ext, int *size)
> > +/* Return data in OpenSSL secure heap if 'secure' is true. */
> > +static unsigned char *file2bin(const char *file, const char *ext, int *size,
> > +			       int secure)
> >  {
> >  	FILE *fp;
> >  	size_t len;
> > @@ -215,7 +236,10 @@ static unsigned char *file2bin(const char *file, const char *ext, int *size)
> >  	}
> >  	len = stats.st_size;
> > 
> > -	data = malloc(len);
> > +	if (secure)
> > +		data = OPENSSL_secure_malloc(len);
> > +	else
> > +		data = malloc(len);
> 
> Without being able to apply the patch, it's hard to tell if there
> should be a preparatory patch that first replaces malloc() with
> OPENSSL_malloc(), and other similar changes.

There is no OPENSSL_malloc use and I don't see why it should be.

Thanks,

> 
> thanks,
> 
> Mimi
> 
> >  	if (!data) {
> >  		log_err("Failed to malloc %zu bytes: %s\n", len, name);
> >  		fclose(fp);

Re: [PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Bruno Meneguele]

[-- Attachment #1: Type: text/plain, Size: 3024 bytes --]

On Thu, Aug 19, 2021 at 09:12:25PM +0300, Vitaly Chikunov wrote:
> Mimi,
> 
> On Thu, Aug 19, 2021 at 02:06:03PM -0400, Mimi Zohar wrote:
> > On Thu, 2021-08-19 at 05:11 +0300, Vitaly Chikunov wrote:
> > > After CRYPTO_secure_malloc_init OpenSSL will store private keys in
> > > secure heap. This facility is only available since OpenSSL_1_1_0-pre1.
> > > 
> > > Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
> > > ---
> > > Change from v1:
> > > - Do not use setfbuf to disable buffering as this is not proven to be
> > >   meaningful.
> > > - Use secure heap for passwords too as suggested by Mimi Zohar.
> > > - Fallback to OPENSSL_malloc for old OpenSSL as suggested by Mimi Zohar.
> > > - Simplify logic of calling CRYPTO_secure_malloc_init (call it always on
> > >   OpenSSL init.)
> > > - Should be applied after Bruno Meneguele's "evmctl: fix memory leak in
> > >   get_password" patch v2.
> > 
> > Not sure why it isn't applying with/without Bruno's v2 patch.
> 
> It should be over next-testing + (manually git am'ed) Bruno's patch:
> 
>   db25fcd 2021-08-19 03:20:48 +0300 Use secure heap for private keys and passwords (Vitaly Chikunov)
>   d37ea6d 2021-08-16 12:15:59 -0300 evmctl: fix memory leak in get_password (Bruno Meneguele)
>   b1818c1 2021-08-03 16:40:08 -0400 Create alternative tpm2_pcr_read() that uses IBM TSS (Ken Goldman) (origin/next-testing)
> 
> > 
> > > 
> > >  src/evmctl.c | 143 ++++++++++++++++++++++++++++++++++++++++++---------
> > >  1 file changed, 118 insertions(+), 25 deletions(-)
> > > 
> > > diff --git a/src/evmctl.c b/src/evmctl.c
> > 
> > > @@ -188,7 +207,9 @@ static int bin2file(const char *file, const char *ext, const unsigned char *data
> > >  	return err;
> > >  }
> > > 
> > > -static unsigned char *file2bin(const char *file, const char *ext, int *size)
> > > +/* Return data in OpenSSL secure heap if 'secure' is true. */
> > > +static unsigned char *file2bin(const char *file, const char *ext, int *size,
> > > +			       int secure)
> > >  {
> > >  	FILE *fp;
> > >  	size_t len;
> > > @@ -215,7 +236,10 @@ static unsigned char *file2bin(const char *file, const char *ext, int *size)
> > >  	}
> > >  	len = stats.st_size;
> > > 
> > > -	data = malloc(len);
> > > +	if (secure)
> > > +		data = OPENSSL_secure_malloc(len);
> > > +	else
> > > +		data = malloc(len);
> > 
> > Without being able to apply the patch, it's hard to tell if there
> > should be a preparatory patch that first replaces malloc() with
> > OPENSSL_malloc(), and other similar changes.
> 
> There is no OPENSSL_malloc use and I don't see why it should be.
> 

Keeping the OPENSSL_* calls as a meaning of "secure calls" while keeping
the standard C library calls for "non-secure" seems indeed cleaner.

> Thanks,
> 
> > 
> > thanks,
> > 
> > Mimi
> > 
> > >  	if (!data) {
> > >  		log_err("Failed to malloc %zu bytes: %s\n", len, name);
> > >  		fclose(fp);
> 

-- 
bmeneg 
PGP Key: http://bmeneg.com/pubkey.txt

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Mimi Zohar]

On Thu, 2021-08-19 at 15:27 -0300, Bruno Meneguele wrote:
> On Thu, Aug 19, 2021 at 09:12:25PM +0300, Vitaly Chikunov wrote:
> > > > @@ -215,7 +236,10 @@ static unsigned char *file2bin(const char *file, const char *ext, int *size)
> > > >  	}
> > > >  	len = stats.st_size;
> > > > 
> > > > -	data = malloc(len);
> > > > +	if (secure)
> > > > +		data = OPENSSL_secure_malloc(len);
> > > > +	else
> > > > +		data = malloc(len);
> > > 
> > > Without being able to apply the patch, it's hard to tell if there
> > > should be a preparatory patch that first replaces malloc() with
> > > OPENSSL_malloc(), and other similar changes.
> > 
> > There is no OPENSSL_malloc use and I don't see why it should be.
> > 
> 
> Keeping the OPENSSL_* calls as a meaning of "secure calls" while keeping
> the standard C library calls for "non-secure" seems indeed cleaner.

Ok

thanks,

Mimi

Re: [PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Mimi Zohar]

On Thu, 2021-08-19 at 21:12 +0300, Vitaly Chikunov wrote:
> Mimi,
> 
> On Thu, Aug 19, 2021 at 02:06:03PM -0400, Mimi Zohar wrote:
> > On Thu, 2021-08-19 at 05:11 +0300, Vitaly Chikunov wrote:
> > > After CRYPTO_secure_malloc_init OpenSSL will store private keys in
> > > secure heap. This facility is only available since OpenSSL_1_1_0-pre1.
> > > 
> > > Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
> > > ---
> > > Change from v1:
> > > - Do not use setfbuf to disable buffering as this is not proven to be
> > >   meaningful.
> > > - Use secure heap for passwords too as suggested by Mimi Zohar.
> > > - Fallback to OPENSSL_malloc for old OpenSSL as suggested by Mimi Zohar.
> > > - Simplify logic of calling CRYPTO_secure_malloc_init (call it always on
> > >   OpenSSL init.)
> > > - Should be applied after Bruno Meneguele's "evmctl: fix memory leak in
> > >   get_password" patch v2.
> > 
> > Not sure why it isn't applying with/without Bruno's v2 patch.
> 
> It should be over next-testing + (manually git am'ed) Bruno's patch:
> 
>   db25fcd 2021-08-19 03:20:48 +0300 Use secure heap for private keys and passwords (Vitaly Chikunov)
>   d37ea6d 2021-08-16 12:15:59 -0300 evmctl: fix memory leak in get_password (Bruno Meneguele)
>   b1818c1 2021-08-03 16:40:08 -0400 Create alternative tpm2_pcr_read() that uses IBM TSS (Ken Goldman) (origin/next-testing)

Sorry, my mistake.  Applied the wrong patch.

Mimi

Re: [PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Bruno Meneguele]

[-- Attachment #1: Type: text/plain, Size: 1860 bytes --]

On Thu, Aug 19, 2021 at 05:11:36AM +0300, Vitaly Chikunov wrote:
> After CRYPTO_secure_malloc_init OpenSSL will store private keys in
> secure heap. This facility is only available since OpenSSL_1_1_0-pre1.
> 
> Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
> ---
> Change from v1:
> - Do not use setfbuf to disable buffering as this is not proven to be
>   meaningful.
> - Use secure heap for passwords too as suggested by Mimi Zohar.
> - Fallback to OPENSSL_malloc for old OpenSSL as suggested by Mimi Zohar.
> - Simplify logic of calling CRYPTO_secure_malloc_init (call it always on
>   OpenSSL init.)
> - Should be applied after Bruno Meneguele's "evmctl: fix memory leak in
>   get_password" patch v2.
> 
>  src/evmctl.c | 143 ++++++++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 118 insertions(+), 25 deletions(-)
> 
> diff --git a/src/evmctl.c b/src/evmctl.c
> index 5f7c2b8..a27e0b9 100644
> --- a/src/evmctl.c
> +++ b/src/evmctl.c
> @@ -59,6 +59,7 @@
>  #include <assert.h>
>  
>  #include <openssl/asn1.h>
> +#include <openssl/crypto.h>
>  #include <openssl/sha.h>
>  #include <openssl/pem.h>
>  #include <openssl/hmac.h>
> @@ -165,6 +166,24 @@ struct tpm_bank_info {
>  static char *pcrfile[MAX_PCRFILE];
>  static unsigned npcrfile;
>  
> +#if OPENSSL_VERSION_NUMBER <= 0x10100000
> +#warning Your OpenSSL version is too old to have OPENSSL_secure_malloc, \
> +	falling back to use plain OPENSSL_malloc.
> +#define OPENSSL_secure_malloc	  OPENSSL_malloc
> +#define OPENSSL_secure_free	  OPENSSL_free
> +/*
> + * Secure heap memory automatically cleared on free, but
> + * OPENSSL_secure_clear_free will be used in case of fallback

Shouldn't it be OPENSSL_clear_free instead of OPENSLL_secure_clear_free
in the setence above?

-- 
bmeneg 
PGP Key: http://bmeneg.com/pubkey.txt

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Re: [PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Vitaly Chikunov]

Bruno,

On Thu, Aug 19, 2021 at 03:28:17PM -0300, Bruno Meneguele wrote:
> On Thu, Aug 19, 2021 at 05:11:36AM +0300, Vitaly Chikunov wrote:
> > After CRYPTO_secure_malloc_init OpenSSL will store private keys in
> > secure heap. This facility is only available since OpenSSL_1_1_0-pre1.
> > 
> > Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
> > ---
> > Change from v1:
> > - Do not use setfbuf to disable buffering as this is not proven to be
> >   meaningful.
> > - Use secure heap for passwords too as suggested by Mimi Zohar.
> > - Fallback to OPENSSL_malloc for old OpenSSL as suggested by Mimi Zohar.
> > - Simplify logic of calling CRYPTO_secure_malloc_init (call it always on
> >   OpenSSL init.)
> > - Should be applied after Bruno Meneguele's "evmctl: fix memory leak in
> >   get_password" patch v2.
> > 
> >  src/evmctl.c | 143 ++++++++++++++++++++++++++++++++++++++++++---------
> >  1 file changed, 118 insertions(+), 25 deletions(-)
> > 
> > diff --git a/src/evmctl.c b/src/evmctl.c
> > index 5f7c2b8..a27e0b9 100644
> > --- a/src/evmctl.c
> > +++ b/src/evmctl.c
> > @@ -59,6 +59,7 @@
> >  #include <assert.h>
> >  
> >  #include <openssl/asn1.h>
> > +#include <openssl/crypto.h>
> >  #include <openssl/sha.h>
> >  #include <openssl/pem.h>
> >  #include <openssl/hmac.h>
> > @@ -165,6 +166,24 @@ struct tpm_bank_info {
> >  static char *pcrfile[MAX_PCRFILE];
> >  static unsigned npcrfile;
> >  
> > +#if OPENSSL_VERSION_NUMBER <= 0x10100000
> > +#warning Your OpenSSL version is too old to have OPENSSL_secure_malloc, \
> > +	falling back to use plain OPENSSL_malloc.
> > +#define OPENSSL_secure_malloc	  OPENSSL_malloc
> > +#define OPENSSL_secure_free	  OPENSSL_free
> > +/*
> > + * Secure heap memory automatically cleared on free, but
> > + * OPENSSL_secure_clear_free will be used in case of fallback
> 
> Shouldn't it be OPENSSL_clear_free instead of OPENSLL_secure_clear_free
> in the setence above?

No. I meant our code will use OPENSSL_secure_clear_free, so when there
is no secure heap it will fallback to OPENSSL_clear_free (and not just
to OPENSSL_free if we used OPENSSL_secure_free).

Thanks,

> 
> -- 
> bmeneg 
> PGP Key: http://bmeneg.com/pubkey.txt

Re: [PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Bruno Meneguele]

[-- Attachment #1: Type: text/plain, Size: 2594 bytes --]

On Fri, Aug 20, 2021 at 01:04:45AM +0300, Vitaly Chikunov wrote:
> Bruno,
> 
> On Thu, Aug 19, 2021 at 03:28:17PM -0300, Bruno Meneguele wrote:
> > On Thu, Aug 19, 2021 at 05:11:36AM +0300, Vitaly Chikunov wrote:
> > > After CRYPTO_secure_malloc_init OpenSSL will store private keys in
> > > secure heap. This facility is only available since OpenSSL_1_1_0-pre1.
> > > 
> > > Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
> > > ---
> > > Change from v1:
> > > - Do not use setfbuf to disable buffering as this is not proven to be
> > >   meaningful.
> > > - Use secure heap for passwords too as suggested by Mimi Zohar.
> > > - Fallback to OPENSSL_malloc for old OpenSSL as suggested by Mimi Zohar.
> > > - Simplify logic of calling CRYPTO_secure_malloc_init (call it always on
> > >   OpenSSL init.)
> > > - Should be applied after Bruno Meneguele's "evmctl: fix memory leak in
> > >   get_password" patch v2.
> > > 
> > >  src/evmctl.c | 143 ++++++++++++++++++++++++++++++++++++++++++---------
> > >  1 file changed, 118 insertions(+), 25 deletions(-)
> > > 
> > > diff --git a/src/evmctl.c b/src/evmctl.c
> > > index 5f7c2b8..a27e0b9 100644
> > > --- a/src/evmctl.c
> > > +++ b/src/evmctl.c
> > > @@ -59,6 +59,7 @@
> > >  #include <assert.h>
> > >  
> > >  #include <openssl/asn1.h>
> > > +#include <openssl/crypto.h>
> > >  #include <openssl/sha.h>
> > >  #include <openssl/pem.h>
> > >  #include <openssl/hmac.h>
> > > @@ -165,6 +166,24 @@ struct tpm_bank_info {
> > >  static char *pcrfile[MAX_PCRFILE];
> > >  static unsigned npcrfile;
> > >  
> > > +#if OPENSSL_VERSION_NUMBER <= 0x10100000
> > > +#warning Your OpenSSL version is too old to have OPENSSL_secure_malloc, \
> > > +	falling back to use plain OPENSSL_malloc.
> > > +#define OPENSSL_secure_malloc	  OPENSSL_malloc
> > > +#define OPENSSL_secure_free	  OPENSSL_free
> > > +/*
> > > + * Secure heap memory automatically cleared on free, but
> > > + * OPENSSL_secure_clear_free will be used in case of fallback
> > 
> > Shouldn't it be OPENSSL_clear_free instead of OPENSLL_secure_clear_free
> > in the setence above?
> 
> No. I meant our code will use OPENSSL_secure_clear_free, so when there
> is no secure heap it will fallback to OPENSSL_clear_free (and not just
> to OPENSSL_free if we used OPENSSL_secure_free).
> 
> Thanks,
> 

Ah ok, I misread the sentence.
Thanks for the clarification.

It seems you'll send a new version of the patch, right?
Will review that as soon as it lands.

Many thanks.

-- 
bmeneg 
PGP Key: http://bmeneg.com/pubkey.txt

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Re: [PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Vitaly Chikunov]

On Thu, Aug 19, 2021 at 05:11:36AM +0300, Vitaly Chikunov wrote:
> After CRYPTO_secure_malloc_init OpenSSL will store private keys in
> secure heap. This facility is only available since OpenSSL_1_1_0-pre1.
> 
> Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
> ---
> Change from v1:
> - Do not use setfbuf to disable buffering as this is not proven to be
>   meaningful.
> - Use secure heap for passwords too as suggested by Mimi Zohar.
> - Fallback to OPENSSL_malloc for old OpenSSL as suggested by Mimi Zohar.
> - Simplify logic of calling CRYPTO_secure_malloc_init (call it always on
>   OpenSSL init.)
> - Should be applied after Bruno Meneguele's "evmctl: fix memory leak in
>   get_password" patch v2.
> 
>  src/evmctl.c | 143 ++++++++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 118 insertions(+), 25 deletions(-)
> 
> @@ -2651,6 +2721,16 @@ int main(int argc, char *argv[])
>  #endif
>  			    OPENSSL_INIT_ENGINE_ALL_BUILTIN, NULL);
>  #endif
> +#if OPENSSL_VERSION_NUMBER > 0x10100000
> +	/*
> +	 * This facility is available since OpenSSL_1_1_0-pre1.
> +	 * 'Heap size' 8192 is chosen to be big enough, so that any single key
> +	 * data could fit. 'Heap minsize' 64 is just to be efficient for small
> +	 * buffers.
> +	 */
> +       CRYPTO_secure_malloc_init(8192, 64);
> +#endif

Forgot to check return value of this.

Thanks,

Re: [PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Vitaly Chikunov]

On Thu, Aug 19, 2021 at 05:11:36AM +0300, Vitaly Chikunov wrote:
> After CRYPTO_secure_malloc_init OpenSSL will store private keys in
> secure heap. This facility is only available since OpenSSL_1_1_0-pre1.
> 
> Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
> ---
> Change from v1:
> - Do not use setfbuf to disable buffering as this is not proven to be
>   meaningful.
> - Use secure heap for passwords too as suggested by Mimi Zohar.
> - Fallback to OPENSSL_malloc for old OpenSSL as suggested by Mimi Zohar.
> - Simplify logic of calling CRYPTO_secure_malloc_init (call it always on
>   OpenSSL init.)
> - Should be applied after Bruno Meneguele's "evmctl: fix memory leak in
>   get_password" patch v2.
> 
>  src/evmctl.c | 143 ++++++++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 118 insertions(+), 25 deletions(-)
> 
> @@ -2596,15 +2637,41 @@ static struct option opts[] = {
>  
>  };
>  
> +/*
> + * Copy password from optarg into secure heap, so it could be
> + * freed in the same way as a result of get_password().
> + */
> +static char *optarg_password(char *optarg)
> +{
> +	size_t len;
> +	char *keypass;
> +
> +	if (!optarg)
> +		return NULL;
> +	len = strlen(optarg);
> +	keypass = OPENSSL_secure_malloc(len + 1);
> +	if (keypass)
> +		memcpy(keypass, optarg, len + 1);
> +	else
> +		perror("OPENSSL_secure_malloc");

I also realized that OPENSSL_secure_malloc does not (intentionally)
set errno, so using perror is perhaps wrong. Better method should be
thanked out.

> +	/*
> +	 * This memset does not add real security, just increases
> +	 * the chance of password being obscured in ps output.
> +	 */
> +	memset(optarg, 'X', len);
> +	return keypass;
> +}
> +
> +/* Read from TTY into secure heap. */
>  static char *get_password(void)
>  {
>  	struct termios flags, tmp_flags;
>  	char *password, *pwd;
> -	int passlen = 64;
> +	const int passlen = 64;
>  
> -	password = malloc(passlen);
> +	password = OPENSSL_secure_malloc(passlen);
>  	if (!password) {
> -		perror("malloc");
> +		perror("OPENSSL_secure_malloc");

Thanks,

>  		return NULL;
>  	}
>  

Re: [PATCH ima-evm-utils v2] Use secure heap for private keys and passwords

[Vitaly Chikunov]

On Fri, Aug 20, 2021 at 12:42:26AM +0300, Vitaly Chikunov wrote:
> On Thu, Aug 19, 2021 at 05:11:36AM +0300, Vitaly Chikunov wrote:
> > After CRYPTO_secure_malloc_init OpenSSL will store private keys in
> > secure heap. This facility is only available since OpenSSL_1_1_0-pre1.
> > 
> > Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
> > ---
> > Change from v1:
> > - Do not use setfbuf to disable buffering as this is not proven to be
> >   meaningful.
> > - Use secure heap for passwords too as suggested by Mimi Zohar.
> > - Fallback to OPENSSL_malloc for old OpenSSL as suggested by Mimi Zohar.
> > - Simplify logic of calling CRYPTO_secure_malloc_init (call it always on
> >   OpenSSL init.)
> > - Should be applied after Bruno Meneguele's "evmctl: fix memory leak in
> >   get_password" patch v2.
> > 
> >  src/evmctl.c | 143 ++++++++++++++++++++++++++++++++++++++++++---------
> >  1 file changed, 118 insertions(+), 25 deletions(-)
> > 
> > @@ -2596,15 +2637,41 @@ static struct option opts[] = {
> >  
> >  };
> >  
> > +/*
> > + * Copy password from optarg into secure heap, so it could be
> > + * freed in the same way as a result of get_password().
> > + */
> > +static char *optarg_password(char *optarg)
> > +{
> > +	size_t len;
> > +	char *keypass;
> > +
> > +	if (!optarg)
> > +		return NULL;
> > +	len = strlen(optarg);
> > +	keypass = OPENSSL_secure_malloc(len + 1);
> > +	if (keypass)
> > +		memcpy(keypass, optarg, len + 1);
> > +	else
> > +		perror("OPENSSL_secure_malloc");
> 
> I also realized that OPENSSL_secure_malloc does not (intentionally)
> set errno, so using perror is perhaps wrong. Better method should be
> thanked out.

After some more thinking I think all this perror usage should be
replaced with log_err like in all other places. (perror is used only in
get_password). Log_err hypothetically could log to stdout or to syslog
depending on USE_FPRINTF(*), but perror will always log to stderr.

  (*) Which is _always_ defined though. This is obscure.

Thanks,