Modify the DEVRANDOM source so that the files are kept open persistently. (c7504aeb) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP OpenSSL

CHANGES

+7 −0

Original line number	Diff line number	Diff line
		@@ -9,6 +9,13 @@

		Changes between 1.1.0h and 1.1.1 [xx XXX xxxx]

		*) Modified the random device based seed sources to keep the relevant
		file descriptors open rather than reopening them on each access.
		This allows such sources to operate in a chroot() jail without
		the associated device nodes being available. This behaviour can be
		controlled using RAND_keep_random_devices_open().
		[Paul Dale]

		*) Numerous side-channel attack mitigations have been applied. This may have
		performance impacts for some algorithms for the benefit of improved
		security. Specific changes are noted in this change log by their respective

crypto/include/internal/rand_int.h

+17 −0

Original line number	Diff line number	Diff line
		@@ -111,4 +111,21 @@ int rand_pool_add_nonce_data(RAND_POOL *pool);
		*/
		int rand_pool_add_additional_data(RAND_POOL *pool);

		/*
		* Initialise the random pool reseeding sources.
		*
		* Returns 1 on success and 0 on failure.
		*/
		int rand_pool_init(void);

		/*
		* Finalise the random pool reseeding sources.
		*/
		void rand_pool_cleanup(void);

		/*
		* Control the random pool use of open file descriptors.
		*/
		void rand_pool_keep_random_devices_open(int keep);

		#endif

crypto/rand/rand_lib.c

+15 −0

Original line number	Diff line number	Diff line
		@@ -324,8 +324,13 @@ DEFINE_RUN_ONCE_STATIC(do_rand_init)
		if (rand_nonce_lock == NULL)
		goto err2;

		if (!rand_pool_init())
		goto err3;

		return 1;

		err3:
		rand_pool_cleanup();
		err2:
		CRYPTO_THREAD_lock_free(rand_meth_lock);
		rand_meth_lock = NULL;
		@@ -343,6 +348,7 @@ void rand_cleanup_int(void)

		if (meth != NULL && meth->cleanup != NULL)
		meth->cleanup();
		rand_pool_cleanup();
		RAND_set_rand_method(NULL);
		#ifndef OPENSSL_NO_ENGINE
		CRYPTO_THREAD_lock_free(rand_engine_lock);
		@@ -354,6 +360,15 @@ void rand_cleanup_int(void)
		rand_nonce_lock = NULL;
		}

		/*
		* RAND_close_seed_files() ensures that any seed file decriptors are
		* closed after use.
		*/
		void RAND_keep_random_devices_open(int keep)
		{
		rand_pool_keep_random_devices_open(keep);
		}

		/*
		* RAND_poll() reseeds the default RNG using random input
		*

crypto/rand/rand_unix.c

+156 −16

Original line number	Diff line number	Diff line
		@@ -30,6 +30,8 @@

		#if defined(OPENSSL_SYS_UNIX) \|\| defined(__DJGPP__)
		# include <sys/types.h>
		# include <sys/stat.h>
		# include <fcntl.h>
		# include <unistd.h>
		# include <sys/time.h>

		@@ -154,6 +156,14 @@ size_t rand_pool_acquire_entropy(RAND_POOL *pool)
		return rand_pool_entropy_available(pool);
		}

		void rand_pool_cleanup(void)
		{
		}

		void rand_pool_keep_random_devices_open(int keep)
		{
		}

		# else

		# if defined(OPENSSL_RAND_SEED_EGD) && \
		@@ -274,6 +284,134 @@ int syscall_random(void *buf, size_t buflen)
		return -1;
		}

		#if !defined(OPENSSL_RAND_SEED_NONE) && defined(OPENSSL_RAND_SEED_DEVRANDOM)
		static const char *random_device_paths[] = { DEVRANDOM };
		static struct random_device {
		int fd;
		dev_t dev;
		ino_t ino;
		mode_t mode;
		dev_t rdev;
		} random_devices[OSSL_NELEM(random_device_paths)];
		static int keep_random_devices_open = 1;

		/*
		* Verify that the file descriptor associated with the random source is
		* still valid. The rationale for doing this is the fact that it is not
		* uncommon for daemons to close all open file handles when daemonizing.
		* So the handle might have been closed or even reused for opening
		* another file.
		*/
		static int check_random_device(struct random_device * rd)
		{
		struct stat st;

		return rd->fd != -1
		&& fstat(rd->fd, &st) != -1
		&& rd->dev == st.st_dev
		&& rd->ino == st.st_ino
		&& ((rd->mode ^ st.st_mode) & ~(S_IRWXU \| S_IRWXG \| S_IRWXO)) == 0
		&& rd->rdev == st.st_rdev;
		}

		/*
		* Open a random device if required and return its file descriptor or -1 on error
		*/
		static int get_random_device(size_t n)
		{
		struct stat st;
		struct random_device * rd = &random_devices[n];

		/* reuse existing file descriptor if it is (still) valid */
		if (check_random_device(rd))
		return rd->fd;

		/* open the random device ... */
		if ((rd->fd = open(random_device_paths[n], O_RDONLY)) == -1)
		return rd->fd;

		/* ... and cache its relevant stat(2) data */
		if (fstat(rd->fd, &st) != -1) {
		rd->dev = st.st_dev;
		rd->ino = st.st_ino;
		rd->mode = st.st_mode;
		rd->rdev = st.st_rdev;
		} else {
		close(rd->fd);
		rd->fd = -1;
		}

		return rd->fd;
		}

		/*
		* Close a random device making sure it is a random device
		*/
		static void close_random_device(size_t n)
		{
		struct random_device * rd = &random_devices[n];

		if (check_random_device(rd))
		close(rd->fd);
		rd->fd = -1;
		}

		static void open_random_devices(void)
		{
		size_t i;

		for (i = 0; i < OSSL_NELEM(random_devices); i++)
		(void)get_random_device(i);
		}

		int rand_pool_init(void)
		{
		size_t i;

		for (i = 0; i < OSSL_NELEM(random_devices); i++)
		random_devices[i].fd = -1;
		open_random_devices();
		return 1;
		}

		void rand_pool_cleanup(void)
		{
		size_t i;

		for (i = 0; i < OSSL_NELEM(random_devices); i++)
		close_random_device(i);
		}

		void rand_pool_keep_random_devices_open(int keep)
		{
		if (keep)
		open_random_devices();
		else
		rand_pool_cleanup();
		keep_random_devices_open = keep;
		}

		# else /* defined(OPENSSL_RAND_SEED_NONE)
		* \|\| !defined(OPENSSL_RAND_SEED_DEVRANDOM)
		*/

		int rand_pool_init(void)
		{
		return 1;
		}

		void rand_pool_cleanup(void)
		{
		}

		void rand_pool_keep_random_devices_open(int keep)
		{
		}

		# endif /* !defined(OPENSSL_RAND_SEED_NONE)
		* && defined(OPENSSL_RAND_SEED_DEVRANDOM)
		*/

		/*
		* Try the various seeding methods in turn, exit when successful.
		*
		@@ -324,30 +462,33 @@ size_t rand_pool_acquire_entropy(RAND_POOL *pool)

		# ifdef OPENSSL_RAND_SEED_DEVRANDOM
		bytes_needed = rand_pool_bytes_needed(pool, 1 /entropy_factor/);
		if (bytes_needed > 0) {
		static const char *paths[] = { DEVRANDOM, NULL };
		FILE *fp;
		int i;
		{
		size_t i;

		for (i = 0; paths[i] != NULL; i++) {
		if ((fp = fopen(paths[i], "rb")) == NULL)
		for (i = 0; bytes_needed > 0 && i < OSSL_NELEM(random_device_paths); i++) {
		const int fd = get_random_device(i);

		if (fd == -1)
		continue;
		setbuf(fp, NULL);
		buffer = rand_pool_add_begin(pool, bytes_needed);
		if (buffer != NULL) {
		size_t bytes = 0;
		if (fread(buffer, 1, bytes_needed, fp) == bytes_needed)
		bytes = bytes_needed;
		const ssize_t n = read(fd, buffer, bytes_needed);

		rand_pool_add_end(pool, bytes, 8 * bytes);
		entropy_available = rand_pool_entropy_available(pool);
		if (n <= 0) {
		close_random_device(i);
		continue;
		}
		fclose(fp);
		if (entropy_available > 0)
		return entropy_available;

		rand_pool_add_end(pool, n, 8 * n);
		}
		if (!keep_random_devices_open)
		close_random_device(i);

		bytes_needed = rand_pool_bytes_needed(pool, 1 /entropy_factor/);
		}
		entropy_available = rand_pool_entropy_available(pool);
		if (entropy_available > 0)
		return entropy_available;
		}
		# endif

		@@ -433,7 +574,6 @@ int rand_pool_add_additional_data(RAND_POOL *pool)
		}



		/*
		* Get the current time with the highest possible resolution
		*

crypto/rand/rand_vms.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -507,4 +507,17 @@ int rand_pool_add_additional_data(RAND_POOL *pool)
		return rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0);
		}

		int rand_pool_init(void)
		{
		return 1;
		}

		void rand_pool_cleanup(void)
		{
		}

		void rand_pool_keep_random_devices_open(int keep)
		{
		}

		#endif