#include <stdio.h>
#include "internal/cryptlib.h"
#include <openssl/rand.h>
+#include <openssl/crypto.h>
#include "rand_lcl.h"
#include "internal/rand_int.h"
#include <stdio.h>
#include "internal/dso.h"
-#if defined(__linux)
-# include <asm/unistd.h>
+#ifdef __linux
+# include <sys/syscall.h>
+# ifdef DEVRANDOM_WAIT
+# include <sys/shm.h>
+# include <sys/utsname.h>
+# endif
#endif
-#if defined(__FreeBSD__)
+#if defined(__FreeBSD__) && !defined(OPENSSL_SYS_UEFI)
# include <sys/types.h>
# include <sys/sysctl.h>
# include <sys/param.h>
# endif
# if defined(OPENSSL_RAND_SEED_GETRANDOM)
+
+# if defined(__linux) && !defined(__NR_getrandom)
+# if defined(__arm__) && defined(__NR_SYSCALL_BASE)
+# define __NR_getrandom (__NR_SYSCALL_BASE+384)
+# elif defined(__i386__)
+# define __NR_getrandom 355
+# elif defined(__x86_64__) && !defined(__ILP32__)
+# define __NR_getrandom 318
+# endif
+# endif
+
/*
* syscall_random(): Try to get random data using a system call
* returns the number of bytes returned in buf, or < 0 on error.
if (getentropy != NULL)
return getentropy(buf, buflen) == 0 ? (ssize_t)buflen : -1;
-# else
+# elif !defined(FIPS_MODE)
union {
void *p;
int (*f)(void *buffer, size_t length);
} random_devices[OSSL_NELEM(random_device_paths)];
static int keep_random_devices_open = 1;
+# if defined(__linux) && defined(DEVRANDOM_WAIT)
+static void *shm_addr;
+
+# if !defined(FIPS_MODE)
+static void cleanup_shm(void)
+{
+ shmdt(shm_addr);
+}
+# endif
+
+/*
+ * Ensure that the system randomness source has been adequately seeded.
+ * This is done by having the first start of libcrypto, wait until the device
+ * /dev/random becomes able to supply a byte of entropy. Subsequent starts
+ * of the library and later reseedings do not need to do this.
+ */
+static int wait_random_seeded(void)
+{
+ static int seeded = OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID < 0;
+ static const int kernel_version[] = { DEVRANDOM_SAFE_KERNEL };
+ int kernel[2];
+ int shm_id, fd, r;
+ char c, *p;
+ struct utsname un;
+ fd_set fds;
+
+ if (!seeded) {
+ /* See if anything has created the global seeded indication */
+ if ((shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1, 0)) == -1) {
+ /*
+ * Check the kernel's version and fail if it is too recent.
+ *
+ * Linux kernels from 4.8 onwards do not guarantee that
+ * /dev/urandom is properly seeded when /dev/random becomes
+ * readable. However, such kernels support the getentropy(2)
+ * system call and this should always succeed which renders
+ * this alternative but essentially identical source moot.
+ */
+ if (uname(&un) == 0) {
+ kernel[0] = atoi(un.release);
+ p = strchr(un.release, '.');
+ kernel[1] = p == NULL ? 0 : atoi(p + 1);
+ if (kernel[0] > kernel_version[0]
+ || (kernel[0] == kernel_version[0]
+ && kernel[1] >= kernel_version[1])) {
+ return 0;
+ }
+ }
+ /* Open /dev/random and wait for it to be readable */
+ if ((fd = open(DEVRANDOM_WAIT, O_RDONLY)) != -1) {
+ if (DEVRANDM_WAIT_USE_SELECT && fd < FD_SETSIZE) {
+ FD_ZERO(&fds);
+ FD_SET(fd, &fds);
+ while ((r = select(fd + 1, &fds, NULL, NULL, NULL)) < 0
+ && errno == EINTR);
+ } else {
+ while ((r = read(fd, &c, 1)) < 0 && errno == EINTR);
+ }
+ close(fd);
+ if (r == 1) {
+ seeded = 1;
+ /* Create the shared memory indicator */
+ shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1,
+ IPC_CREAT | S_IRUSR | S_IRGRP | S_IROTH);
+ }
+ }
+ }
+ if (shm_id != -1) {
+ seeded = 1;
+ /*
+ * Map the shared memory to prevent its premature destruction.
+ * If this call fails, it isn't a big problem.
+ */
+ shm_addr = shmat(shm_id, NULL, SHM_RDONLY);
+# ifndef FIPS_MODE
+ /* TODO 3.0: The FIPS provider doesn't have OPENSSL_atexit */
+ if (shm_addr != (void *)-1)
+ OPENSSL_atexit(&cleanup_shm);
+# endif
+ }
+ }
+ return seeded;
+}
+# else /* defined __linux */
+static int wait_random_seeded(void)
+{
+ return 1;
+}
+# endif
+
/*
* 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
# if defined(OPENSSL_RAND_SEED_NONE)
return rand_pool_entropy_available(pool);
# else
- size_t bytes_needed;
- size_t entropy_available = 0;
- unsigned char *buffer;
+ size_t entropy_available;
# if defined(OPENSSL_RAND_SEED_GETRANDOM)
{
+ size_t bytes_needed;
+ unsigned char *buffer;
ssize_t bytes;
/* Maximum allowed number of consecutive unsuccessful attempts */
int attempts = 3;
# endif
# if defined(OPENSSL_RAND_SEED_DEVRANDOM)
- bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
- {
+ if (wait_random_seeded()) {
+ size_t bytes_needed;
+ unsigned char *buffer;
size_t i;
- for (i = 0; bytes_needed > 0 && i < OSSL_NELEM(random_device_paths); i++) {
+ bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
+ for (i = 0; bytes_needed > 0 && i < OSSL_NELEM(random_device_paths);
+ i++) {
ssize_t bytes = 0;
- /* Maximum allowed number of consecutive unsuccessful attempts */
+ /* Maximum number of consecutive unsuccessful attempts */
int attempts = 3;
const int fd = get_random_device(i);
if (bytes > 0) {
rand_pool_add_end(pool, bytes, 8 * bytes);
bytes_needed -= bytes;
- attempts = 3; /* reset counter after successful attempt */
+ attempts = 3; /* reset counter on successful attempt */
} else if (bytes < 0 && errno != EINTR) {
break;
}
if (bytes < 0 || !keep_random_devices_open)
close_random_device(i);
- bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
+ bytes_needed = rand_pool_bytes_needed(pool, 1);
}
entropy_available = rand_pool_entropy_available(pool);
if (entropy_available > 0)
# endif
# if defined(OPENSSL_RAND_SEED_EGD)
- bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
- if (bytes_needed > 0) {
+ {
static const char *paths[] = { DEVRANDOM_EGD, NULL };
+ size_t bytes_needed;
+ unsigned char *buffer;
int i;
- for (i = 0; paths[i] != NULL; i++) {
+ bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
+ for (i = 0; bytes_needed > 0 && paths[i] != NULL; i++) {
+ size_t bytes = 0;
+ int num;
+
buffer = rand_pool_add_begin(pool, bytes_needed);
- if (buffer != NULL) {
- size_t bytes = 0;
- int num = RAND_query_egd_bytes(paths[i],
- buffer, (int)bytes_needed);
- if (num == (int)bytes_needed)
- bytes = bytes_needed;
+ num = RAND_query_egd_bytes(paths[i],
+ buffer, (int)bytes_needed);
+ if (num == (int)bytes_needed)
+ bytes = bytes_needed;
- rand_pool_add_end(pool, bytes, 8 * bytes);
- entropy_available = rand_pool_entropy_available(pool);
- }
- if (entropy_available > 0)
- return entropy_available;
+ rand_pool_add_end(pool, bytes, 8 * bytes);
+ bytes_needed = rand_pool_bytes_needed(pool, 1);
}
+ entropy_available = rand_pool_entropy_available(pool);
+ if (entropy_available > 0)
+ return entropy_available;
}
# endif
projects / openssl.git / blobdiff