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rand_unix.c: assimilate syscall_random() with getrandom(2) 

Change return value type to ssize_t and ensure that a negative value
is returned only if a corresponding errno is set.

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6990)
This commit is contained in:
Dr. Matthias St. Pierre 2018-08-17 23:29:19 +02:00
parent 8e5da579c1
commit 9b5f1c8fd8
1 changed files with 37 additions and 20 deletions
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57
crypto/rand/rand_unix.c
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@ -77,8 +77,6 @@ static uint64_t get_timer_bits(void);
# endif
#endif /* defined(OPENSSL_SYS_UNIX) || defined(__DJGPP__) */
int syscall_random(void *buf, size_t buflen);
#if (defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_UEFI)) && \
!defined(OPENSSL_RAND_SEED_NONE)
# error "UEFI and VXWorks only support seeding NONE"
@ -88,6 +86,8 @@ int syscall_random(void *buf, size_t buflen);
|| defined(OPENSSL_SYS_VMS) || defined(OPENSSL_SYS_VXWORKS) \
|| defined(OPENSSL_SYS_UEFI))
static ssize_t syscall_random(void *buf, size_t buflen);
# if defined(OPENSSL_SYS_VOS)
# ifndef OPENSSL_RAND_SEED_OS
@ -192,22 +192,29 @@ void rand_pool_keep_random_devices_open(int keep)
# if (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
/*
* sysctl_random(): Use sysctl() to read a random number from the kernel
* Returns the size on success, 0 on failure.
* Returns the number of bytes returned in buf on success, -1 on failure.
*/
static size_t sysctl_random(char *buf, size_t buflen)
static ssize_t sysctl_random(char *buf, size_t buflen)
{
int mib[2];
size_t done = 0;
size_t len;
/*
* Note: sign conversion between size_t and ssize_t is safe even
* without a range check, see comment in syscall_random()
*/
/*
* On FreeBSD old implementations returned longs, newer versions support
* variable sizes up to 256 byte. The code below would not work properly
* when the sysctl returns long and we want to request something not a
* multiple of longs, which should never be the case.
*/
if (!ossl_assert(buflen % sizeof(long) == 0))
return 0;
if (!ossl_assert(buflen % sizeof(long) == 0)) {
errno = EINVAL;
return -1;
}
/*
* On NetBSD before 4.0 KERN_ARND was an alias for KERN_URND, and only
@ -217,7 +224,8 @@ static size_t sysctl_random(char *buf, size_t buflen)
* Just return an error on older NetBSD versions.
*/
#if defined(__NetBSD__) && __NetBSD_Version__ < 400000000
return 0;
errno = ENOSYS;
return -1;
#endif
mib[0] = CTL_KERN;
@ -226,7 +234,7 @@ static size_t sysctl_random(char *buf, size_t buflen)
do {
len = buflen;
if (sysctl(mib, 2, buf, &len, NULL, 0) == -1)
return done;
return done > 0 ? done : -1;
done += len;
buf += len;
buflen -= len;
@ -238,10 +246,20 @@ static size_t sysctl_random(char *buf, size_t buflen)
/*
* syscall_random(): Try to get random data using a system call
* returns the number of bytes returned in buf, or <= 0 on error.
* returns the number of bytes returned in buf, or < 0 on error.
*/
int syscall_random(void *buf, size_t buflen)
static ssize_t syscall_random(void *buf, size_t buflen)
{
/*
* Note: 'buflen' equals the size of the buffer which is used by the
* get_entropy() callback of the RAND_DRBG. It is roughly bounded by
*
* 2 * DRBG_MINMAX_FACTOR * (RAND_DRBG_STRENGTH / 8) = 2^13
*
* which is way below the OSSL_SSIZE_MAX limit. Therefore sign conversion
* between size_t and ssize_t is safe even without a range check.
*/
/*
* Do runtime detection to find getentropy().
*
@ -253,10 +271,10 @@ int syscall_random(void *buf, size_t buflen)
* - FreeBSD since 12.0 (1200061)
*/
# if defined(__GNUC__) && __GNUC__>=2 && defined(__ELF__) && !defined(__hpux)
extern int getentropy(void *bufer, size_t length) __attribute__((weak));
extern int getentropy(void *buffer, size_t length) __attribute__((weak));
if (getentropy != NULL)
return getentropy(buf, buflen) == 0 ? buflen : 0;
return getentropy(buf, buflen) == 0 ? (ssize_t)buflen : -1;
# else
union {
void *p;
@ -271,19 +289,18 @@ int syscall_random(void *buf, size_t buflen)
p_getentropy.p = DSO_global_lookup("getentropy");
ERR_pop_to_mark();
if (p_getentropy.p != NULL)
return p_getentropy.f(buf, buflen) == 0 ? buflen : 0;
return p_getentropy.f(buf, buflen) == 0 ? (ssize_t)buflen : -1;
# endif
/* Linux supports this since version 3.17 */
# if defined(__linux) && defined(SYS_getrandom)
return (int)syscall(SYS_getrandom, buf, buflen, 0);
# endif
# if (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
return (int)sysctl_random(buf, buflen);
# endif
return syscall(SYS_getrandom, buf, buflen, 0);
# elif (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
return sysctl_random(buf, buflen);
# else
errno = ENOSYS;
return -1;
# endif
}
#if !defined(OPENSSL_RAND_SEED_NONE) && defined(OPENSSL_RAND_SEED_DEVRANDOM)