diff --git a/library/entropy_poll.c b/library/entropy_poll.c index 096c02398..b123ac25a 100644 --- a/library/entropy_poll.c +++ b/library/entropy_poll.c @@ -81,6 +81,7 @@ int mbedtls_platform_entropy_poll( void *data, unsigned char *output, size_t len #include #if defined(SYS_getrandom) #define HAVE_GETRANDOM +#include static int getrandom_wrapper( void *buf, size_t buflen, unsigned int flags ) { @@ -90,47 +91,8 @@ static int getrandom_wrapper( void *buf, size_t buflen, unsigned int flags ) memset( buf, 0, buflen ); #endif #endif - return( syscall( SYS_getrandom, buf, buflen, flags ) ); } - -#include -/* Check if version is at least 3.17.0 */ -static int check_version_3_17_plus( void ) -{ - int minor; - struct utsname un; - const char *ver; - - /* Get version information */ - uname(&un); - ver = un.release; - - /* Check major version; assume a single digit */ - if( ver[0] < '3' || ver[0] > '9' || ver [1] != '.' ) - return( -1 ); - - if( ver[0] - '0' > 3 ) - return( 0 ); - - /* Ok, so now we know major == 3, check minor. - * Assume 1 or 2 digits. */ - if( ver[2] < '0' || ver[2] > '9' ) - return( -1 ); - - minor = ver[2] - '0'; - - if( ver[3] >= '0' && ver[3] <= '9' ) - minor = 10 * minor + ver[3] - '0'; - else if( ver [3] != '.' ) - return( -1 ); - - if( minor < 17 ) - return( -1 ); - - return( 0 ); -} -static int has_getrandom = -1; #endif /* SYS_getrandom */ #endif /* __linux__ */ @@ -141,22 +103,21 @@ int mbedtls_platform_entropy_poll( void *data, { FILE *file; size_t read_len; + int ret; ((void) data); #if defined(HAVE_GETRANDOM) - if( has_getrandom == -1 ) - has_getrandom = ( check_version_3_17_plus() == 0 ); - - if( has_getrandom ) + ret = getrandom_wrapper( output, len, 0 ); + if( ret >= 0 ) { - int ret; - - if( ( ret = getrandom_wrapper( output, len, 0 ) ) < 0 ) - return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); - *olen = ret; return( 0 ); } + else if( errno != ENOSYS ) + return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); + /* Fall through if the system call isn't known. */ +#else + ((void) ret; #endif /* HAVE_GETRANDOM */ *olen = 0;