From 74a6f97b7ae3efec010148ed990880400c27c722 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Thu, 28 Feb 2019 23:37:24 +0100 Subject: wg: genkey: account for short reads of /dev/urandom Apparently Haiku has a misbehaving /dev/urandom. While we're at it, simplify the function signature to completely succeed or completely fail and make sure the caller checks the result. Reported-by: Alexander von Gluck IV Nitpicked-by: Aaron Jones Signed-off-by: Jason A. Donenfeld --- contrib/embeddable-wg-library/wireguard.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) (limited to 'contrib') diff --git a/contrib/embeddable-wg-library/wireguard.c b/contrib/embeddable-wg-library/wireguard.c index 51da8ec..54b8700 100644 --- a/contrib/embeddable-wg-library/wireguard.c +++ b/contrib/embeddable-wg-library/wireguard.c @@ -1751,16 +1751,21 @@ void wg_generate_private_key(wg_key private_key) void wg_generate_preshared_key(wg_key preshared_key) { ssize_t ret; + size_t i; int fd; - -#if defined(__NR_getrandom) - ret = syscall(__NR_getrandom, preshared_key, sizeof(wg_key), 0); - if (ret == sizeof(wg_key)) +#if defined(__OpenBSD__) || (defined(__APPLE__) && MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_12) || (defined(__GLIBC__) && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 25))) + if (!getentropy(preshared_key, sizeof(wg_key))) + return; +#endif +#if defined(__NR_getrandom) && defined(__linux__) + if (syscall(__NR_getrandom, preshared_key, sizeof(wg_key), 0) == sizeof(wg_key)) return; #endif fd = open("/dev/urandom", O_RDONLY); assert(fd >= 0); - ret = read(fd, preshared_key, sizeof(wg_key)); + for (i = 0; i < sizeof(wg_key); i += ret) { + ret = read(fd, preshared_key + i, sizeof(wg_key) - i); + assert(ret > 0); + } close(fd); - assert(ret == sizeof(wg_key)); } -- cgit v1.2.3-59-g8ed1b