From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60409) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bQAvo-0003IB-3o for qemu-devel@nongnu.org; Thu, 21 Jul 2016 06:10:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bQAvi-0006LN-Qq for qemu-devel@nongnu.org; Thu, 21 Jul 2016 06:10:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55950) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bQAvi-0006LI-KT for qemu-devel@nongnu.org; Thu, 21 Jul 2016 06:10:10 -0400 From: "Daniel P. Berrange" Date: Thu, 21 Jul 2016 11:09:55 +0100 Message-Id: <1469095797-5098-2-git-send-email-berrange@redhat.com> In-Reply-To: <1469095797-5098-1-git-send-email-berrange@redhat.com> References: <1469095797-5098-1-git-send-email-berrange@redhat.com> Subject: [Qemu-devel] [PULL v1 1/3] crypto: use /dev/[u]random as a final fallback random source List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , "Daniel P. Berrange" If neither gcrypt or gnutls are available to provide a cryptographic random number generator, fallback to consuming bytes directly from /dev/[u]random. Signed-off-by: Daniel P. Berrange --- crypto/Makefile.objs | 2 +- crypto/{random-stub.c => random-platform.c} | 37 +++++++++++++++++++++++++++-- 2 files changed, 36 insertions(+), 3 deletions(-) rename crypto/{random-stub.c => random-platform.c} (52%) diff --git a/crypto/Makefile.objs b/crypto/Makefile.objs index 1f86f4f..febffba 100644 --- a/crypto/Makefile.objs +++ b/crypto/Makefile.objs @@ -12,6 +12,7 @@ crypto-obj-y += tlssession.o crypto-obj-y += secret.o crypto-obj-$(CONFIG_GCRYPT) += random-gcrypt.o crypto-obj-$(if $(CONFIG_GCRYPT),n,$(CONFIG_GNUTLS_RND)) += random-gnutls.o +crypto-obj-$(if $(CONFIG_GCRYPT),n,$(if $(CONFIG_GNUTLS_RND),n,y)) += random-platform.o crypto-obj-y += pbkdf.o crypto-obj-$(CONFIG_NETTLE_KDF) += pbkdf-nettle.o crypto-obj-$(if $(CONFIG_NETTLE_KDF),n,$(CONFIG_GCRYPT_KDF)) += pbkdf-gcrypt.o @@ -28,6 +29,5 @@ crypto-obj-y += block-luks.o # Let the userspace emulators avoid linking gnutls/etc crypto-aes-obj-y = aes.o -stub-obj-y += random-stub.o stub-obj-y += pbkdf-stub.o stub-obj-y += hash-stub.o diff --git a/crypto/random-stub.c b/crypto/random-platform.c similarity index 52% rename from crypto/random-stub.c rename to crypto/random-platform.c index 63bbf41..82b755a 100644 --- a/crypto/random-stub.c +++ b/crypto/random-platform.c @@ -26,6 +26,39 @@ int qcrypto_random_bytes(uint8_t *buf G_GNUC_UNUSED, size_t buflen G_GNUC_UNUSED, Error **errp) { - error_setg(errp, "No random byte source provided in this build"); - return -1; + int fd; + int ret = -1; + int got; + + /* TBD perhaps also add support for BSD getentropy / Linux + * getrandom syscalls directly */ + fd = open("/dev/urandom", O_RDONLY); + if (fd == -1 && errno == ENOENT) { + fd = open("/dev/random", O_RDONLY); + } + + if (fd < 0) { + error_setg(errp, "No /dev/urandom or /dev/random found"); + return -1; + } + + while (buflen > 0) { + got = read(fd, buf, buflen); + if (got < 0) { + error_setg_errno(errp, errno, + "Unable to read random bytes"); + goto cleanup; + } else if (!got) { + error_setg(errp, + "Unexpected EOF reading random bytes"); + goto cleanup; + } + buflen -= got; + buf += got; + } + + ret = 0; + cleanup: + close(fd); + return ret; } -- 2.7.4