Module Name: src Committed By: riastradh Date: Mon May 11 17:27:48 UTC 2020
Modified Files: src/sys/kern: subr_cprng.c Log Message: Work around early calls to cprng_strong. The bottleneck here is getting percpu_create to work early enough. We should really fix that, but for now, this workaround will serve. Should fix PR port-arm32/55252. To generate a diff of this commit: cvs rdiff -u -r1.37 -r1.38 src/sys/kern/subr_cprng.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.
Modified files: Index: src/sys/kern/subr_cprng.c diff -u src/sys/kern/subr_cprng.c:1.37 src/sys/kern/subr_cprng.c:1.38 --- src/sys/kern/subr_cprng.c:1.37 Thu Apr 30 17:36:06 2020 +++ src/sys/kern/subr_cprng.c Mon May 11 17:27:48 2020 @@ -1,4 +1,4 @@ -/* $NetBSD: subr_cprng.c,v 1.37 2020/04/30 17:36:06 nia Exp $ */ +/* $NetBSD: subr_cprng.c,v 1.38 2020/05/11 17:27:48 riastradh Exp $ */ /*- * Copyright (c) 2019 The NetBSD Foundation, Inc. @@ -52,7 +52,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: subr_cprng.c,v 1.37 2020/04/30 17:36:06 nia Exp $"); +__KERNEL_RCSID(0, "$NetBSD: subr_cprng.c,v 1.38 2020/05/11 17:27:48 riastradh Exp $"); #include <sys/types.h> #include <sys/cprng.h> @@ -102,6 +102,7 @@ struct cprng_strong *kern_cprng __read_m struct cprng_strong *user_cprng __read_mostly; /* IPL_NONE */ static struct sysctllog *cprng_sysctllog __read_mostly; +static bool cprng_initialized __read_mostly = false; void cprng_init(void) @@ -128,6 +129,9 @@ cprng_init(void) CTLFLAG_PERMANENT|CTLFLAG_READONLY, CTLTYPE_INT /*lie*/, "arandom", SYSCTL_DESCR("Independent uniform random bytes, up to 256 bytes"), sysctl_kern_arandom, 0, NULL, 0, CTL_KERN, KERN_ARND, CTL_EOL); + + /* Ready to go. */ + cprng_initialized = true; } /* @@ -274,6 +278,25 @@ cprng_strong(struct cprng_strong *cprng, int s; /* + * Some device drivers try to use cprng_strong in attach during + * autoconf, e.g. to randomly generate MAC addresses, before we + * percpu is available -- percpu is not available until after + * CPUs have been detected during autoconf. We should make + * percpu available sooner, but for now this works around it. + */ + if (__predict_false(!cprng_initialized)) { + struct nist_hash_drbg drbg; + entropy_extract(seed, sizeof seed, 0); + if (__predict_false(nist_hash_drbg_instantiate(&drbg, + seed, sizeof seed, NULL, 0, NULL, 0))) + panic("nist_hash_drbg_instantiate"); + if (__predict_false(nist_hash_drbg_generate(&drbg, buf, len, + NULL, 0))) + panic("nist_hash_drbg_generate"); + return len; + } + + /* * Verify maximum request length. Caller should really limit * their requests to 32 bytes to avoid spending much time with * preemption disabled -- use the 32 bytes to seed a private