From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- crypto/rng.c | 245 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 245 insertions(+) create mode 100644 crypto/rng.c (limited to 'crypto/rng.c') diff --git a/crypto/rng.c b/crypto/rng.c new file mode 100644 index 000000000..828b0d807 --- /dev/null +++ b/crypto/rng.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Cryptographic API. + * + * RNG operations. + * + * Copyright (c) 2008 Neil Horman + * Copyright (c) 2015 Herbert Xu + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "internal.h" + +static DEFINE_MUTEX(crypto_default_rng_lock); +static struct crypto_rng *crypto_default_rng; +static int crypto_default_rng_refcnt; + +int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen) +{ + u8 *buf = NULL; + int err; + + if (!seed && slen) { + buf = kmalloc(slen, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + err = get_random_bytes_wait(buf, slen); + if (err) + goto out; + seed = buf; + } + + err = crypto_rng_alg(tfm)->seed(tfm, seed, slen); +out: + kfree_sensitive(buf); + return err; +} +EXPORT_SYMBOL_GPL(crypto_rng_reset); + +static int crypto_rng_init_tfm(struct crypto_tfm *tfm) +{ + return 0; +} + +static unsigned int seedsize(struct crypto_alg *alg) +{ + struct rng_alg *ralg = container_of(alg, struct rng_alg, base); + + return ralg->seedsize; +} + +static int __maybe_unused crypto_rng_report( + struct sk_buff *skb, struct crypto_alg *alg) +{ + struct crypto_report_rng rrng = { + .type = "rng", + }; + + rrng.seedsize = seedsize(alg); + + return nla_put(skb, CRYPTOCFGA_REPORT_RNG, sizeof(rrng), &rrng); +} + +static void __maybe_unused crypto_rng_show(struct seq_file *m, + struct crypto_alg *alg) +{ + seq_printf(m, "type : rng\n"); + seq_printf(m, "seedsize : %u\n", seedsize(alg)); +} + +static const struct crypto_type crypto_rng_type = { + .extsize = crypto_alg_extsize, + .init_tfm = crypto_rng_init_tfm, +#ifdef CONFIG_PROC_FS + .show = crypto_rng_show, +#endif +#if IS_ENABLED(CONFIG_CRYPTO_USER) + .report = crypto_rng_report, +#endif + .maskclear = ~CRYPTO_ALG_TYPE_MASK, + .maskset = CRYPTO_ALG_TYPE_MASK, + .type = CRYPTO_ALG_TYPE_RNG, + .tfmsize = offsetof(struct crypto_rng, base), + .algsize = offsetof(struct rng_alg, base), +}; + +struct crypto_rng *crypto_alloc_rng(const char *alg_name, u32 type, u32 mask) +{ + return crypto_alloc_tfm(alg_name, &crypto_rng_type, type, mask); +} +EXPORT_SYMBOL_GPL(crypto_alloc_rng); + +static int crypto_get_default_rng(void) +{ + struct crypto_rng *rng; + int err; + + mutex_lock(&crypto_default_rng_lock); + if (!crypto_default_rng) { + rng = crypto_alloc_rng("stdrng", 0, 0); + err = PTR_ERR(rng); + if (IS_ERR(rng)) + goto unlock; + + err = crypto_rng_reset(rng, NULL, crypto_rng_seedsize(rng)); + if (err) { + crypto_free_rng(rng); + goto unlock; + } + + crypto_default_rng = rng; + } + + crypto_default_rng_refcnt++; + err = 0; + +unlock: + mutex_unlock(&crypto_default_rng_lock); + + return err; +} + +static void crypto_put_default_rng(void) +{ + mutex_lock(&crypto_default_rng_lock); + crypto_default_rng_refcnt--; + mutex_unlock(&crypto_default_rng_lock); +} + +int __crypto_stdrng_get_bytes(void *buf, unsigned int len) +{ + int err; + + err = crypto_get_default_rng(); + if (err) + return err; + + err = crypto_rng_get_bytes(crypto_default_rng, buf, len); + crypto_put_default_rng(); + return err; +} +EXPORT_SYMBOL_GPL(__crypto_stdrng_get_bytes); + +#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE) +int crypto_del_default_rng(void) +{ + int err = -EBUSY; + + mutex_lock(&crypto_default_rng_lock); + if (crypto_default_rng_refcnt) + goto out; + + crypto_free_rng(crypto_default_rng); + crypto_default_rng = NULL; + + err = 0; + +out: + mutex_unlock(&crypto_default_rng_lock); + + return err; +} +EXPORT_SYMBOL_GPL(crypto_del_default_rng); +#endif + +static void rng_default_set_ent(struct crypto_rng *tfm, const u8 *data, + unsigned int len) +{ +} + +int crypto_register_rng(struct rng_alg *alg) +{ + struct crypto_alg *base = &alg->base; + + if (alg->seedsize > PAGE_SIZE / 8) + return -EINVAL; + + base->cra_type = &crypto_rng_type; + base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK; + base->cra_flags |= CRYPTO_ALG_TYPE_RNG; + + if (!alg->set_ent) + alg->set_ent = rng_default_set_ent; + + return crypto_register_alg(base); +} +EXPORT_SYMBOL_GPL(crypto_register_rng); + +void crypto_unregister_rng(struct rng_alg *alg) +{ + crypto_unregister_alg(&alg->base); +} +EXPORT_SYMBOL_GPL(crypto_unregister_rng); + +int crypto_register_rngs(struct rng_alg *algs, int count) +{ + int i, ret; + + for (i = 0; i < count; i++) { + ret = crypto_register_rng(algs + i); + if (ret) { + crypto_unregister_rngs(algs, i); + return ret; + } + } + + return 0; +} +EXPORT_SYMBOL_GPL(crypto_register_rngs); + +void crypto_unregister_rngs(struct rng_alg *algs, int count) +{ + int i; + + for (i = count - 1; i >= 0; --i) + crypto_unregister_rng(algs + i); +} +EXPORT_SYMBOL_GPL(crypto_unregister_rngs); + +static void __exit rng_exit(void) +{ + int err; + + err = crypto_del_default_rng(); + if (err) + pr_err("Failed delete default RNG: %d\n", err); +} + +module_exit(rng_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Random Number Generator"); -- cgit v1.3.1