From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- include/crypto/internal/rng.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 include/crypto/internal/rng.h (limited to 'include/crypto/internal/rng.h') diff --git a/include/crypto/internal/rng.h b/include/crypto/internal/rng.h new file mode 100644 index 000000000..e0711b6a5 --- /dev/null +++ b/include/crypto/internal/rng.h @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * RNG: Random Number Generator algorithms under the crypto API + * + * Copyright (c) 2008 Neil Horman + * Copyright (c) 2015 Herbert Xu + */ + +#ifndef _CRYPTO_INTERNAL_RNG_H +#define _CRYPTO_INTERNAL_RNG_H + +#include +#include + +int crypto_register_rng(struct rng_alg *alg); +void crypto_unregister_rng(struct rng_alg *alg); +int crypto_register_rngs(struct rng_alg *algs, int count); +void crypto_unregister_rngs(struct rng_alg *algs, int count); + +#if defined(CONFIG_CRYPTO_RNG) || defined(CONFIG_CRYPTO_RNG_MODULE) +int crypto_del_default_rng(void); +#else +static inline int crypto_del_default_rng(void) +{ + return 0; +} +#endif + +static inline void *crypto_rng_ctx(struct crypto_rng *tfm) +{ + return crypto_tfm_ctx(&tfm->base); +} + +static inline void crypto_rng_set_entropy(struct crypto_rng *tfm, + const u8 *data, unsigned int len) +{ + crypto_rng_alg(tfm)->set_ent(tfm, data, len); +} + +#endif -- cgit v1.3.1