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 --- crypto/ecdh_helper.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 crypto/ecdh_helper.c (limited to 'crypto/ecdh_helper.c') diff --git a/crypto/ecdh_helper.c b/crypto/ecdh_helper.c new file mode 100644 index 000000000..f18f9028f --- /dev/null +++ b/crypto/ecdh_helper.c @@ -0,0 +1,83 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2016, Intel Corporation + * Authors: Salvatore Benedetto + */ +#include +#include +#include +#include +#include +#include + +#define ECDH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + sizeof(short)) + +static inline u8 *ecdh_pack_data(void *dst, const void *src, size_t sz) +{ + memcpy(dst, src, sz); + return dst + sz; +} + +static inline const u8 *ecdh_unpack_data(void *dst, const void *src, size_t sz) +{ + memcpy(dst, src, sz); + return src + sz; +} + +unsigned int crypto_ecdh_key_len(const struct ecdh *params) +{ + return ECDH_KPP_SECRET_MIN_SIZE + params->key_size; +} +EXPORT_SYMBOL_GPL(crypto_ecdh_key_len); + +int crypto_ecdh_encode_key(char *buf, unsigned int len, + const struct ecdh *params) +{ + u8 *ptr = buf; + struct kpp_secret secret = { + .type = CRYPTO_KPP_SECRET_TYPE_ECDH, + .len = len + }; + + if (unlikely(!buf)) + return -EINVAL; + + if (len != crypto_ecdh_key_len(params)) + return -EINVAL; + + ptr = ecdh_pack_data(ptr, &secret, sizeof(secret)); + ptr = ecdh_pack_data(ptr, ¶ms->key_size, sizeof(params->key_size)); + ecdh_pack_data(ptr, params->key, params->key_size); + + return 0; +} +EXPORT_SYMBOL_GPL(crypto_ecdh_encode_key); + +int crypto_ecdh_decode_key(const char *buf, unsigned int len, + struct ecdh *params) +{ + const u8 *ptr = buf; + struct kpp_secret secret; + + if (unlikely(!buf || len < ECDH_KPP_SECRET_MIN_SIZE)) + return -EINVAL; + + ptr = ecdh_unpack_data(&secret, ptr, sizeof(secret)); + if (secret.type != CRYPTO_KPP_SECRET_TYPE_ECDH) + return -EINVAL; + + if (unlikely(len < secret.len)) + return -EINVAL; + + ptr = ecdh_unpack_data(¶ms->key_size, ptr, sizeof(params->key_size)); + if (secret.len != crypto_ecdh_key_len(params)) + return -EINVAL; + + /* Don't allocate memory. Set pointer to data + * within the given buffer + */ + params->key = (void *)ptr; + + return 0; +} +EXPORT_SYMBOL_GPL(crypto_ecdh_decode_key); -- cgit v1.3.1