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/cipher.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 crypto/cipher.c (limited to 'crypto/cipher.c') diff --git a/crypto/cipher.c b/crypto/cipher.c new file mode 100644 index 000000000..c9dab656a --- /dev/null +++ b/crypto/cipher.c @@ -0,0 +1,91 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Cryptographic API. + * + * Single-block cipher operations. + * + * Copyright (c) 2002 James Morris + * Copyright (c) 2005 Herbert Xu + */ + +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +static int setkey_unaligned(struct crypto_cipher *tfm, const u8 *key, + unsigned int keylen) +{ + struct cipher_alg *cia = crypto_cipher_alg(tfm); + unsigned long alignmask = crypto_cipher_alignmask(tfm); + int ret; + u8 *buffer, *alignbuffer; + unsigned long absize; + + absize = keylen + alignmask; + buffer = kmalloc(absize, GFP_ATOMIC); + if (!buffer) + return -ENOMEM; + + alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); + memcpy(alignbuffer, key, keylen); + ret = cia->cia_setkey(crypto_cipher_tfm(tfm), alignbuffer, keylen); + kfree_sensitive(buffer); + return ret; + +} + +int crypto_cipher_setkey(struct crypto_cipher *tfm, + const u8 *key, unsigned int keylen) +{ + struct cipher_alg *cia = crypto_cipher_alg(tfm); + unsigned long alignmask = crypto_cipher_alignmask(tfm); + + if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) + return -EINVAL; + + if ((unsigned long)key & alignmask) + return setkey_unaligned(tfm, key, keylen); + + return cia->cia_setkey(crypto_cipher_tfm(tfm), key, keylen); +} +EXPORT_SYMBOL_NS_GPL(crypto_cipher_setkey, "CRYPTO_INTERNAL"); + +static inline void cipher_crypt_one(struct crypto_cipher *tfm, + u8 *dst, const u8 *src, bool enc) +{ + unsigned long alignmask = crypto_cipher_alignmask(tfm); + struct cipher_alg *cia = crypto_cipher_alg(tfm); + void (*fn)(struct crypto_tfm *, u8 *, const u8 *) = + enc ? cia->cia_encrypt : cia->cia_decrypt; + + if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) { + unsigned int bs = crypto_cipher_blocksize(tfm); + u8 buffer[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK]; + u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); + + memcpy(tmp, src, bs); + fn(crypto_cipher_tfm(tfm), tmp, tmp); + memcpy(dst, tmp, bs); + } else { + fn(crypto_cipher_tfm(tfm), dst, src); + } +} + +void crypto_cipher_encrypt_one(struct crypto_cipher *tfm, + u8 *dst, const u8 *src) +{ + cipher_crypt_one(tfm, dst, src, true); +} +EXPORT_SYMBOL_NS_GPL(crypto_cipher_encrypt_one, "CRYPTO_INTERNAL"); + +void crypto_cipher_decrypt_one(struct crypto_cipher *tfm, + u8 *dst, const u8 *src) +{ + cipher_crypt_one(tfm, dst, src, false); +} +EXPORT_SYMBOL_NS_GPL(crypto_cipher_decrypt_one, "CRYPTO_INTERNAL"); -- cgit v1.3.1