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/crc32.c | 129 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+) create mode 100644 crypto/crc32.c (limited to 'crypto/crc32.c') diff --git a/crypto/crc32.c b/crypto/crc32.c new file mode 100644 index 000000000..489cbed94 --- /dev/null +++ b/crypto/crc32.c @@ -0,0 +1,129 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2012 Xyratex Technology Limited + */ + +/* + * This is crypto api shash wrappers to crc32_le. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define CHKSUM_BLOCK_SIZE 1 +#define CHKSUM_DIGEST_SIZE 4 + +/** No default init with ~0 */ +static int crc32_cra_init(struct crypto_tfm *tfm) +{ + u32 *key = crypto_tfm_ctx(tfm); + + *key = 0; + + return 0; +} + +/* + * Setting the seed allows arbitrary accumulators and flexible XOR policy + * If your algorithm starts with ~0, then XOR with ~0 before you set + * the seed. + */ +static int crc32_setkey(struct crypto_shash *hash, const u8 *key, + unsigned int keylen) +{ + u32 *mctx = crypto_shash_ctx(hash); + + if (keylen != sizeof(u32)) + return -EINVAL; + *mctx = get_unaligned_le32(key); + return 0; +} + +static int crc32_init(struct shash_desc *desc) +{ + u32 *mctx = crypto_shash_ctx(desc->tfm); + u32 *crcp = shash_desc_ctx(desc); + + *crcp = *mctx; + + return 0; +} + +static int crc32_update(struct shash_desc *desc, const u8 *data, + unsigned int len) +{ + u32 *crcp = shash_desc_ctx(desc); + + *crcp = crc32_le(*crcp, data, len); + return 0; +} + +/* No final XOR 0xFFFFFFFF, like crc32_le */ +static int __crc32_finup(u32 *crcp, const u8 *data, unsigned int len, u8 *out) +{ + put_unaligned_le32(crc32_le(*crcp, data, len), out); + return 0; +} + +static int crc32_finup(struct shash_desc *desc, const u8 *data, + unsigned int len, u8 *out) +{ + return __crc32_finup(shash_desc_ctx(desc), data, len, out); +} + +static int crc32_final(struct shash_desc *desc, u8 *out) +{ + u32 *crcp = shash_desc_ctx(desc); + + put_unaligned_le32(*crcp, out); + return 0; +} + +static int crc32_digest(struct shash_desc *desc, const u8 *data, + unsigned int len, u8 *out) +{ + return __crc32_finup(crypto_shash_ctx(desc->tfm), data, len, out); +} + +static struct shash_alg alg = { + .setkey = crc32_setkey, + .init = crc32_init, + .update = crc32_update, + .final = crc32_final, + .finup = crc32_finup, + .digest = crc32_digest, + .descsize = sizeof(u32), + .digestsize = CHKSUM_DIGEST_SIZE, + + .base.cra_name = "crc32", + .base.cra_driver_name = "crc32-lib", + .base.cra_priority = 100, + .base.cra_flags = CRYPTO_ALG_OPTIONAL_KEY, + .base.cra_blocksize = CHKSUM_BLOCK_SIZE, + .base.cra_ctxsize = sizeof(u32), + .base.cra_module = THIS_MODULE, + .base.cra_init = crc32_cra_init, +}; + +static int __init crc32_mod_init(void) +{ + return crypto_register_shash(&alg); +} + +static void __exit crc32_mod_fini(void) +{ + crypto_unregister_shash(&alg); +} + +module_init(crc32_mod_init); +module_exit(crc32_mod_fini); + +MODULE_AUTHOR("Alexander Boyko "); +MODULE_DESCRIPTION("CRC32 calculations wrapper for lib/crc32"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_CRYPTO("crc32"); -- cgit v1.3.1