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/lz4.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 crypto/lz4.c (limited to 'crypto/lz4.c') diff --git a/crypto/lz4.c b/crypto/lz4.c new file mode 100644 index 000000000..57b713516 --- /dev/null +++ b/crypto/lz4.c @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Cryptographic API. + * + * Copyright (c) 2013 Chanho Min + */ + +#include +#include +#include +#include +#include +#include + +static void *lz4_alloc_ctx(void) +{ + void *ctx; + + ctx = vmalloc(LZ4_MEM_COMPRESS); + if (!ctx) + return ERR_PTR(-ENOMEM); + + return ctx; +} + +static void lz4_free_ctx(void *ctx) +{ + vfree(ctx); +} + +static int __lz4_compress_crypto(const u8 *src, unsigned int slen, + u8 *dst, unsigned int *dlen, void *ctx) +{ + int out_len = LZ4_compress_default(src, dst, + slen, *dlen, ctx); + + if (!out_len) + return -EINVAL; + + *dlen = out_len; + return 0; +} + +static int lz4_scompress(struct crypto_scomp *tfm, const u8 *src, + unsigned int slen, u8 *dst, unsigned int *dlen, + void *ctx) +{ + return __lz4_compress_crypto(src, slen, dst, dlen, ctx); +} + +static int __lz4_decompress_crypto(const u8 *src, unsigned int slen, + u8 *dst, unsigned int *dlen, void *ctx) +{ + int out_len = LZ4_decompress_safe(src, dst, slen, *dlen); + + if (out_len < 0) + return -EINVAL; + + *dlen = out_len; + return 0; +} + +static int lz4_sdecompress(struct crypto_scomp *tfm, const u8 *src, + unsigned int slen, u8 *dst, unsigned int *dlen, + void *ctx) +{ + return __lz4_decompress_crypto(src, slen, dst, dlen, NULL); +} + +static struct scomp_alg scomp = { + .streams = { + .alloc_ctx = lz4_alloc_ctx, + .free_ctx = lz4_free_ctx, + }, + .compress = lz4_scompress, + .decompress = lz4_sdecompress, + .base = { + .cra_name = "lz4", + .cra_driver_name = "lz4-scomp", + .cra_module = THIS_MODULE, + } +}; + +static int __init lz4_mod_init(void) +{ + return crypto_register_scomp(&scomp); +} + +static void __exit lz4_mod_fini(void) +{ + crypto_unregister_scomp(&scomp); +} + +module_init(lz4_mod_init); +module_exit(lz4_mod_fini); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("LZ4 Compression Algorithm"); +MODULE_ALIAS_CRYPTO("lz4"); -- cgit v1.3.1