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 --- scripts/include/hash.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 scripts/include/hash.h (limited to 'scripts/include/hash.h') diff --git a/scripts/include/hash.h b/scripts/include/hash.h new file mode 100644 index 000000000..efa904368 --- /dev/null +++ b/scripts/include/hash.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef HASH_H +#define HASH_H + +static inline unsigned int hash_str(const char *s) +{ + /* fnv32 hash */ + unsigned int hash = 2166136261U; + + for (; *s; s++) + hash = (hash ^ *s) * 0x01000193; + return hash; +} + +/* simplified version of functions from include/linux/hash.h */ +#define GOLDEN_RATIO_32 0x61C88647 + +static inline unsigned int hash_32(unsigned int val) +{ + return 0x61C88647 * val; +} + +static inline unsigned int hash_ptr(const void *ptr) +{ + return hash_32((unsigned int)(unsigned long)ptr); +} + +#endif /* HASH_H */ -- cgit v1.3.1