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 --- drivers/md/dm-vdo/numeric.h | 78 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 drivers/md/dm-vdo/numeric.h (limited to 'drivers/md/dm-vdo/numeric.h') diff --git a/drivers/md/dm-vdo/numeric.h b/drivers/md/dm-vdo/numeric.h new file mode 100644 index 000000000..f568dc59e --- /dev/null +++ b/drivers/md/dm-vdo/numeric.h @@ -0,0 +1,78 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright 2023 Red Hat + */ + +#ifndef UDS_NUMERIC_H +#define UDS_NUMERIC_H + +#include +#include +#include + +/* + * These utilities encode or decode a number from an offset in a larger data buffer and then + * advance the offset pointer to the next field in the buffer. + */ + +static inline void decode_s64_le(const u8 *buffer, size_t *offset, s64 *decoded) +{ + *decoded = get_unaligned_le64(buffer + *offset); + *offset += sizeof(s64); +} + +static inline void encode_s64_le(u8 *data, size_t *offset, s64 to_encode) +{ + put_unaligned_le64(to_encode, data + *offset); + *offset += sizeof(s64); +} + +static inline void decode_u64_le(const u8 *buffer, size_t *offset, u64 *decoded) +{ + *decoded = get_unaligned_le64(buffer + *offset); + *offset += sizeof(u64); +} + +static inline void encode_u64_le(u8 *data, size_t *offset, u64 to_encode) +{ + put_unaligned_le64(to_encode, data + *offset); + *offset += sizeof(u64); +} + +static inline void decode_s32_le(const u8 *buffer, size_t *offset, s32 *decoded) +{ + *decoded = get_unaligned_le32(buffer + *offset); + *offset += sizeof(s32); +} + +static inline void encode_s32_le(u8 *data, size_t *offset, s32 to_encode) +{ + put_unaligned_le32(to_encode, data + *offset); + *offset += sizeof(s32); +} + +static inline void decode_u32_le(const u8 *buffer, size_t *offset, u32 *decoded) +{ + *decoded = get_unaligned_le32(buffer + *offset); + *offset += sizeof(u32); +} + +static inline void encode_u32_le(u8 *data, size_t *offset, u32 to_encode) +{ + put_unaligned_le32(to_encode, data + *offset); + *offset += sizeof(u32); +} + +static inline void decode_u16_le(const u8 *buffer, size_t *offset, u16 *decoded) +{ + *decoded = get_unaligned_le16(buffer + *offset); + *offset += sizeof(u16); +} + +static inline void encode_u16_le(u8 *data, size_t *offset, u16 to_encode) +{ + put_unaligned_le16(to_encode, data + *offset); + *offset += sizeof(u16); +} + +#endif /* UDS_NUMERIC_H */ -- cgit v1.3.1