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 --- include/uapi/asm-generic/statfs.h | 84 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 include/uapi/asm-generic/statfs.h (limited to 'include/uapi/asm-generic/statfs.h') diff --git a/include/uapi/asm-generic/statfs.h b/include/uapi/asm-generic/statfs.h new file mode 100644 index 000000000..bd35c7619 --- /dev/null +++ b/include/uapi/asm-generic/statfs.h @@ -0,0 +1,84 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _UAPI_GENERIC_STATFS_H +#define _UAPI_GENERIC_STATFS_H + +#include + + +/* + * Most 64-bit platforms use 'long', while most 32-bit platforms use '__u32'. + * Yes, they differ in signedness as well as size. + * Special cases can override it for themselves -- except for S390x, which + * is just a little too special for us. And MIPS, which I'm not touching + * with a 10' pole. + */ +#ifndef __statfs_word +#if __BITS_PER_LONG == 64 +#define __statfs_word __kernel_long_t +#else +#define __statfs_word __u32 +#endif +#endif + +struct statfs { + __statfs_word f_type; + __statfs_word f_bsize; + __statfs_word f_blocks; + __statfs_word f_bfree; + __statfs_word f_bavail; + __statfs_word f_files; + __statfs_word f_ffree; + __kernel_fsid_t f_fsid; + __statfs_word f_namelen; + __statfs_word f_frsize; + __statfs_word f_flags; + __statfs_word f_spare[4]; +}; + +/* + * ARM needs to avoid the 32-bit padding at the end, for consistency + * between EABI and OABI + */ +#ifndef ARCH_PACK_STATFS64 +#define ARCH_PACK_STATFS64 +#endif + +struct statfs64 { + __statfs_word f_type; + __statfs_word f_bsize; + __u64 f_blocks; + __u64 f_bfree; + __u64 f_bavail; + __u64 f_files; + __u64 f_ffree; + __kernel_fsid_t f_fsid; + __statfs_word f_namelen; + __statfs_word f_frsize; + __statfs_word f_flags; + __statfs_word f_spare[4]; +} ARCH_PACK_STATFS64; + +/* + * IA64 and x86_64 need to avoid the 32-bit padding at the end, + * to be compatible with the i386 ABI + */ +#ifndef ARCH_PACK_COMPAT_STATFS64 +#define ARCH_PACK_COMPAT_STATFS64 +#endif + +struct compat_statfs64 { + __u32 f_type; + __u32 f_bsize; + __u64 f_blocks; + __u64 f_bfree; + __u64 f_bavail; + __u64 f_files; + __u64 f_ffree; + __kernel_fsid_t f_fsid; + __u32 f_namelen; + __u32 f_frsize; + __u32 f_flags; + __u32 f_spare[4]; +} ARCH_PACK_COMPAT_STATFS64; + +#endif /* _UAPI_GENERIC_STATFS_H */ -- cgit v1.3.1