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/stat.h | 73 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 include/uapi/asm-generic/stat.h (limited to 'include/uapi/asm-generic/stat.h') diff --git a/include/uapi/asm-generic/stat.h b/include/uapi/asm-generic/stat.h new file mode 100644 index 000000000..0d962ecd1 --- /dev/null +++ b/include/uapi/asm-generic/stat.h @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef __ASM_GENERIC_STAT_H +#define __ASM_GENERIC_STAT_H + +/* + * Everybody gets this wrong and has to stick with it for all + * eternity. Hopefully, this version gets used by new architectures + * so they don't fall into the same traps. + * + * stat64 is copied from powerpc64, with explicit padding added. + * stat is the same structure layout on 64-bit, without the 'long long' + * types. + * + * By convention, 64 bit architectures use the stat interface, while + * 32 bit architectures use the stat64 interface. Note that we don't + * provide an __old_kernel_stat here, which new architecture should + * not have to start with. + */ + +#include + +#define STAT_HAVE_NSEC 1 + +struct stat { + unsigned long st_dev; /* Device. */ + unsigned long st_ino; /* File serial number. */ + unsigned int st_mode; /* File mode. */ + unsigned int st_nlink; /* Link count. */ + unsigned int st_uid; /* User ID of the file's owner. */ + unsigned int st_gid; /* Group ID of the file's group. */ + unsigned long st_rdev; /* Device number, if device. */ + unsigned long __pad1; + long st_size; /* Size of file, in bytes. */ + int st_blksize; /* Optimal block size for I/O. */ + int __pad2; + long st_blocks; /* Number 512-byte blocks allocated. */ + long st_atime; /* Time of last access. */ + unsigned long st_atime_nsec; + long st_mtime; /* Time of last modification. */ + unsigned long st_mtime_nsec; + long st_ctime; /* Time of last status change. */ + unsigned long st_ctime_nsec; + unsigned int __unused4; + unsigned int __unused5; +}; + +/* This matches struct stat64 in glibc2.1. Only used for 32 bit. */ +#if __BITS_PER_LONG != 64 || defined(__ARCH_WANT_STAT64) +struct stat64 { + unsigned long long st_dev; /* Device. */ + unsigned long long st_ino; /* File serial number. */ + unsigned int st_mode; /* File mode. */ + unsigned int st_nlink; /* Link count. */ + unsigned int st_uid; /* User ID of the file's owner. */ + unsigned int st_gid; /* Group ID of the file's group. */ + unsigned long long st_rdev; /* Device number, if device. */ + unsigned long long __pad1; + long long st_size; /* Size of file, in bytes. */ + int st_blksize; /* Optimal block size for I/O. */ + int __pad2; + long long st_blocks; /* Number 512-byte blocks allocated. */ + int st_atime; /* Time of last access. */ + unsigned int st_atime_nsec; + int st_mtime; /* Time of last modification. */ + unsigned int st_mtime_nsec; + int st_ctime; /* Time of last status change. */ + unsigned int st_ctime_nsec; + unsigned int __unused4; + unsigned int __unused5; +}; +#endif + +#endif /* __ASM_GENERIC_STAT_H */ -- cgit v1.3.1