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 --- fs/adfs/dir_fplus.h | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 fs/adfs/dir_fplus.h (limited to 'fs/adfs/dir_fplus.h') diff --git a/fs/adfs/dir_fplus.h b/fs/adfs/dir_fplus.h new file mode 100644 index 000000000..d729b1591 --- /dev/null +++ b/fs/adfs/dir_fplus.h @@ -0,0 +1,42 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * linux/fs/adfs/dir_fplus.h + * + * Copyright (C) 1999 Russell King + * + * Structures of directories on the F+ format disk + */ + +#define ADFS_FPLUS_NAME_LEN 255 + +#define BIGDIRSTARTNAME ('S' | 'B' << 8 | 'P' << 16 | 'r' << 24) +#define BIGDIRENDNAME ('o' | 'v' << 8 | 'e' << 16 | 'n' << 24) + +struct adfs_bigdirheader { + __u8 startmasseq; + __u8 bigdirversion[3]; + __le32 bigdirstartname; + __le32 bigdirnamelen; + __le32 bigdirsize; + __le32 bigdirentries; + __le32 bigdirnamesize; + __le32 bigdirparent; + char bigdirname[1]; +} __attribute__((packed, aligned(4))); + +struct adfs_bigdirentry { + __le32 bigdirload; + __le32 bigdirexec; + __le32 bigdirlen; + __le32 bigdirindaddr; + __le32 bigdirattr; + __le32 bigdirobnamelen; + __le32 bigdirobnameptr; +} __attribute__((packed, aligned(4))); + +struct adfs_bigdirtail { + __le32 bigdirendname; + __u8 bigdirendmasseq; + __u8 reserved[2]; + __u8 bigdircheckbyte; +} __attribute__((packed, aligned(4))); -- cgit v1.3.1