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/jfs/jfs_debug.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 fs/jfs/jfs_debug.c (limited to 'fs/jfs/jfs_debug.c') diff --git a/fs/jfs/jfs_debug.c b/fs/jfs/jfs_debug.c new file mode 100644 index 000000000..44b62b3c3 --- /dev/null +++ b/fs/jfs/jfs_debug.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) International Business Machines Corp., 2000-2004 + * Portions Copyright (C) Christoph Hellwig, 2001-2002 + */ + +#include +#include +#include +#include +#include +#include +#include "jfs_incore.h" +#include "jfs_filsys.h" +#include "jfs_debug.h" + +#ifdef PROC_FS_JFS /* see jfs_debug.h */ + +#ifdef CONFIG_JFS_DEBUG +static int jfs_loglevel_proc_show(struct seq_file *m, void *v) +{ + seq_printf(m, "%d\n", jfsloglevel); + return 0; +} + +static int jfs_loglevel_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, jfs_loglevel_proc_show, NULL); +} + +static ssize_t jfs_loglevel_proc_write(struct file *file, + const char __user *buffer, size_t count, loff_t *ppos) +{ + char c; + + if (get_user(c, buffer)) + return -EFAULT; + + /* yes, I know this is an ASCIIism. --hch */ + if (c < '0' || c > '9') + return -EINVAL; + jfsloglevel = c - '0'; + return count; +} + +static const struct proc_ops jfs_loglevel_proc_ops = { + .proc_open = jfs_loglevel_proc_open, + .proc_read = seq_read, + .proc_lseek = seq_lseek, + .proc_release = single_release, + .proc_write = jfs_loglevel_proc_write, +}; +#endif + +void jfs_proc_init(void) +{ + struct proc_dir_entry *base; + + base = proc_mkdir("fs/jfs", NULL); + if (!base) + return; + +#ifdef CONFIG_JFS_STATISTICS + proc_create_single("lmstats", 0, base, jfs_lmstats_proc_show); + proc_create_single("txstats", 0, base, jfs_txstats_proc_show); + proc_create_single("xtstat", 0, base, jfs_xtstat_proc_show); + proc_create_single("mpstat", 0, base, jfs_mpstat_proc_show); +#endif +#ifdef CONFIG_JFS_DEBUG + proc_create_single("TxAnchor", 0, base, jfs_txanchor_proc_show); + proc_create("loglevel", 0, base, &jfs_loglevel_proc_ops); +#endif +} + +void jfs_proc_clean(void) +{ + remove_proc_subtree("fs/jfs", NULL); +} + +#endif /* PROC_FS_JFS */ -- cgit v1.3.1