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/trace/syscall.h | 57 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 include/trace/syscall.h (limited to 'include/trace/syscall.h') diff --git a/include/trace/syscall.h b/include/trace/syscall.h new file mode 100644 index 000000000..0dd7f2b33 --- /dev/null +++ b/include/trace/syscall.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _TRACE_SYSCALL_H +#define _TRACE_SYSCALL_H + +#include +#include +#include +#include + +#include + + +/* + * A syscall entry in the ftrace syscalls array. + * + * @name: name of the syscall + * @syscall_nr: number of the syscall + * @nb_args: number of parameters it takes + * @user_arg_is_str: set if the arg for @user_arg_size is a string + * @user_arg_size: holds @arg that has size of the user space to read + * @user_mask: mask of @args that will read user space + * @types: list of types as strings + * @args: list of args as strings (args[i] matches types[i]) + * @enter_fields: list of fields for syscall_enter trace event + * @enter_event: associated syscall_enter trace event + * @exit_event: associated syscall_exit trace event + */ +struct syscall_metadata { + const char *name; + int syscall_nr; + u8 nb_args:7; + u8 user_arg_is_str:1; + s8 user_arg_size; + short user_mask; + const char **types; + const char **args; + struct list_head enter_fields; + + struct trace_event_call *enter_event; + struct trace_event_call *exit_event; +}; + +#if defined(CONFIG_TRACEPOINTS) && defined(CONFIG_HAVE_SYSCALL_TRACEPOINTS) +static inline void syscall_tracepoint_update(struct task_struct *p) +{ + if (test_syscall_work(SYSCALL_TRACEPOINT)) + set_task_syscall_work(p, SYSCALL_TRACEPOINT); + else + clear_task_syscall_work(p, SYSCALL_TRACEPOINT); +} +#else +static inline void syscall_tracepoint_update(struct task_struct *p) +{ +} +#endif + +#endif /* _TRACE_SYSCALL_H */ -- cgit v1.3.1