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 --- rust/helpers/task.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 rust/helpers/task.c (limited to 'rust/helpers/task.c') diff --git a/rust/helpers/task.c b/rust/helpers/task.c new file mode 100644 index 000000000..c0e1a06ed --- /dev/null +++ b/rust/helpers/task.c @@ -0,0 +1,62 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +__rust_helper void rust_helper_might_resched(void) +{ + might_resched(); +} + +__rust_helper struct task_struct *rust_helper_get_current(void) +{ + return current; +} + +__rust_helper void rust_helper_get_task_struct(struct task_struct *t) +{ + get_task_struct(t); +} + +__rust_helper void rust_helper_put_task_struct(struct task_struct *t) +{ + put_task_struct(t); +} + +__rust_helper kuid_t rust_helper_task_uid(struct task_struct *task) +{ + return task_uid(task); +} + +__rust_helper kuid_t rust_helper_task_euid(struct task_struct *task) +{ + return task_euid(task); +} + +#ifndef CONFIG_USER_NS +__rust_helper uid_t rust_helper_from_kuid(struct user_namespace *to, kuid_t uid) +{ + return from_kuid(to, uid); +} +#endif /* CONFIG_USER_NS */ + +__rust_helper bool rust_helper_uid_eq(kuid_t left, kuid_t right) +{ + return uid_eq(left, right); +} + +__rust_helper kuid_t rust_helper_current_euid(void) +{ + return current_euid(); +} + +__rust_helper struct user_namespace *rust_helper_current_user_ns(void) +{ + return current_user_ns(); +} + +__rust_helper pid_t rust_helper_task_tgid_nr_ns(struct task_struct *tsk, + struct pid_namespace *ns) +{ + return task_tgid_nr_ns(tsk, ns); +} -- cgit v1.3.1