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 --- Documentation/ABI/testing/procfs-attr-exec | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) create mode 100644 Documentation/ABI/testing/procfs-attr-exec (limited to 'Documentation/ABI/testing/procfs-attr-exec') diff --git a/Documentation/ABI/testing/procfs-attr-exec b/Documentation/ABI/testing/procfs-attr-exec new file mode 100644 index 000000000..34593866a --- /dev/null +++ b/Documentation/ABI/testing/procfs-attr-exec @@ -0,0 +1,20 @@ +What: /proc/*/attr/exec +Contact: linux-security-module@vger.kernel.org, + selinux@vger.kernel.org, + apparmor@lists.ubuntu.com +Description: The security information to be used on the process + by a Linux security module (LSM) active on the system + after a subsequent exec() call. + The details of permissions required to read from + this interface and hence obtain the security state + of the task identified is LSM dependent. + A process cannot write to this interface unless it + refers to itself. + The other details of permissions required to write to + this interface and hence change the security state of + the task identified are LSM dependent. + The format of the data used by this interface is LSM + dependent. + SELinux and AppArmor provide this interface. +Users: SELinux user-space + AppArmor user-space -- cgit v1.3.1