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 --- drivers/char/tpm/tpm-dev.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 drivers/char/tpm/tpm-dev.h (limited to 'drivers/char/tpm/tpm-dev.h') diff --git a/drivers/char/tpm/tpm-dev.h b/drivers/char/tpm/tpm-dev.h new file mode 100644 index 000000000..f3742bcc7 --- /dev/null +++ b/drivers/char/tpm/tpm-dev.h @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _TPM_DEV_H +#define _TPM_DEV_H + +#include +#include "tpm.h" + +struct file_priv { + struct tpm_chip *chip; + struct tpm_space *space; + + struct mutex buffer_mutex; + struct timer_list user_read_timer; /* user needs to claim result */ + struct work_struct timeout_work; + struct work_struct async_work; + wait_queue_head_t async_wait; + ssize_t response_length; + bool response_read; + bool command_enqueued; + + u8 data_buffer[TPM_BUFSIZE]; +}; + +void tpm_common_open(struct file *file, struct tpm_chip *chip, + struct file_priv *priv, struct tpm_space *space); +ssize_t tpm_common_read(struct file *file, char __user *buf, + size_t size, loff_t *off); +ssize_t tpm_common_write(struct file *file, const char __user *buf, + size_t size, loff_t *off); +__poll_t tpm_common_poll(struct file *file, poll_table *wait); + +void tpm_common_release(struct file *file, struct file_priv *priv); +#endif -- cgit v1.3.1