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 --- tools/perf/util/mutex.c | 125 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 tools/perf/util/mutex.c (limited to 'tools/perf/util/mutex.c') diff --git a/tools/perf/util/mutex.c b/tools/perf/util/mutex.c new file mode 100644 index 000000000..7aa1f3f55 --- /dev/null +++ b/tools/perf/util/mutex.c @@ -0,0 +1,125 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "mutex.h" + +#include "debug.h" +#include +#include + +static void check_err(const char *fn, int err) +{ + char sbuf[STRERR_BUFSIZE]; + + if (err == 0) + return; + + pr_err("%s error: '%s'\n", fn, str_error_r(err, sbuf, sizeof(sbuf))); +} + +#define CHECK_ERR(err) check_err(__func__, err) + +static void __mutex_init(struct mutex *mtx, bool pshared, bool recursive) +{ + pthread_mutexattr_t attr; + + CHECK_ERR(pthread_mutexattr_init(&attr)); + +#ifndef NDEBUG + /* In normal builds enable error checking, such as recursive usage. */ + CHECK_ERR(pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK)); +#endif + if (recursive) + CHECK_ERR(pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE)); + if (pshared) + CHECK_ERR(pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED)); + CHECK_ERR(pthread_mutex_init(&mtx->lock, &attr)); + CHECK_ERR(pthread_mutexattr_destroy(&attr)); +} + +void mutex_init(struct mutex *mtx) +{ + __mutex_init(mtx, /*pshared=*/false, /*recursive=*/false); +} + +void mutex_init_pshared(struct mutex *mtx) +{ + __mutex_init(mtx, /*pshared=*/true, /*recursive=*/false); +} + +void mutex_init_recursive(struct mutex *mtx) +{ + __mutex_init(mtx, /*pshared=*/false, /*recursive=*/true); +} + +void mutex_destroy(struct mutex *mtx) +{ + CHECK_ERR(pthread_mutex_destroy(&mtx->lock)); +} + +void mutex_lock(struct mutex *mtx) + NO_THREAD_SAFETY_ANALYSIS +{ + CHECK_ERR(pthread_mutex_lock(&mtx->lock)); +} + +void mutex_unlock(struct mutex *mtx) + NO_THREAD_SAFETY_ANALYSIS +{ + CHECK_ERR(pthread_mutex_unlock(&mtx->lock)); +} + +bool mutex_trylock(struct mutex *mtx) +{ + int ret = pthread_mutex_trylock(&mtx->lock); + + if (ret == 0) + return true; /* Lock acquired. */ + + if (ret == EBUSY) + return false; /* Lock busy. */ + + /* Print error. */ + CHECK_ERR(ret); + return false; +} + +static void __cond_init(struct cond *cnd, bool pshared) +{ + pthread_condattr_t attr; + + CHECK_ERR(pthread_condattr_init(&attr)); + if (pshared) + CHECK_ERR(pthread_condattr_setpshared(&attr, PTHREAD_PROCESS_SHARED)); + + CHECK_ERR(pthread_cond_init(&cnd->cond, &attr)); + CHECK_ERR(pthread_condattr_destroy(&attr)); +} + +void cond_init(struct cond *cnd) +{ + __cond_init(cnd, /*pshared=*/false); +} + +void cond_init_pshared(struct cond *cnd) +{ + __cond_init(cnd, /*pshared=*/true); +} + +void cond_destroy(struct cond *cnd) +{ + CHECK_ERR(pthread_cond_destroy(&cnd->cond)); +} + +void cond_wait(struct cond *cnd, struct mutex *mtx) +{ + CHECK_ERR(pthread_cond_wait(&cnd->cond, &mtx->lock)); +} + +void cond_signal(struct cond *cnd) +{ + CHECK_ERR(pthread_cond_signal(&cnd->cond)); +} + +void cond_broadcast(struct cond *cnd) +{ + CHECK_ERR(pthread_cond_broadcast(&cnd->cond)); +} -- cgit v1.3.1