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/path.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 tools/perf/util/path.c (limited to 'tools/perf/util/path.c') diff --git a/tools/perf/util/path.c b/tools/perf/util/path.c new file mode 100644 index 000000000..2e62f272f --- /dev/null +++ b/tools/perf/util/path.c @@ -0,0 +1,79 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "path.h" +#include "cache.h" +#include +#include +#include +#include +#include +#include +#include +#include + +static char *cleanup_path(char *path) +{ + /* Clean it up */ + if (!memcmp(path, "./", 2)) { + path += 2; + while (*path == '/') + path++; + } + return path; +} + +char *mkpath(char *path_buf, size_t sz, const char *fmt, ...) +{ + va_list args; + unsigned len; + + va_start(args, fmt); + len = vsnprintf(path_buf, sz, fmt, args); + va_end(args); + if (len >= sz) + strncpy(path_buf, "/bad-path/", sz); + return cleanup_path(path_buf); +} + +int path__join(char *bf, size_t size, const char *path1, const char *path2) +{ + return scnprintf(bf, size, "%s%s%s", path1, path1[0] ? "/" : "", path2); +} + +int path__join3(char *bf, size_t size, const char *path1, const char *path2, const char *path3) +{ + return scnprintf(bf, size, "%s%s%s%s%s", path1, path1[0] ? "/" : "", + path2, path2[0] ? "/" : "", path3); +} + +bool is_regular_file(const char *file) +{ + struct stat st; + + if (stat(file, &st)) + return false; + + return S_ISREG(st.st_mode); +} + +/* Helper function for filesystems that return a dent->d_type DT_UNKNOWN */ +bool is_directory(const char *base_path, const struct dirent *dent) +{ + char path[PATH_MAX]; + struct stat st; + + snprintf(path, sizeof(path), "%s/%s", base_path, dent->d_name); + if (stat(path, &st)) + return false; + + return S_ISDIR(st.st_mode); +} + +bool is_directory_at(int dir_fd, const char *path) +{ + struct stat st; + + if (fstatat(dir_fd, path, &st, /*flags=*/0)) + return false; + + return S_ISDIR(st.st_mode); +} -- cgit v1.3.1