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/demangle-ocaml.c | 68 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 tools/perf/util/demangle-ocaml.c (limited to 'tools/perf/util/demangle-ocaml.c') diff --git a/tools/perf/util/demangle-ocaml.c b/tools/perf/util/demangle-ocaml.c new file mode 100644 index 000000000..9d707bb60 --- /dev/null +++ b/tools/perf/util/demangle-ocaml.c @@ -0,0 +1,68 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include "util/string2.h" + +#include "demangle-ocaml.h" + +#include + +static const char *caml_prefix = "caml"; +static const size_t caml_prefix_len = 4; + +/* mangled OCaml symbols start with "caml" followed by an upper-case letter */ +static bool +ocaml_is_mangled(const char *sym) +{ + return 0 == strncmp(sym, caml_prefix, caml_prefix_len) + && isupper(sym[caml_prefix_len]); +} + +/* + * input: + * sym: a symbol which may have been mangled by the OCaml compiler + * return: + * if the input doesn't look like a mangled OCaml symbol, NULL is returned + * otherwise, a newly allocated string containing the demangled symbol is returned + */ +char * +ocaml_demangle_sym(const char *sym) +{ + char *result; + int j = 0; + int i; + int len; + + if (!ocaml_is_mangled(sym)) { + return NULL; + } + + len = strlen(sym); + + /* the demangled symbol is always smaller than the mangled symbol */ + result = malloc(len + 1); + if (!result) + return NULL; + + /* skip "caml" prefix */ + i = caml_prefix_len; + + while (i < len) { + if (sym[i] == '_' && sym[i + 1] == '_') { + /* "__" -> "." */ + result[j++] = '.'; + i += 2; + } + else if (sym[i] == '$' && isxdigit(sym[i + 1]) && isxdigit(sym[i + 2])) { + /* "$xx" is a hex-encoded character */ + result[j++] = (hex(sym[i + 1]) << 4) | hex(sym[i + 2]); + i += 3; + } + else { + result[j++] = sym[i++]; + } + } + result[j] = '\0'; + + return result; +} -- cgit v1.3.1