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authorAlexander Potapenko <glider@google.com>2022-09-15 18:04:05 +0300
committerAndrew Morton <akpm@linux-foundation.org>2022-10-04 00:03:23 +0300
commit40b22c9df2c51c6ce459953f57c720b129332fbf (patch)
tree2f4e9f2865d8a4aa94eb2ec5a8f199242828ba0d
parent42eaa27d9e7aafb4049fc3a5b02005a917013e65 (diff)
downloadlinux-40b22c9df2c51c6ce459953f57c720b129332fbf.tar.xz
objtool: kmsan: list KMSAN API functions as uaccess-safe
KMSAN inserts API function calls in a lot of places (function entries and exits, local variables, memory accesses), so they may get called from the uaccess regions as well. KMSAN API functions are used to update the metadata (shadow/origin pages) for kernel memory accesses. The metadata pages for kernel pointers are also located in the kernel memory, so touching them is not a problem. For userspace pointers, no metadata is allocated. If an API function is supposed to read or modify the metadata, it does so for kernel pointers and ignores userspace pointers. If an API function is supposed to return a pair of metadata pointers for the instrumentation to use (like all __msan_metadata_ptr_for_TYPE_SIZE() functions do), it returns the allocated metadata for kernel pointers and special dummy buffers residing in the kernel memory for userspace pointers. As a result, none of KMSAN API functions perform userspace accesses, but since they might be called from UACCESS regions they use user_access_save/restore(). Link: https://lkml.kernel.org/r/20220915150417.722975-32-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--tools/objtool/check.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index e55fdf952a3a..7c048c11ce7d 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1062,6 +1062,26 @@ static const char *uaccess_safe_builtin[] = {
"__sanitizer_cov_trace_cmp4",
"__sanitizer_cov_trace_cmp8",
"__sanitizer_cov_trace_switch",
+ /* KMSAN */
+ "kmsan_copy_to_user",
+ "kmsan_report",
+ "kmsan_unpoison_entry_regs",
+ "kmsan_unpoison_memory",
+ "__msan_chain_origin",
+ "__msan_get_context_state",
+ "__msan_instrument_asm_store",
+ "__msan_metadata_ptr_for_load_1",
+ "__msan_metadata_ptr_for_load_2",
+ "__msan_metadata_ptr_for_load_4",
+ "__msan_metadata_ptr_for_load_8",
+ "__msan_metadata_ptr_for_load_n",
+ "__msan_metadata_ptr_for_store_1",
+ "__msan_metadata_ptr_for_store_2",
+ "__msan_metadata_ptr_for_store_4",
+ "__msan_metadata_ptr_for_store_8",
+ "__msan_metadata_ptr_for_store_n",
+ "__msan_poison_alloca",
+ "__msan_warning",
/* UBSAN */
"ubsan_type_mismatch_common",
"__ubsan_handle_type_mismatch",