linux-stable.git/mm/kmsan, branch linux-6.2.y

mm: kmsan: handle alloc failures in kmsan_vmap_pages_range_noflush()

2023-04-26T12:30:06+00:00

commit 47ebd0310e89c087f56e58c103c44b72a2f6b216 upstream.

As reported by Dipanjan Das, when KMSAN is used together with kernel fault
injection (or, generally, even without the latter), calls to kcalloc() or
__vmap_pages_range_noflush() may fail, leaving the metadata mappings for
the virtual mapping in an inconsistent state.  When these metadata
mappings are accessed later, the kernel crashes.

To address the problem, we return a non-zero error code from
kmsan_vmap_pages_range_noflush() in the case of any allocation/mapping
failure inside it, and make vmap_pages_range_noflush() return an error if
KMSAN fails to allocate the metadata.

This patch also removes KMSAN_WARN_ON() from vmap_pages_range_noflush(),
as these allocation failures are not fatal anymore.

Link: https://lkml.kernel.org/r/20230413131223.4135168-1-glider@google.com
Fixes: b073d7f8aee4 ("mm: kmsan: maintain KMSAN metadata for page operations")
Signed-off-by: Alexander Potapenko 
Reported-by: Dipanjan Das 
  Link: https://lore.kernel.org/linux-mm/CANX2M5ZRrRA64k0hOif02TjmY9kbbO2aCBPyq79es34RXZ=cAw@mail.gmail.com/
Reviewed-by: Marco Elver 
Cc: Christoph Hellwig 
Cc: Dmitry Vyukov 
Cc: Uladzislau Rezki (Sony) 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

mm: kmsan: handle alloc failures in kmsan_ioremap_page_range()

2023-04-26T12:30:06+00:00

commit fdea03e12aa2a44a7bb34144208be97fc25dfd90 upstream.

Similarly to kmsan_vmap_pages_range_noflush(), kmsan_ioremap_page_range()
must also properly handle allocation/mapping failures.  In the case of
such, it must clean up the already created metadata mappings and return an
error code, so that the error can be propagated to ioremap_page_range().
Without doing so, KMSAN may silently fail to bring the metadata for the
page range into a consistent state, which will result in user-visible
crashes when trying to access them.

Link: https://lkml.kernel.org/r/20230413131223.4135168-2-glider@google.com
Fixes: b073d7f8aee4 ("mm: kmsan: maintain KMSAN metadata for page operations")
Signed-off-by: Alexander Potapenko 
Reported-by: Dipanjan Das 
  Link: https://lore.kernel.org/linux-mm/CANX2M5ZRrRA64k0hOif02TjmY9kbbO2aCBPyq79es34RXZ=cAw@mail.gmail.com/
Reviewed-by: Marco Elver 
Cc: Christoph Hellwig 
Cc: Dmitry Vyukov 
Cc: Uladzislau Rezki (Sony) 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

kmsan: export kmsan_handle_urb

2022-12-21T22:31:52+00:00

USB support can be in a loadable module, and this causes a link failure
with KMSAN:

ERROR: modpost: "kmsan_handle_urb" [drivers/usb/core/usbcore.ko] undefined!

Export the symbol so it can be used by this module.

Link: https://lkml.kernel.org/r/20221215162710.3802378-1-arnd@kernel.org
Fixes: 553a80188a5d ("kmsan: handle memory sent to/from USB")
Signed-off-by: Arnd Bergmann 
Reviewed-by: Alexander Potapenko 
Cc: Dmitry Vyukov 
Cc: Marco Elver 
Cc: 
Signed-off-by: Andrew Morton

kmsan: include linux/vmalloc.h

2022-12-21T22:31:51+00:00

This is needed for the vmap/vunmap declarations:

mm/kmsan/kmsan_test.c:316:9: error: implicit declaration of function 'vmap' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
        vbuf = vmap(pages, npages, VM_MAP, PAGE_KERNEL);
               ^
mm/kmsan/kmsan_test.c:316:29: error: use of undeclared identifier 'VM_MAP'
        vbuf = vmap(pages, npages, VM_MAP, PAGE_KERNEL);
                                   ^
mm/kmsan/kmsan_test.c:322:3: error: implicit declaration of function 'vunmap' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
                vunmap(vbuf);
                ^

Link: https://lkml.kernel.org/r/20221215163046.4079767-1-arnd@kernel.org
Fixes: 8ed691b02ade ("kmsan: add tests for KMSAN")
Signed-off-by: Arnd Bergmann 
Reviewed-by: Alexander Potapenko 
Cc: Dmitry Vyukov 
Cc: Marco Elver 
Cc: 
Signed-off-by: Andrew Morton

kmsan: fix memcpy tests

2022-12-12T02:12:21+00:00

Recent Clang changes may cause it to delete calls of memcpy(), if the
source is an uninitialized volatile local.  This happens because passing a
pointer to a volatile local into memcpy() discards the volatile qualifier,
giving the compiler a free hand to optimize the memcpy() call away.

Use OPTIMIZER_HIDE_VAR() to hide the uninitialized var from the too-smart
compiler.

Link: https://lkml.kernel.org/r/20221205145740.694038-1-glider@google.com
Signed-off-by: Alexander Potapenko 
Suggested-by: Marco Elver 
Reviewed-by: Marco Elver 
Cc: Dmitry Vyukov 
Signed-off-by: Andrew Morton

kmsan: allow using __msan_instrument_asm_store() inside runtime

2022-12-12T02:12:11+00:00

In certain cases (e.g.  when handling a softirq)
__msan_instrument_asm_store(&var, sizeof(var)) may be called with from
within KMSAN runtime, but later the value of @var is used with
!kmsan_in_runtime(), leading to false positives.

Because kmsan_internal_unpoison_memory() doesn't take locks, it should be
fine to call it without kmsan_in_runtime() checks, which fixes the
mentioned false positives.

Link: https://lkml.kernel.org/r/20221128094541.2645890-2-glider@google.com
Signed-off-by: Alexander Potapenko 
Cc: Dmitry Vyukov 
Cc: Eric Biggers 
Cc: Ingo Molnar 
Cc: Marco Elver 
Cc: Peter Zijlstra 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

kmsan: core: kmsan_in_runtime() should return true in NMI context

2022-11-08T23:57:24+00:00

Without that, every call to __msan_poison_alloca() in NMI may end up
allocating memory, which is NMI-unsafe.

Link: https://lkml.kernel.org/r/20221102110611.1085175-1-glider@google.com
Link: https://lore.kernel.org/lkml/20221025221755.3810809-1-glider@google.com/
Signed-off-by: Alexander Potapenko 
Acked-by: Peter Zijlstra (Intel) 
Cc: Dmitry Vyukov 
Cc: Marco Elver 
Cc: Borislav Petkov 
Cc: Dave Hansen 
Cc: Ingo Molnar 
Cc: Kees Cook 
Cc: Masahiro Yamada 
Cc: Nick Desaulniers 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton

x86: fortify: kmsan: fix KMSAN fortify builds

2022-10-28T20:37:23+00:00

Ensure that KMSAN builds replace memset/memcpy/memmove calls with the
respective __msan_XXX functions, and that none of the macros are redefined
twice.  This should allow building kernel with both CONFIG_KMSAN and
CONFIG_FORTIFY_SOURCE.

Link: https://lkml.kernel.org/r/20221024212144.2852069-5-glider@google.com
Link: https://github.com/google/kmsan/issues/89
Signed-off-by: Alexander Potapenko 
Reported-by: Tamas K Lengyel 
Cc: Nathan Chancellor 
Cc: Nick Desaulniers 
Cc: Kees Cook 
Signed-off-by: Andrew Morton

mm: kmsan: export kmsan_copy_page_meta()

2022-10-28T20:37:22+00:00

Certain modules call copy_user_highpage(), which calls
kmsan_copy_page_meta() under KMSAN, so we need to export the latter.

Link: https://lkml.kernel.org/r/20221024212144.2852069-1-glider@google.com
Link: https://github.com/google/kmsan/issues/89
Fixes: b073d7f8aee4 ("mm: kmsan: maintain KMSAN metadata for page operations")
Signed-off-by: Alexander Potapenko 
Signed-off-by: Andrew Morton

x86: kmsan: handle CPU entry area

2022-10-03T21:03:26+00:00

Among other data, CPU entry area holds exception stacks, so addresses from
this area can be passed to kmsan_get_metadata().

This previously led to kmsan_get_metadata() returning NULL, which in turn
resulted in a warning that triggered further attempts to call
kmsan_get_metadata() in the exception context, which quickly exhausted the
exception stack.

This patch allocates shadow and origin for the CPU entry area on x86 and
introduces arch_kmsan_get_meta_or_null(), which performs arch-specific
metadata mapping.

Link: https://lkml.kernel.org/r/20220928123219.1101883-1-glider@google.com
Signed-off-by: Alexander Potapenko 
Fixes: 21d723a7c1409 ("kmsan: add KMSAN runtime core")
Cc: Alexander Viro 
Cc: Alexei Starovoitov 
Cc: Andrey Konovalov 
Cc: Andrey Konovalov 
Cc: Andy Lutomirski 
Cc: Arnd Bergmann 
Cc: Borislav Petkov 
Cc: Christoph Hellwig 
Cc: Christoph Lameter 
Cc: David Rientjes 
Cc: Dmitry Vyukov 
Cc: Eric Biggers 
Cc: Eric Biggers 
Cc: Eric Dumazet 
Cc: Greg Kroah-Hartman 
Cc: Herbert Xu 
Cc: Ilya Leoshkevich 
Cc: Ingo Molnar 
Cc: Jens Axboe 
Cc: Joonsoo Kim 
Cc: Kees Cook 
Cc: Marco Elver 
Cc: Mark Rutland 
Cc: Matthew Wilcox 
Cc: Michael S. Tsirkin 
Cc: Pekka Enberg 
Cc: Peter Zijlstra 
Cc: Petr Mladek 
Cc: Stephen Rothwell 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Vasily Gorbik 
Cc: Vegard Nossum 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton