kernel/linux.git/lib, branch v5.8.18

x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()

2020-11-01T11:45:37+00:00

commit ec6347bb43395cb92126788a1a5b25302543f815 upstream. In reaction to a proposal to introduce a memcpy_mcsafe_fast() implementation Linus points out that memcpy_mcsafe() is poorly named relative to communicating the scope of the interface. Specifically what addresses are valid to pass as source, destination, and what faults / exceptions are handled. Of particular concern is that even though x86 might be able to handle the semantics of copy_mc_to_user() with its common copy_user_generic() implementation other archs likely need / want an explicit path for this case: On Fri, May 1, 2020 at 11:28 AM Linus Torvalds wrote: > > On Thu, Apr 30, 2020 at 6:21 PM Dan Williams wrote: > > > > However now I see that copy_user_generic() works for the wrong reason. > > It works because the exception on the source address due to poison > > looks no different than a write fault on the user address to the > > caller, it's still just a short copy. So it makes copy_to_user() work > > for the wrong reason relative to the name. > > Right. > > And it won't work that way on other architectures. On x86, we have a > generic function that can take faults on either side, and we use it > for both cases (and for the "in_user" case too), but that's an > artifact of the architecture oddity. > > In fact, it's probably wrong even on x86 - because it can hide bugs - > but writing those things is painful enough that everybody prefers > having just one function. Replace a single top-level memcpy_mcsafe() with either copy_mc_to_user(), or copy_mc_to_kernel(). Introduce an x86 copy_mc_fragile() name as the rename for the low-level x86 implementation formerly named memcpy_mcsafe(). It is used as the slow / careful backend that is supplanted by a fast copy_mc_generic() in a follow-on patch. One side-effect of this reorganization is that separating copy_mc_64.S to its own file means that perf no longer needs to track dependencies for its memcpy_64.S benchmarks. [ bp: Massage a bit. ] Signed-off-by: Dan Williams Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Acked-by: Michael Ellerman Cc: Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Greg Kroah-Hartman

lib/crc32.c: fix trivial typo in preprocessor condition

2020-10-29T09:08:03+00:00

[ Upstream commit 904542dc56524f921a6bab0639ff6249c01e775f ] Whether crc32_be needs a lookup table is chosen based on CRC_LE_BITS. Obviously, the _be function should be governed by the _BE_ define. This probably never pops up as it's hard to come up with a configuration where CRC_BE_BITS isn't the same as CRC_LE_BITS and as nobody is using bitwise CRC anyway. Fixes: 46c5801eaf86 ("crc32: bolt on crc32c") Signed-off-by: Tobias Jordan Signed-off-by: Andrew Morton Cc: Krzysztof Kozlowski Cc: Jonathan Corbet Cc: Mauro Carvalho Chehab Link: https://lkml.kernel.org/r/20200923182122.GA3338@agrajag.zerfleddert.de Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

ida: Free allocated bitmap in error path

2020-10-29T09:07:53+00:00

[ Upstream commit a219b856a2b993da234108307be772448f22b0ce ] If a bitmap needs to be allocated, and then by the time the thread is scheduled to be run again all the indices which would satisfy the allocation have been allocated then we would leak the allocation. Almost impossible to hit in practice, but a trivial fix. Found by Coverity. Fixes: f32f004cddf8 ("ida: Convert to XArray") Reported-by: coverity-bot Reviewed-by: Kees Cook Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Sasha Levin

Fonts: Support FONT_EXTRA_WORDS macros for built-in fonts

2020-10-14T09:55:45+00:00

commit 6735b4632def0640dbdf4eb9f99816aca18c4f16 upstream. syzbot has reported an issue in the framebuffer layer, where a malicious user may overflow our built-in font data buffers. In order to perform a reliable range check, subsystems need to know `FONTDATAMAX` for each built-in font. Unfortunately, our font descriptor, `struct console_font` does not contain `FONTDATAMAX`, and is part of the UAPI, making it infeasible to modify it. For user-provided fonts, the framebuffer layer resolves this issue by reserving four extra words at the beginning of data buffers. Later, whenever a function needs to access them, it simply uses the following macros: Recently we have gathered all the above macros to . Let us do the same thing for built-in fonts, prepend four extra words (including `FONTDATAMAX`) to their data buffers, so that subsystems can use these macros for all fonts, no matter built-in or user-provided. This patch depends on patch "fbdev, newport_con: Move FONT_EXTRA_WORDS macros into linux/font.h". Cc: stable@vger.kernel.org Link: https://syzkaller.appspot.com/bug?id=08b8be45afea11888776f897895aef9ad1c3ecfd Signed-off-by: Peilin Ye Reviewed-by: Greg Kroah-Hartman Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/ef18af00c35fb3cc826048a5f70924ed6ddce95b.1600953813.git.yepeilin.cs@gmail.com Signed-off-by: Greg Kroah-Hartman

random32: Restore __latent_entropy attribute on net_rand_state

2020-10-07T06:02:54+00:00

[ Upstream commit 09a6b0bc3be793ca8cba580b7992d73e9f68f15d ] Commit f227e3ec3b5c ("random32: update the net random state on interrupt and activity") broke compilation and was temporarily fixed by Linus in 83bdc7275e62 ("random32: remove net_rand_state from the latent entropy gcc plugin") by entirely moving net_rand_state out of the things handled by the latent_entropy GCC plugin. From what I understand when reading the plugin code, using the __latent_entropy attribute on a declaration was the wrong part and simply keeping the __latent_entropy attribute on the variable definition was the correct fix. Fixes: 83bdc7275e62 ("random32: remove net_rand_state from the latent entropy gcc plugin") Acked-by: Willy Tarreau Cc: Emese Revfy Signed-off-by: Thibaut Sautereau Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

lib/bootconfig: Fix to remove tailing spaces after value

2020-10-01T15:36:33+00:00

commit c7af4ecdffe1537ba8aeed0ac12c3326f908df43 upstream. Fix to remove tailing spaces after value. If there is a space after value, the bootconfig failed to remove it because it applies strim() before replacing the delimiter with null. For example, foo = var # comment was parsed as below. foo="var " but user will expect foo="var" This fixes it by applying strim() after removing the delimiter. Link: https://lkml.kernel.org/r/160068149134.1088739.8868306567670058853.stgit@devnote2 Fixes: 76db5a27a827 ("bootconfig: Add Extra Boot Config support") Cc: Ingo Molnar Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

lib/bootconfig: Fix a bug of breaking existing tree nodes

2020-10-01T15:36:33+00:00

commit ead1e19ad905b97261f0ad7a98bb64abb9323b2b upstream. Fix a bug of breaking existing tree nodes by parsing the second and subsequent braces. Since the bootconfig parser uses the node.next field as a flag of current parent node, but this will break the existing tree if the same key node is specified again in the bootconfig. For example, the following bootconfig should be foo.buz and bar. foo bar foo { buz } However, when parsing the brace "{", it breaks foo->bar link by marking open-brace node. So the bootconfig unlinks bar from the bootconfig internal tree. This introduces a stack outside of the tree and record the last open-brace on the stack instead of using node.next field. Link: https://lkml.kernel.org/r/160068148267.1088739.8264704338030168660.stgit@devnote2 Fixes: 76db5a27a827 ("bootconfig: Add Extra Boot Config support") Cc: Ingo Molnar Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

lib/string.c: implement stpcpy

2020-10-01T15:36:33+00:00

commit 1e1b6d63d6340764e00356873e5794225a2a03ea upstream. LLVM implemented a recent "libcall optimization" that lowers calls to `sprintf(dest, "%s", str)` where the return value is used to `stpcpy(dest, str) - dest`. This generally avoids the machinery involved in parsing format strings. `stpcpy` is just like `strcpy` except it returns the pointer to the new tail of `dest`. This optimization was introduced into clang-12. Implement this so that we don't observe linkage failures due to missing symbol definitions for `stpcpy`. Similar to last year's fire drill with: commit 5f074f3e192f ("lib/string.c: implement a basic bcmp") The kernel is somewhere between a "freestanding" environment (no full libc) and "hosted" environment (many symbols from libc exist with the same type, function signature, and semantics). As Peter Anvin notes, there's not really a great way to inform the compiler that you're targeting a freestanding environment but would like to opt-in to some libcall optimizations (see pr/47280 below), rather than opt-out. Arvind notes, -fno-builtin-* behaves slightly differently between GCC and Clang, and Clang is missing many __builtin_* definitions, which I consider a bug in Clang and am working on fixing. Masahiro summarizes the subtle distinction between compilers justly: To prevent transformation from foo() into bar(), there are two ways in Clang to do that; -fno-builtin-foo, and -fno-builtin-bar. There is only one in GCC; -fno-buitin-foo. (Any difference in that behavior in Clang is likely a bug from a missing __builtin_* definition.) Masahiro also notes: We want to disable optimization from foo() to bar(), but we may still benefit from the optimization from foo() into something else. If GCC implements the same transform, we would run into a problem because it is not -fno-builtin-bar, but -fno-builtin-foo that disables that optimization. In this regard, -fno-builtin-foo would be more future-proof than -fno-built-bar, but -fno-builtin-foo is still potentially overkill. We may want to prevent calls from foo() being optimized into calls to bar(), but we still may want other optimization on calls to foo(). It seems that compilers today don't quite provide the fine grain control over which libcall optimizations pseudo-freestanding environments would prefer. Finally, Kees notes that this interface is unsafe, so we should not encourage its use. As such, I've removed the declaration from any header, but it still needs to be exported to avoid linkage errors in modules. Reported-by: Sami Tolvanen Suggested-by: Andy Lavr Suggested-by: Arvind Sankar Suggested-by: Joe Perches Suggested-by: Kees Cook Suggested-by: Masahiro Yamada Suggested-by: Rasmus Villemoes Signed-off-by: Nick Desaulniers Signed-off-by: Andrew Morton Tested-by: Nathan Chancellor Cc: Link: https://lkml.kernel.org/r/20200914161643.938408-1-ndesaulniers@google.com Link: https://bugs.llvm.org/show_bug.cgi?id=47162 Link: https://bugs.llvm.org/show_bug.cgi?id=47280 Link: https://github.com/ClangBuiltLinux/linux/issues/1126 Link: https://man7.org/linux/man-pages/man3/stpcpy.3.html Link: https://pubs.opengroup.org/onlinepubs/9699919799/functions/stpcpy.html Link: https://reviews.llvm.org/D85963 Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

test_firmware: Test platform fw loading on non-EFI systems

2020-09-17T11:55:45+00:00

commit baaabecfc80fad255f866563b53b8c7a3eec176e upstream. On non-EFI systems, it wasn't possible to test the platform firmware loader because it will have never set "checked_fw" during __init. Instead, allow the test code to override this check. Additionally split the declarations into a private symbol namespace so there is greater enforcement of the symbol visibility. Fixes: 548193cba2a7 ("test_firmware: add support for firmware_request_platform") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Acked-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20200909225354.3118328-1-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman

kobject: Restore old behaviour of kobject_del(NULL)

2020-09-17T11:55:41+00:00

commit 40b8b826a6998639dd1c26f0e127f18371e1058d upstream. The commit 079ad2fb4bf9 ("kobject: Avoid premature parent object freeing in kobject_cleanup()") inadvertently dropped a possibility to call kobject_del() with NULL pointer. Restore the old behaviour. Fixes: 079ad2fb4bf9 ("kobject: Avoid premature parent object freeing in kobject_cleanup()") Cc: stable Reported-by: Qu Wenruo Cc: Heikki Krogerus Signed-off-by: Andy Shevchenko Reviewed-by: Qu Wenruo Link: https://lore.kernel.org/r/20200803082706.65347-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman