From 3b293487b8752cc42c1cbf8a0447bc6076c075fa Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 12 Jan 2023 15:03:16 -0800 Subject: [PATCH 1/5] firmware: coreboot: Check size of table entry and use flex-array The memcpy() of the data following a coreboot_table_entry couldn't be evaluated by the compiler under CONFIG_FORTIFY_SOURCE. To make it easier to reason about, add an explicit flexible array member to struct coreboot_device so the entire entry can be copied at once. Additionally, validate the sizes before copying. Avoids this run-time false positive warning: memcpy: detected field-spanning write (size 168) of single field "&device->entry" at drivers/firmware/google/coreboot_table.c:103 (size 8) Reported-by: Paul Menzel Link: https://lore.kernel.org/all/03ae2704-8c30-f9f0-215b-7cdf4ad35a9a@molgen.mpg.de/ Cc: Jack Rosenthal Cc: Guenter Roeck Cc: Julius Werner Cc: Brian Norris Cc: Stephen Boyd Cc: Greg Kroah-Hartman Signed-off-by: Kees Cook Reviewed-by: Julius Werner Reviewed-by: Guenter Roeck Link: https://lore.kernel.org/r/20230107031406.gonna.761-kees@kernel.org Reviewed-by: Stephen Boyd Reviewed-by: Jack Rosenthal Link: https://lore.kernel.org/r/20230112230312.give.446-kees@kernel.org --- drivers/firmware/google/coreboot_table.c | 9 +++++++-- drivers/firmware/google/coreboot_table.h | 1 + 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c index 2652c396c42368..33ae94745aef97 100644 --- a/drivers/firmware/google/coreboot_table.c +++ b/drivers/firmware/google/coreboot_table.c @@ -93,14 +93,19 @@ static int coreboot_table_populate(struct device *dev, void *ptr) for (i = 0; i < header->table_entries; i++) { entry = ptr_entry; - device = kzalloc(sizeof(struct device) + entry->size, GFP_KERNEL); + if (entry->size < sizeof(*entry)) { + dev_warn(dev, "coreboot table entry too small!\n"); + return -EINVAL; + } + + device = kzalloc(sizeof(device->dev) + entry->size, GFP_KERNEL); if (!device) return -ENOMEM; device->dev.parent = dev; device->dev.bus = &coreboot_bus_type; device->dev.release = coreboot_device_release; - memcpy(&device->entry, ptr_entry, entry->size); + memcpy(device->raw, ptr_entry, entry->size); switch (device->entry.tag) { case LB_TAG_CBMEM_ENTRY: diff --git a/drivers/firmware/google/coreboot_table.h b/drivers/firmware/google/coreboot_table.h index 37f4d335a606d7..d814dca33a084c 100644 --- a/drivers/firmware/google/coreboot_table.h +++ b/drivers/firmware/google/coreboot_table.h @@ -79,6 +79,7 @@ struct coreboot_device { struct lb_cbmem_ref cbmem_ref; struct lb_cbmem_entry cbmem_entry; struct lb_framebuffer framebuffer; + DECLARE_FLEX_ARRAY(u8, raw); }; }; From 42633ed852deadc14d44660ad71e2f6640239120 Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Thu, 12 Jan 2023 22:49:48 +0000 Subject: [PATCH 2/5] kbuild: Fix CFI hash randomization with KASAN Clang emits a asan.module_ctor constructor to each object file when KASAN is enabled, and these functions are indirectly called in do_ctors. With CONFIG_CFI_CLANG, the compiler also emits a CFI type hash before each address-taken global function so they can pass indirect call checks. However, in commit 0c3e806ec0f9 ("x86/cfi: Add boot time hash randomization"), x86 implemented boot time hash randomization, which relies on the .cfi_sites section generated by objtool. As objtool is run against vmlinux.o instead of individual object files with X86_KERNEL_IBT (enabled by default), CFI types in object files that are not part of vmlinux.o end up not being included in .cfi_sites, and thus won't get randomized and trip CFI when called. Only .vmlinux.export.o and init/version-timestamp.o are linked into vmlinux separately from vmlinux.o. As these files don't contain any functions, disable KASAN for both of them to avoid breaking hash randomization. Link: https://github.com/ClangBuiltLinux/linux/issues/1742 Fixes: 0c3e806ec0f9 ("x86/cfi: Add boot time hash randomization") Signed-off-by: Sami Tolvanen Acked-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20230112224948.1479453-2-samitolvanen@google.com --- init/Makefile | 1 + scripts/Makefile.vmlinux | 1 + 2 files changed, 2 insertions(+) diff --git a/init/Makefile b/init/Makefile index 8316c23bead268..26de459006c4ee 100644 --- a/init/Makefile +++ b/init/Makefile @@ -59,3 +59,4 @@ include/generated/utsversion.h: FORCE $(obj)/version-timestamp.o: include/generated/utsversion.h CFLAGS_version-timestamp.o := -include include/generated/utsversion.h +KASAN_SANITIZE_version-timestamp.o := n diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux index 49946cb968440c..10176dec97eac2 100644 --- a/scripts/Makefile.vmlinux +++ b/scripts/Makefile.vmlinux @@ -18,6 +18,7 @@ quiet_cmd_cc_o_c = CC $@ $(call if_changed_dep,cc_o_c) ifdef CONFIG_MODULES +KASAN_SANITIZE_.vmlinux.export.o := n targets += .vmlinux.export.o vmlinux: .vmlinux.export.o endif From 4acf1de35f41549e60c3c02a8defa7cb95eabdf2 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 6 Jan 2023 19:47:05 -0800 Subject: [PATCH 3/5] kunit: memcpy: Split slow memcpy tests into MEMCPY_SLOW_KUNIT_TEST Since the long memcpy tests may stall a system for tens of seconds in virtualized architecture environments, split those tests off under CONFIG_MEMCPY_SLOW_KUNIT_TEST so they can be separately disabled. Reported-by: Guenter Roeck Link: https://lore.kernel.org/lkml/20221226195206.GA2626419@roeck-us.net Reviewed-by: Nick Desaulniers Reviewed-and-tested-by: Guenter Roeck Reviewed-by: David Gow Cc: Andrew Morton Cc: Nathan Chancellor Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook --- lib/Kconfig.debug | 9 +++++++++ lib/memcpy_kunit.c | 2 ++ 2 files changed, 11 insertions(+) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 881c3f84e88a32..149d6403b8a9b1 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2566,6 +2566,15 @@ config MEMCPY_KUNIT_TEST If unsure, say N. +config MEMCPY_SLOW_KUNIT_TEST + bool "Include exhaustive memcpy tests" + depends on MEMCPY_KUNIT_TEST + default y + help + Some memcpy tests are quite exhaustive in checking for overlaps + and bit ranges. These can be very slow, so they are split out + as a separate config, in case they need to be disabled. + config IS_SIGNED_TYPE_KUNIT_TEST tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS depends on KUNIT diff --git a/lib/memcpy_kunit.c b/lib/memcpy_kunit.c index 89128551448d10..887926f0473124 100644 --- a/lib/memcpy_kunit.c +++ b/lib/memcpy_kunit.c @@ -309,6 +309,8 @@ static void set_random_nonzero(struct kunit *test, u8 *byte) static void init_large(struct kunit *test) { + if (!IS_ENABLED(CONFIG_MEMCPY_SLOW_KUNIT_TEST)) + kunit_skip(test, "Slow test skipped. Enable with CONFIG_MEMCPY_SLOW_KUNIT_TEST=y"); /* Get many bit patterns. */ get_random_bytes(large_src, ARRAY_SIZE(large_src)); From e6a71160cc145e18ab45195abf89884112e02dfb Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 18 Jan 2023 12:21:35 -0800 Subject: [PATCH 4/5] gcc-plugins: Reorganize gimple includes for GCC 13 The gimple-iterator.h header must be included before gimple-fold.h starting with GCC 13. Reorganize gimple headers to work for all GCC versions. Reported-by: Palmer Dabbelt Acked-by: Palmer Dabbelt Link: https://lore.kernel.org/all/20230113173033.4380-1-palmer@rivosinc.com/ Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook --- scripts/gcc-plugins/gcc-common.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/scripts/gcc-plugins/gcc-common.h b/scripts/gcc-plugins/gcc-common.h index 9a1895747b1536..84c730da36dd3f 100644 --- a/scripts/gcc-plugins/gcc-common.h +++ b/scripts/gcc-plugins/gcc-common.h @@ -71,7 +71,9 @@ #include "varasm.h" #include "stor-layout.h" #include "internal-fn.h" +#include "gimple.h" #include "gimple-expr.h" +#include "gimple-iterator.h" #include "gimple-fold.h" #include "context.h" #include "tree-ssa-alias.h" @@ -85,10 +87,8 @@ #include "tree-eh.h" #include "stmt.h" #include "gimplify.h" -#include "gimple.h" #include "tree-phinodes.h" #include "tree-cfg.h" -#include "gimple-iterator.h" #include "gimple-ssa.h" #include "ssa-iterators.h" From be0d8f48ad97f5b775b0af3310343f676dbf318a Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 5 Jan 2023 22:02:33 -0800 Subject: [PATCH 5/5] bcache: Silence memcpy() run-time false positive warnings struct bkey has internal padding in a union, but it isn't always named the same (e.g. key ## _pad, key_p, etc). This makes it extremely hard for the compiler to reason about the available size of copies done against such keys. Use unsafe_memcpy() for now, to silence the many run-time false positive warnings: memcpy: detected field-spanning write (size 264) of single field "&i->j" at drivers/md/bcache/journal.c:152 (size 240) memcpy: detected field-spanning write (size 24) of single field "&b->key" at drivers/md/bcache/btree.c:939 (size 16) memcpy: detected field-spanning write (size 24) of single field "&temp.key" at drivers/md/bcache/extents.c:428 (size 16) Reported-by: Alexandre Pereira Link: https://bugzilla.kernel.org/show_bug.cgi?id=216785 Acked-by: Coly Li Cc: Kent Overstreet Cc: linux-bcache@vger.kernel.org Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20230106060229.never.047-kees@kernel.org --- drivers/md/bcache/bcache_ondisk.h | 3 ++- drivers/md/bcache/journal.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/md/bcache/bcache_ondisk.h b/drivers/md/bcache/bcache_ondisk.h index 97413586195b4c..f96034e0ba4f20 100644 --- a/drivers/md/bcache/bcache_ondisk.h +++ b/drivers/md/bcache/bcache_ondisk.h @@ -106,7 +106,8 @@ static inline unsigned long bkey_bytes(const struct bkey *k) return bkey_u64s(k) * sizeof(__u64); } -#define bkey_copy(_dest, _src) memcpy(_dest, _src, bkey_bytes(_src)) +#define bkey_copy(_dest, _src) unsafe_memcpy(_dest, _src, bkey_bytes(_src), \ + /* bkey is always padded */) static inline void bkey_copy_key(struct bkey *dest, const struct bkey *src) { diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c index e5da469a42357c..c182c21de2e819 100644 --- a/drivers/md/bcache/journal.c +++ b/drivers/md/bcache/journal.c @@ -149,7 +149,8 @@ reread: left = ca->sb.bucket_size - offset; bytes, GFP_KERNEL); if (!i) return -ENOMEM; - memcpy(&i->j, j, bytes); + unsafe_memcpy(&i->j, j, bytes, + /* "bytes" was calculated by set_bytes() above */); /* Add to the location after 'where' points to */ list_add(&i->list, where); ret = 1;