Memory accesses in copy_mc_to_kernel() and copy_mc_to_user() are performed by assembly routines and are invisible to KASAN, KCSAN, and KMSAN. Add hooks from instrumentation.h to tell the tools these functions have memcpy/copy_from_user semantics. The call to copy_mc_fragile() in copy_mc_fragile_handle_tail() is left intact, because the latter is only called from the assembly implementation of copy_mc_fragile(), so the memory accesses in it are covered by the instrumentation in copy_mc_to_kernel() and copy_mc_to_user(). Link: https://lore.kernel.org/all/3b7dbd88-0861-4638-b2d2-911c97a4cadf@xxxxxxxxxxxxxxxxxxx/ Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> --- v2: - as requested by Linus Torvalds, move the instrumentation outside the uaccess section --- arch/x86/lib/copy_mc.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/arch/x86/lib/copy_mc.c b/arch/x86/lib/copy_mc.c index 6e8b7e600def5..97e88e58567bf 100644 --- a/arch/x86/lib/copy_mc.c +++ b/arch/x86/lib/copy_mc.c @@ -4,6 +4,7 @@ #include <linux/jump_label.h> #include <linux/uaccess.h> #include <linux/export.h> +#include <linux/instrumented.h> #include <linux/string.h> #include <linux/types.h> @@ -61,10 +62,20 @@ unsigned long copy_mc_enhanced_fast_string(void *dst, const void *src, unsigned */ unsigned long __must_check copy_mc_to_kernel(void *dst, const void *src, unsigned len) { - if (copy_mc_fragile_enabled) - return copy_mc_fragile(dst, src, len); - if (static_cpu_has(X86_FEATURE_ERMS)) - return copy_mc_enhanced_fast_string(dst, src, len); + unsigned long ret; + + if (copy_mc_fragile_enabled) { + instrument_memcpy_before(dst, src, len); + ret = copy_mc_fragile(dst, src, len); + instrument_memcpy_after(dst, src, len, ret); + return ret; + } + if (static_cpu_has(X86_FEATURE_ERMS)) { + instrument_memcpy_before(dst, src, len); + ret = copy_mc_enhanced_fast_string(dst, src, len); + instrument_memcpy_after(dst, src, len, ret); + return ret; + } memcpy(dst, src, len); return 0; } @@ -75,6 +86,7 @@ unsigned long __must_check copy_mc_to_user(void __user *dst, const void *src, un unsigned long ret; if (copy_mc_fragile_enabled) { + instrument_copy_to_user(dst, src, len); __uaccess_begin(); ret = copy_mc_fragile((__force void *)dst, src, len); __uaccess_end(); @@ -82,6 +94,7 @@ unsigned long __must_check copy_mc_to_user(void __user *dst, const void *src, un } if (static_cpu_has(X86_FEATURE_ERMS)) { + instrument_copy_to_user(dst, src, len); __uaccess_begin(); ret = copy_mc_enhanced_fast_string((__force void *)dst, src, len); __uaccess_end(); -- 2.44.0.291.gc1ea87d7ee-goog
