From 917cda2790c4bd624c5191b8d9edd12121749e86 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Wed, 25 Sep 2019 16:46:13 -0700 Subject: kernel-doc: core-api: include string.h into core-api core-api should show all the various string functions including the newly added stracpy and stracpy_pad. Miscellanea: o Update the Returns: value for strscpy o fix a defect with %NUL) [joe@perches.com: correct return of -E2BIG descriptions] Link: http://lkml.kernel.org/r/29f998b4c1a9d69fbeae70500ba0daa4b340c546.1563889130.git.joe@perches.com Link: http://lkml.kernel.org/r/224a6ebf39955f4107c0c376d66155d970e46733.1563841972.git.joe@perches.com Signed-off-by: Joe Perches Reviewed-by: Kees Cook Cc: Jonathan Corbet Cc: Stephen Kitt Cc: Nitin Gote Cc: Rasmus Villemoes Cc: Jann Horn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/string.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux/string.h') diff --git a/include/linux/string.h b/include/linux/string.h index 4deb11f7976b..b2f9df7f0761 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -474,8 +474,9 @@ static inline void memcpy_and_pad(void *dest, size_t dest_len, * But this can lead to bugs due to typos, or if prefix is a pointer * and not a constant. Instead use str_has_prefix(). * - * Returns: 0 if @str does not start with @prefix - strlen(@prefix) if @str does start with @prefix + * Returns: + * * strlen(@prefix) if @str starts with @prefix + * * 0 if @str does not start with @prefix */ static __always_inline size_t str_has_prefix(const char *str, const char *prefix) { -- cgit v1.2.3 From bec500777089b3c96c53681fc0aa6fee59711d4a Mon Sep 17 00:00:00 2001 From: Arvind Sankar Date: Mon, 7 Oct 2019 18:00:02 -0400 Subject: lib/string: Make memzero_explicit() inline instead of external With the use of the barrier implied by barrier_data(), there is no need for memzero_explicit() to be extern. Making it inline saves the overhead of a function call, and allows the code to be reused in arch/*/purgatory without having to duplicate the implementation. Tested-by: Hans de Goede Signed-off-by: Arvind Sankar Reviewed-by: Hans de Goede Cc: Ard Biesheuvel Cc: Borislav Petkov Cc: H . Peter Anvin Cc: Herbert Xu Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephan Mueller Cc: Thomas Gleixner Cc: linux-crypto@vger.kernel.org Cc: linux-s390@vger.kernel.org Fixes: 906a4bb97f5d ("crypto: sha256 - Use get/put_unaligned_be32 to get input, memzero_explicit") Link: https://lkml.kernel.org/r/20191007220000.GA408752@rani.riverdale.lan Signed-off-by: Ingo Molnar --- include/linux/string.h | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) (limited to 'include/linux/string.h') diff --git a/include/linux/string.h b/include/linux/string.h index b2f9df7f0761..b6ccdc2c7f02 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -227,7 +227,26 @@ static inline bool strstarts(const char *str, const char *prefix) } size_t memweight(const void *ptr, size_t bytes); -void memzero_explicit(void *s, size_t count); + +/** + * memzero_explicit - Fill a region of memory (e.g. sensitive + * keying data) with 0s. + * @s: Pointer to the start of the area. + * @count: The size of the area. + * + * Note: usually using memset() is just fine (!), but in cases + * where clearing out _local_ data at the end of a scope is + * necessary, memzero_explicit() should be used instead in + * order to prevent the compiler from optimising away zeroing. + * + * memzero_explicit() doesn't need an arch-specific version as + * it just invokes the one of memset() implicitly. + */ +static inline void memzero_explicit(void *s, size_t count) +{ + memset(s, 0, count); + barrier_data(s); +} /** * kbasename - return the last part of a pathname. -- cgit v1.2.3