From 02205a347c40cfbcc5ce34e4ecd63ea821221237 Mon Sep 17 00:00:00 2001 From: Martin Wilck Date: Mon, 14 Aug 2017 22:12:38 +0200 Subject: BACKPORT: string.h: add memcpy_and_pad() commit 01f33c336e2d298ea5d4ce5d6e5bcd12865cc30f upstream. This helper function is useful for the nvme subsystem, and maybe others. Note: the warnings reported by the kbuild test robot for this patch are actually generated by the use of CONFIG_PROFILE_ALL_BRANCHES together with __FORTIFY_INLINE. Change-Id: I5f7e1e9143ce9df88af0afd02aef971d5172bd3e Signed-off-by: Martin Wilck Reviewed-by: Sagi Grimberg Signed-off-by: Christoph Hellwig [AG: Backported to 4.4] Signed-off-by: Alexander Grund --- include/linux/string.h | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'include/linux/string.h') diff --git a/include/linux/string.h b/include/linux/string.h index 1a9589a5ace6..84af888924e1 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -204,4 +204,33 @@ static inline const char *kbasename(const char *path) return tail ? tail + 1 : path; } +/** + * memcpy_and_pad - Copy one buffer to another with padding + * @dest: Where to copy to + * @dest_len: The destination buffer size + * @src: Where to copy from + * @count: The number of bytes to copy + * @pad: Character to use for padding if space is left in destination. + */ +__FORTIFY_INLINE void memcpy_and_pad(void *dest, size_t dest_len, + const void *src, size_t count, int pad) +{ + size_t dest_size = __builtin_object_size(dest, 0); + size_t src_size = __builtin_object_size(src, 0); + + if (__builtin_constant_p(dest_len) && __builtin_constant_p(count)) { + if (dest_size < dest_len && dest_size < count) + __write_overflow(); + else if (src_size < dest_len && src_size < count) + __read_overflow3(); + } + if (dest_size < dest_len) + fortify_panic(__func__); + if (dest_len > count) { + memcpy(dest, src, count); + memset(dest + count, pad, dest_len - count); + } else + memcpy(dest, src, dest_len); +} + #endif /* _LINUX_STRING_H_ */ -- cgit v1.2.3