From 7976c1492571a5fb234c416559a0d9790855c635 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 23 Feb 2022 08:07:01 +0100 Subject: crypto: crypto_xor - use helpers for unaligned accesses Dereferencing a misaligned pointer is undefined behavior in C, and may result in codegen on architectures such as ARM that trigger alignments traps and expensive fixups in software. Instead, use the get_aligned()/put_aligned() accessors, which are cheap or even completely free when CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y. In the converse case, the prior alignment checks ensure that the casts are safe, and so no unaligned accessors are necessary. Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu --- include/crypto/algapi.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'include/crypto') diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h index f76ec723ceae..f50c5d1725da 100644 --- a/include/crypto/algapi.h +++ b/include/crypto/algapi.h @@ -13,6 +13,8 @@ #include #include +#include + /* * Maximum values for blocksize and alignmask, used to allocate * static buffers that are big enough for any combination of @@ -154,9 +156,11 @@ static inline void crypto_xor(u8 *dst, const u8 *src, unsigned int size) (size % sizeof(unsigned long)) == 0) { unsigned long *d = (unsigned long *)dst; unsigned long *s = (unsigned long *)src; + unsigned long l; while (size > 0) { - *d++ ^= *s++; + l = get_unaligned(d) ^ get_unaligned(s++); + put_unaligned(l, d++); size -= sizeof(unsigned long); } } else { @@ -173,9 +177,11 @@ static inline void crypto_xor_cpy(u8 *dst, const u8 *src1, const u8 *src2, unsigned long *d = (unsigned long *)dst; unsigned long *s1 = (unsigned long *)src1; unsigned long *s2 = (unsigned long *)src2; + unsigned long l; while (size > 0) { - *d++ = *s1++ ^ *s2++; + l = get_unaligned(s1++) ^ get_unaligned(s2++); + put_unaligned(l, d++); size -= sizeof(unsigned long); } } else { -- cgit v1.2.3-58-ga151