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authorArd Biesheuvel <ardb@kernel.org>2022-02-23 08:07:01 +0100
committerHerbert Xu <herbert@gondor.apana.org.au>2022-03-03 10:49:20 +1200
commit7976c1492571a5fb234c416559a0d9790855c635 (patch)
tree34d455af015e3256902f25da54e17bb52c5aeed5 /include/crypto
parent4920a4a7262dd1c647b515c05358ccbee0ab828c (diff)
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 <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'include/crypto')
-rw-r--r--include/crypto/algapi.h10
1 files changed, 8 insertions, 2 deletions
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 <linux/list.h>
#include <linux/types.h>
+#include <asm/unaligned.h>
+
/*
* 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 {