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| author | Ard Biesheuvel <ardb@kernel.org> | 2022-02-23 08:07:01 +0100 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2022-03-03 10:49:20 +1200 |
| commit | ad91155d98938a18a52d582af1d6d3d924e867ce (patch) | |
| tree | 508062f60ecba3eece0b673d8f0bcbd3f53c4be0 /crypto/algapi.c | |
| parent | 0a51cda331bd1374440b5b66547f2389eb57e1e2 (diff) | |
| download | linux-crypto-ad91155d98938a18a52d582af1d6d3d924e867ce.tar.gz linux-crypto-ad91155d98938a18a52d582af1d6d3d924e867ce.zip | |
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 'crypto/algapi.c')
| -rw-r--r-- | crypto/algapi.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/crypto/algapi.c b/crypto/algapi.c index 53c5149e..b078e7a6 100644 --- a/crypto/algapi.c +++ b/crypto/algapi.c @@ -1022,7 +1022,13 @@ void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int len) } while (IS_ENABLED(CONFIG_64BIT) && len >= 8 && !(relalign & 7)) { - *(u64 *)dst = *(u64 *)src1 ^ *(u64 *)src2; + if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) { + u64 l = get_unaligned((u64 *)src1) ^ + get_unaligned((u64 *)src2); + put_unaligned(l, (u64 *)dst); + } else { + *(u64 *)dst = *(u64 *)src1 ^ *(u64 *)src2; + } dst += 8; src1 += 8; src2 += 8; @@ -1030,7 +1036,13 @@ void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int len) } while (len >= 4 && !(relalign & 3)) { - *(u32 *)dst = *(u32 *)src1 ^ *(u32 *)src2; + if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) { + u32 l = get_unaligned((u32 *)src1) ^ + get_unaligned((u32 *)src2); + put_unaligned(l, (u32 *)dst); + } else { + *(u32 *)dst = *(u32 *)src1 ^ *(u32 *)src2; + } dst += 4; src1 += 4; src2 += 4; @@ -1038,7 +1050,13 @@ void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int len) } while (len >= 2 && !(relalign & 1)) { - *(u16 *)dst = *(u16 *)src1 ^ *(u16 *)src2; + if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) { + u16 l = get_unaligned((u16 *)src1) ^ + get_unaligned((u16 *)src2); + put_unaligned(l, (u16 *)dst); + } else { + *(u16 *)dst = *(u16 *)src1 ^ *(u16 *)src2; + } dst += 2; src1 += 2; src2 += 2; |