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authorEric Biggers <ebiggers@google.com>2022-07-09 14:18:48 -0700
committerHerbert Xu <herbert@gondor.apana.org.au>2022-07-15 16:43:59 +0800
commit463f74089ff9148e3e46af454a6977d40b98cd10 (patch)
treeb49a09ad5e1a284fe7bc3741a4b66e3d84d5bed9 /lib/crypto
parent5a44749f65b2342d43dea82024e4febdac33c78d (diff)
crypto: lib - move lib/sha1.c into lib/crypto/
SHA-1 is a crypto algorithm (or at least was intended to be -- it's not considered secure anymore), so move it out of the top-level library directory and into lib/crypto/. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'lib/crypto')
-rw-r--r--lib/crypto/Makefile2
-rw-r--r--lib/crypto/sha1.c137
2 files changed, 139 insertions, 0 deletions
diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
index 26be2bbe09c5..d28111ba54fc 100644
--- a/lib/crypto/Makefile
+++ b/lib/crypto/Makefile
@@ -34,6 +34,8 @@ libpoly1305-y := poly1305-donna32.o
libpoly1305-$(CONFIG_ARCH_SUPPORTS_INT128) := poly1305-donna64.o
libpoly1305-y += poly1305.o
+obj-y += sha1.o
+
obj-$(CONFIG_CRYPTO_LIB_SHA256) += libsha256.o
libsha256-y := sha256.o
diff --git a/lib/crypto/sha1.c b/lib/crypto/sha1.c
new file mode 100644
index 000000000000..0494766fc574
--- /dev/null
+++ b/lib/crypto/sha1.c
@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SHA1 routine optimized to do word accesses rather than byte accesses,
+ * and to avoid unnecessary copies into the context array.
+ *
+ * This was based on the git SHA1 implementation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/bitops.h>
+#include <linux/string.h>
+#include <crypto/sha1.h>
+#include <asm/unaligned.h>
+
+/*
+ * If you have 32 registers or more, the compiler can (and should)
+ * try to change the array[] accesses into registers. However, on
+ * machines with less than ~25 registers, that won't really work,
+ * and at least gcc will make an unholy mess of it.
+ *
+ * So to avoid that mess which just slows things down, we force
+ * the stores to memory to actually happen (we might be better off
+ * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as
+ * suggested by Artur Skawina - that will also make gcc unable to
+ * try to do the silly "optimize away loads" part because it won't
+ * see what the value will be).
+ *
+ * Ben Herrenschmidt reports that on PPC, the C version comes close
+ * to the optimized asm with this (ie on PPC you don't want that
+ * 'volatile', since there are lots of registers).
+ *
+ * On ARM we get the best code generation by forcing a full memory barrier
+ * between each SHA_ROUND, otherwise gcc happily get wild with spilling and
+ * the stack frame size simply explode and performance goes down the drain.
+ */
+
+#ifdef CONFIG_X86
+ #define setW(x, val) (*(volatile __u32 *)&W(x) = (val))
+#elif defined(CONFIG_ARM)
+ #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0)
+#else
+ #define setW(x, val) (W(x) = (val))
+#endif
+
+/* This "rolls" over the 512-bit array */
+#define W(x) (array[(x)&15])
+
+/*
+ * Where do we get the source from? The first 16 iterations get it from
+ * the input data, the next mix it from the 512-bit array.
+ */
+#define SHA_SRC(t) get_unaligned_be32((__u32 *)data + t)
+#define SHA_MIX(t) rol32(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1)
+
+#define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
+ __u32 TEMP = input(t); setW(t, TEMP); \
+ E += TEMP + rol32(A,5) + (fn) + (constant); \
+ B = ror32(B, 2); \
+ TEMP = E; E = D; D = C; C = B; B = A; A = TEMP; } while (0)
+
+#define T_0_15(t, A, B, C, D, E) SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
+#define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
+#define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E )
+#define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E )
+#define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0xca62c1d6, A, B, C, D, E )
+
+/**
+ * sha1_transform - single block SHA1 transform (deprecated)
+ *
+ * @digest: 160 bit digest to update
+ * @data: 512 bits of data to hash
+ * @array: 16 words of workspace (see note)
+ *
+ * This function executes SHA-1's internal compression function. It updates the
+ * 160-bit internal state (@digest) with a single 512-bit data block (@data).
+ *
+ * Don't use this function. SHA-1 is no longer considered secure. And even if
+ * you do have to use SHA-1, this isn't the correct way to hash something with
+ * SHA-1 as this doesn't handle padding and finalization.
+ *
+ * Note: If the hash is security sensitive, the caller should be sure
+ * to clear the workspace. This is left to the caller to avoid
+ * unnecessary clears between chained hashing operations.
+ */
+void sha1_transform(__u32 *digest, const char *data, __u32 *array)
+{
+ __u32 A, B, C, D, E;
+ unsigned int i = 0;
+
+ A = digest[0];
+ B = digest[1];
+ C = digest[2];
+ D = digest[3];
+ E = digest[4];
+
+ /* Round 1 - iterations 0-16 take their input from 'data' */
+ for (; i < 16; ++i)
+ T_0_15(i, A, B, C, D, E);
+
+ /* Round 1 - tail. Input from 512-bit mixing array */
+ for (; i < 20; ++i)
+ T_16_19(i, A, B, C, D, E);
+
+ /* Round 2 */
+ for (; i < 40; ++i)
+ T_20_39(i, A, B, C, D, E);
+
+ /* Round 3 */
+ for (; i < 60; ++i)
+ T_40_59(i, A, B, C, D, E);
+
+ /* Round 4 */
+ for (; i < 80; ++i)
+ T_60_79(i, A, B, C, D, E);
+
+ digest[0] += A;
+ digest[1] += B;
+ digest[2] += C;
+ digest[3] += D;
+ digest[4] += E;
+}
+EXPORT_SYMBOL(sha1_transform);
+
+/**
+ * sha1_init - initialize the vectors for a SHA1 digest
+ * @buf: vector to initialize
+ */
+void sha1_init(__u32 *buf)
+{
+ buf[0] = 0x67452301;
+ buf[1] = 0xefcdab89;
+ buf[2] = 0x98badcfe;
+ buf[3] = 0x10325476;
+ buf[4] = 0xc3d2e1f0;
+}
+EXPORT_SYMBOL(sha1_init);