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Date: Fri, 05 Oct 2012 14:24:14 -0700
From: Salman Qazi <sqazi@...gle.com>
To: Shane Wang <shane.wang@...el.com>,
Joseph Cihula <joseph.cihula@...el.com>,
Herbert Xu <herbert@...dor.apana.org.au>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] crypto: Make VMAC work when blocks aren't aligned
VMAC implementation, as it is, does not work with blocks that
are not multiples of 128-bytes. Furthermore, this is a problem
when using the implementation on scatterlists, even
when the complete plain text is 128-byte multiple, as the pieces
that get passed to vmac_update can be pretty much any size.
I also added test cases for unaligned blocks.
Signed-off-by: Salman Qazi <sqazi@...gle.com>
---
crypto/testmgr.h | 33 ++++++++++++++++++++++++++++++++-
crypto/vmac.c | 47 +++++++++++++++++++++++++++++++++++++++++++----
include/crypto/vmac.h | 2 ++
3 files changed, 77 insertions(+), 5 deletions(-)
diff --git a/crypto/testmgr.h b/crypto/testmgr.h
index 76d7f6c..f8365e9 100644
--- a/crypto/testmgr.h
+++ b/crypto/testmgr.h
@@ -1707,7 +1707,7 @@ static struct hash_testvec aes_xcbc128_tv_template[] = {
}
};
-#define VMAC_AES_TEST_VECTORS 8
+#define VMAC_AES_TEST_VECTORS 11
static char vmac_string1[128] = {'\x01', '\x01', '\x01', '\x01',
'\x02', '\x03', '\x02', '\x02',
'\x02', '\x04', '\x01', '\x07',
@@ -1723,6 +1723,19 @@ static char vmac_string3[128] = {'a', 'b', 'c', 'a', 'b', 'c',
'a', 'b', 'c', 'a', 'b', 'c',
};
+static char vmac_string4[17] = {'b', 'c', 'e', 'f',
+ 'i', 'j', 'l', 'm',
+ 'o', 'p', 'r', 's',
+ 't', 'u', 'w', 'x', 'z'};
+
+static char vmac_string5[127] = {'r', 'm', 'b', 't', 'c',
+ 'o', 'l', 'k', ']', '%',
+ '9', '2', '7', '!', 'A'};
+
+static char vmac_string6[129] = {'p', 't', '*', '7', 'l',
+ 'i', '!', '#', 'w', '0',
+ 'z', '/', '4', 'A', 'n'};
+
static struct hash_testvec aes_vmac128_tv_template[] = {
{
.key = "\x00\x01\x02\x03\x04\x05\x06\x07"
@@ -1776,6 +1789,24 @@ static struct hash_testvec aes_vmac128_tv_template[] = {
.digest = "\x8b\x32\x8f\xe1\xed\x8f\xfa\xd4",
.psize = 128,
.ksize = 16,
+ }, {
+ .key = "a09b5cd!f#07K\x00\x00\x00",
+ .plaintext = vmac_string4,
+ .digest = "\xab\xa5\x0f\xea\x42\x4e\xa1\x5f",
+ .psize = sizeof(vmac_string4),
+ .ksize = 16,
+ }, {
+ .key = "a09b5cd!f#07K\x00\x00\x00",
+ .plaintext = vmac_string5,
+ .digest = "\x25\x31\x98\xbc\x1d\xe8\x67\x60",
+ .psize = sizeof(vmac_string5),
+ .ksize = 16,
+ }, {
+ .key = "a09b5cd!f#07K\x00\x00\x00",
+ .plaintext = vmac_string6,
+ .digest = "\xc4\xae\x9b\x47\x95\x65\xeb\x41",
+ .psize = sizeof(vmac_string6),
+ .ksize = 16,
},
};
diff --git a/crypto/vmac.c b/crypto/vmac.c
index f2338ca..2eb11a3 100644
--- a/crypto/vmac.c
+++ b/crypto/vmac.c
@@ -375,6 +375,11 @@ static void vhash_update(const unsigned char *m,
u64 pkh = ctx->polykey[0];
u64 pkl = ctx->polykey[1];
+ if (!mbytes)
+ return;
+
+ BUG_ON(mbytes % VMAC_NHBYTES);
+
mptr = (u64 *)m;
i = mbytes / VMAC_NHBYTES; /* Must be non-zero */
@@ -454,7 +459,7 @@ do_l3:
}
static u64 vmac(unsigned char m[], unsigned int mbytes,
- unsigned char n[16], u64 *tagl,
+ const unsigned char n[16], u64 *tagl,
struct vmac_ctx_t *ctx)
{
u64 *in_n, *out_p;
@@ -559,8 +564,33 @@ static int vmac_update(struct shash_desc *pdesc, const u8 *p,
{
struct crypto_shash *parent = pdesc->tfm;
struct vmac_ctx_t *ctx = crypto_shash_ctx(parent);
+ int expand;
+ int min;
+
+ expand = VMAC_NHBYTES - ctx->partial_size > 0 ?
+ VMAC_NHBYTES - ctx->partial_size : 0;
+
+ min = len < expand ? len : expand;
+
+ memcpy(ctx->partial + ctx->partial_size, p, min);
+ ctx->partial_size += min;
+
+ if (len < expand)
+ return 0;
- vhash_update(p, len, &ctx->__vmac_ctx);
+ vhash_update(ctx->partial, VMAC_NHBYTES, &ctx->__vmac_ctx);
+ ctx->partial_size = 0;
+
+ len -= expand;
+ p += expand;
+
+ if (len % VMAC_NHBYTES) {
+ memcpy(ctx->partial, p + len - (len % VMAC_NHBYTES),
+ len % VMAC_NHBYTES);
+ ctx->partial_size = len % VMAC_NHBYTES;
+ }
+
+ vhash_update(p, len - len % VMAC_NHBYTES, &ctx->__vmac_ctx);
return 0;
}
@@ -572,10 +602,20 @@ static int vmac_final(struct shash_desc *pdesc, u8 *out)
vmac_t mac;
u8 nonce[16] = {};
- mac = vmac(NULL, 0, nonce, NULL, ctx);
+ /* vmac() ends up accessing outside the array bounds that
+ * we specify. In appears to access up to the next 2-word
+ * boundary. We'll just be uber cautious and zero the
+ * unwritten bytes in the buffer.
+ */
+ if (ctx->partial_size) {
+ memset(ctx->partial + ctx->partial_size, 0,
+ VMAC_NHBYTES - ctx->partial_size);
+ }
+ mac = vmac(ctx->partial, ctx->partial_size, nonce, NULL, ctx);
memcpy(out, &mac, sizeof(vmac_t));
memset(&mac, 0, sizeof(vmac_t));
memset(&ctx->__vmac_ctx, 0, sizeof(struct vmac_ctx));
+ ctx->partial_size = 0;
return 0;
}
@@ -673,4 +713,3 @@ module_exit(vmac_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("VMAC hash algorithm");
-
diff --git a/include/crypto/vmac.h b/include/crypto/vmac.h
index c4467c5..6b700c7 100644
--- a/include/crypto/vmac.h
+++ b/include/crypto/vmac.h
@@ -56,6 +56,8 @@ typedef u64 vmac_t;
struct vmac_ctx_t {
struct crypto_cipher *child;
struct vmac_ctx __vmac_ctx;
+ u8 partial[VMAC_NHBYTES]; /* partial block */
+ int partial_size; /* size of the partial block */
};
#endif /* __CRYPTO_VMAC_H */
--
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