From ba1ee070909fae01248b8117da1706f3cf2bfd1b Mon Sep 17 00:00:00 2001 From: Salman Qazi Date: Fri, 5 Oct 2012 14:24:14 -0700 Subject: crypto: vmac - 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 Signed-off-by: Herbert Xu --- crypto/vmac.c | 47 +++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 43 insertions(+), 4 deletions(-) (limited to 'crypto/vmac.c') diff --git a/crypto/vmac.c b/crypto/vmac.c index f2338ca98368..2eb11a30c29c 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"); - -- cgit v1.2.3