1 files changed, 39 insertions, 22 deletions

diff --git a/drivers/usb/wusbcore/crypto.c b/drivers/usb/wusbcore/crypto.c
index 79b2b628066d..79451f7ef1b7 100644
--- a/drivers/usb/wusbcore/crypto.c
+++ b/drivers/usb/wusbcore/crypto.c
@@ -133,6 +133,13 @@ static void bytewise_xor(void *_bo, const void *_bi1, const void *_bi2,
                 bo[itr] = bi1[itr] ^ bi2[itr];
 }
 
+/* Scratch space for MAC calculations. */
+struct wusb_mac_scratch {
+        struct aes_ccm_b0 b0;
+        struct aes_ccm_b1 b1;
+        struct aes_ccm_a ax;
+};
+
 /*
  * CC-MAC function WUSB1.0[6.5]
  *
@@ -197,16 +204,15 @@ static void bytewise_xor(void *_bo, const void *_bi1, const void *_bi2,
  *       what sg[4] is for. Maybe there is a smarter way to do this.
  */
 static int wusb_ccm_mac(struct crypto_skcipher *tfm_cbc,
-                        struct crypto_cipher *tfm_aes, void *mic,
+                        struct crypto_cipher *tfm_aes,
+                        struct wusb_mac_scratch *scratch,
+                        void *mic,
                         const struct aes_ccm_nonce *n,
                         const struct aes_ccm_label *a, const void *b,
                         size_t blen)
 {
         int result = 0;
         SKCIPHER_REQUEST_ON_STACK(req, tfm_cbc);
-        struct aes_ccm_b0 b0;
-        struct aes_ccm_b1 b1;
-        struct aes_ccm_a ax;
         struct scatterlist sg[4], sg_dst;
         void *dst_buf;
         size_t dst_size;
@@ -218,16 +224,17 @@ static int wusb_ccm_mac(struct crypto_skcipher *tfm_cbc,
          * These checks should be compile time optimized out
          * ensure @a fills b1's mac_header and following fields
          */
-        WARN_ON(sizeof(*a) != sizeof(b1) - sizeof(b1.la));
-        WARN_ON(sizeof(b0) != sizeof(struct aes_ccm_block));
-        WARN_ON(sizeof(b1) != sizeof(struct aes_ccm_block));
-        WARN_ON(sizeof(ax) != sizeof(struct aes_ccm_block));
+        WARN_ON(sizeof(*a) != sizeof(scratch->b1) - sizeof(scratch->b1.la));
+        WARN_ON(sizeof(scratch->b0) != sizeof(struct aes_ccm_block));
+        WARN_ON(sizeof(scratch->b1) != sizeof(struct aes_ccm_block));
+        WARN_ON(sizeof(scratch->ax) != sizeof(struct aes_ccm_block));
 
         result = -ENOMEM;
         zero_padding = blen % sizeof(struct aes_ccm_block);
         if (zero_padding)
                 zero_padding = sizeof(struct aes_ccm_block) - zero_padding;
-        dst_size = blen + sizeof(b0) + sizeof(b1) + zero_padding;
+        dst_size = blen + sizeof(scratch->b0) + sizeof(scratch->b1) +
+                zero_padding;
         dst_buf = kzalloc(dst_size, GFP_KERNEL);
         if (!dst_buf)
                 goto error_dst_buf;
@@ -235,9 +242,9 @@ static int wusb_ccm_mac(struct crypto_skcipher *tfm_cbc,
         memset(iv, 0, sizeof(iv));
 
         /* Setup B0 */
-        b0.flags = 0x59;        /* Format B0 */
-        b0.ccm_nonce = *n;
-        b0.lm = cpu_to_be16(0); /* WUSB1.0[6.5] sez l(m) is 0 */
+        scratch->b0.flags = 0x59;       /* Format B0 */
+        scratch->b0.ccm_nonce = *n;
+        scratch->b0.lm = cpu_to_be16(0);        /* WUSB1.0[6.5] sez l(m) is 0 */
 
         /* Setup B1
          *
@@ -246,12 +253,12 @@ static int wusb_ccm_mac(struct crypto_skcipher *tfm_cbc,
          * 14'--after clarification, it means to use A's contents
          * for MAC Header, EO, sec reserved and padding.
          */
-        b1.la = cpu_to_be16(blen + 14);
-        memcpy(&b1.mac_header, a, sizeof(*a));
+        scratch->b1.la = cpu_to_be16(blen + 14);
+        memcpy(&scratch->b1.mac_header, a, sizeof(*a));
 
         sg_init_table(sg, ARRAY_SIZE(sg));
-        sg_set_buf(&sg[0], &b0, sizeof(b0));
-        sg_set_buf(&sg[1], &b1, sizeof(b1));
+        sg_set_buf(&sg[0], &scratch->b0, sizeof(scratch->b0));
+        sg_set_buf(&sg[1], &scratch->b1, sizeof(scratch->b1));
         sg_set_buf(&sg[2], b, blen);
         /* 0 if well behaved :) */
         sg_set_buf(&sg[3], bzero, zero_padding);
@@ -276,11 +283,12 @@ static int wusb_ccm_mac(struct crypto_skcipher *tfm_cbc,
          * POS Crypto API: size is assumed to be AES's block size.
          * Thanks for documenting it -- tip taken from airo.c
          */
-        ax.flags = 0x01;                /* as per WUSB 1.0 spec */
-        ax.ccm_nonce = *n;
-        ax.counter = 0;
-        crypto_cipher_encrypt_one(tfm_aes, (void *)&ax, (void *)&ax);
-        bytewise_xor(mic, &ax, iv, 8);
+        scratch->ax.flags = 0x01;               /* as per WUSB 1.0 spec */
+        scratch->ax.ccm_nonce = *n;
+        scratch->ax.counter = 0;
+        crypto_cipher_encrypt_one(tfm_aes, (void *)&scratch->ax,
+                                  (void *)&scratch->ax);
+        bytewise_xor(mic, &scratch->ax, iv, 8);
         result = 8;
 error_cbc_crypt:
         kfree(dst_buf);
@@ -303,6 +311,7 @@ ssize_t wusb_prf(void *out, size_t out_size,
         struct aes_ccm_nonce n = *_n;
         struct crypto_skcipher *tfm_cbc;
         struct crypto_cipher *tfm_aes;
+        struct wusb_mac_scratch *scratch;
         u64 sfn = 0;
         __le64 sfn_le;
 
@@ -329,17 +338,25 @@ ssize_t wusb_prf(void *out, size_t out_size,
                 printk(KERN_ERR "E: can't set AES key: %d\n", (int)result);
                 goto error_setkey_aes;
         }
+        scratch = kmalloc(sizeof(*scratch), GFP_KERNEL);
+        if (!scratch) {
+                result = -ENOMEM;
+                goto error_alloc_scratch;
+        }
 
         for (bitr = 0; bitr < (len + 63) / 64; bitr++) {
                 sfn_le = cpu_to_le64(sfn++);
                 memcpy(&n.sfn, &sfn_le, sizeof(n.sfn)); /* n.sfn++... */
-                result = wusb_ccm_mac(tfm_cbc, tfm_aes, out + bytes,
+                result = wusb_ccm_mac(tfm_cbc, tfm_aes, scratch, out + bytes,
                                       &n, a, b, blen);
                 if (result < 0)
                         goto error_ccm_mac;
                 bytes += result;
         }
         result = bytes;
+
+        kfree(scratch);
+error_alloc_scratch:
 error_ccm_mac:
 error_setkey_aes:
         crypto_free_cipher(tfm_aes);