crypto: talitos – Do not modify req->cryptlen on decryption. [Linux 5.3]

This Linux kernel change "crypto: talitos – Do not modify req->cryptlen on decryption" is included in the Linux 5.3 release. This change is authored by Christophe Leroy <christophe.leroy [at] c-s.fr> on Tue May 21 13:34:14 2019 +0000. The commit for this change in Linux stable tree is 7ede4c3 (patch).

crypto: talitos - Do not modify req->cryptlen on decryption.

For decrypt, req->cryptlen includes the size of the authentication
part while all functions of the driver expect cryptlen to be
the size of the encrypted data.

As it is not expected to change req->cryptlen, this patch
implements local calculation of cryptlen.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Fixes: 9c4a79653b35 ("crypto: talitos - Freescale integrated security engine (SEC) driver")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

There are 31 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/crypto/talitos.c | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/crypto/talitos.c b/drivers/crypto/talitos.c
index 6f6f347..a15aa6d 100644
--- a/drivers/crypto/talitos.c
+++ b/drivers/crypto/talitos.c
@@ -1025,11 +1025,13 @@ static void talitos_sg_unmap(struct device *dev,

 static void ipsec_esp_unmap(struct device *dev,
                struct talitos_edesc *edesc,
-               struct aead_request *areq)
+               struct aead_request *areq, bool encrypt)
 {
    struct crypto_aead *aead = crypto_aead_reqtfm(areq);
    struct talitos_ctx *ctx = crypto_aead_ctx(aead);
    unsigned int ivsize = crypto_aead_ivsize(aead);
+   unsigned int authsize = crypto_aead_authsize(aead);
+   unsigned int cryptlen = areq->cryptlen - (encrypt ? 0 : authsize);
    bool is_ipsec_esp = edesc->desc.hdr & DESC_HDR_TYPE_IPSEC_ESP;
    struct talitos_ptr *civ_ptr = &edesc->desc.ptr[is_ipsec_esp ? 2 : 3];

@@ -1038,7 +1040,7 @@ static void ipsec_esp_unmap(struct device *dev,
                     DMA_FROM_DEVICE);
    unmap_single_talitos_ptr(dev, civ_ptr, DMA_TO_DEVICE);

-   talitos_sg_unmap(dev, edesc, areq->src, areq->dst, areq->cryptlen,
+   talitos_sg_unmap(dev, edesc, areq->src, areq->dst, cryptlen,
             areq->assoclen);

    if (edesc->dma_len)
@@ -1049,7 +1051,7 @@ static void ipsec_esp_unmap(struct device *dev,
        unsigned int dst_nents = edesc->dst_nents ? : 1;

        sg_pcopy_to_buffer(areq->dst, dst_nents, ctx->iv, ivsize,
-                  areq->assoclen + areq->cryptlen - ivsize);
+                  areq->assoclen + cryptlen - ivsize);
    }
 }

@@ -1072,7 +1074,7 @@ static void ipsec_esp_encrypt_done(struct device *dev,

    edesc = container_of(desc, struct talitos_edesc, desc);

-   ipsec_esp_unmap(dev, edesc, areq);
+   ipsec_esp_unmap(dev, edesc, areq, true);

    /* copy the generated ICV to dst */
    if (edesc->icv_ool) {
@@ -1108,7 +1110,7 @@ static void ipsec_esp_decrypt_swauth_done(struct device *dev,

    edesc = container_of(desc, struct talitos_edesc, desc);

-   ipsec_esp_unmap(dev, edesc, req);
+   ipsec_esp_unmap(dev, edesc, req, false);

    if (!err) {
        /* auth check */
@@ -1145,7 +1147,7 @@ static void ipsec_esp_decrypt_hwauth_done(struct device *dev,

    edesc = container_of(desc, struct talitos_edesc, desc);

-   ipsec_esp_unmap(dev, edesc, req);
+   ipsec_esp_unmap(dev, edesc, req, false);

    /* check ICV auth status */
    if (!err && ((desc->hdr_lo & DESC_HDR_LO_ICCR1_MASK) !=
@@ -1248,6 +1250,7 @@ static int talitos_sg_map(struct device *dev, struct scatterlist *src,
  * fill in and submit ipsec_esp descriptor
  */
 static int ipsec_esp(struct talitos_edesc *edesc, struct aead_request *areq,
+            bool encrypt,
             void (*callback)(struct device *dev,
                      struct talitos_desc *desc,
                      void *context, int error))
@@ -1257,7 +1260,7 @@ static int ipsec_esp(struct talitos_edesc *edesc, struct aead_request *areq,
    struct talitos_ctx *ctx = crypto_aead_ctx(aead);
    struct device *dev = ctx->dev;
    struct talitos_desc *desc = &edesc->desc;
-   unsigned int cryptlen = areq->cryptlen;
+   unsigned int cryptlen = areq->cryptlen - (encrypt ? 0 : authsize);
    unsigned int ivsize = crypto_aead_ivsize(aead);
    int tbl_off = 0;
    int sg_count, ret;
@@ -1384,7 +1387,7 @@ static int ipsec_esp(struct talitos_edesc *edesc, struct aead_request *areq,

    ret = talitos_submit(dev, ctx->ch, desc, callback, areq);
    if (ret != -EINPROGRESS) {
-       ipsec_esp_unmap(dev, edesc, areq);
+       ipsec_esp_unmap(dev, edesc, areq, encrypt);
        kfree(edesc);
    }
    return ret;
@@ -1502,9 +1505,10 @@ static struct talitos_edesc *aead_edesc_alloc(struct aead_request *areq, u8 *iv,
    unsigned int authsize = crypto_aead_authsize(authenc);
    struct talitos_ctx *ctx = crypto_aead_ctx(authenc);
    unsigned int ivsize = crypto_aead_ivsize(authenc);
+   unsigned int cryptlen = areq->cryptlen - (encrypt ? 0 : authsize);

    return talitos_edesc_alloc(ctx->dev, areq->src, areq->dst,
-                  iv, areq->assoclen, areq->cryptlen,
+                  iv, areq->assoclen, cryptlen,
                   authsize, ivsize, icv_stashing,
                   areq->base.flags, encrypt);
 }
@@ -1523,7 +1527,7 @@ static int aead_encrypt(struct aead_request *req)
    /* set encrypt */
    edesc->desc.hdr = ctx->desc_hdr_template | DESC_HDR_MODE0_ENCRYPT;

-   return ipsec_esp(edesc, req, ipsec_esp_encrypt_done);
+   return ipsec_esp(edesc, req, true, ipsec_esp_encrypt_done);
 }

 static int aead_decrypt(struct aead_request *req)
@@ -1536,8 +1540,6 @@ static int aead_decrypt(struct aead_request *req)
    struct scatterlist *sg;
    void *icvdata;

-   req->cryptlen -= authsize;
-
    /* allocate extended descriptor */
    edesc = aead_edesc_alloc(req, req->iv, 1, false);
    if (IS_ERR(edesc))
@@ -1554,7 +1556,8 @@ static int aead_decrypt(struct aead_request *req)

        /* reset integrity check result bits */

-       return ipsec_esp(edesc, req, ipsec_esp_decrypt_hwauth_done);
+       return ipsec_esp(edesc, req, false,
+                ipsec_esp_decrypt_hwauth_done);
    }

    /* Have to check the ICV with software */
@@ -1571,7 +1574,7 @@ static int aead_decrypt(struct aead_request *req)

    memcpy(icvdata, (char *)sg_virt(sg) + sg->length - authsize, authsize);

-   return ipsec_esp(edesc, req, ipsec_esp_decrypt_swauth_done);
+   return ipsec_esp(edesc, req, false, ipsec_esp_decrypt_swauth_done);
 }

 static int ablkcipher_setkey(struct crypto_ablkcipher *cipher,

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