sunrpc: Fix skcipher/shash conversion

The skcpiher/shash conversion introduced a number of bugs in the
sunrpc code:

1) Missing calls to skcipher_request_set_tfm lead to crashes.
2) The allocation size of shash_desc is too small which leads to
memory corruption.

Fixes: 3b5cf20cf439 ("sunrpc: Use skcipher and ahash/shash")
Reported-by: J. Bruce Fields <bfields@fieldses.org>
Tested-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

2 files changed, 8 insertions, 3 deletions

diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
index d94a8e1e9f05..da26455cf86c 100644
--- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
+++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
@@ -78,6 +78,7 @@ krb5_encrypt(
         memcpy(out, in, length);
         sg_init_one(sg, out, length);
 
+        skcipher_request_set_tfm(req, tfm);
         skcipher_request_set_callback(req, 0, NULL, NULL);
         skcipher_request_set_crypt(req, sg, sg, length, local_iv);
 
@@ -115,6 +116,7 @@ krb5_decrypt(
         memcpy(out, in, length);
         sg_init_one(sg, out, length);
 
+        skcipher_request_set_tfm(req, tfm);
         skcipher_request_set_callback(req, 0, NULL, NULL);
         skcipher_request_set_crypt(req, sg, sg, length, local_iv);
 
@@ -946,7 +948,8 @@ krb5_rc4_setup_seq_key(struct krb5_ctx *kctx, struct crypto_skcipher *cipher,
                 return PTR_ERR(hmac);
         }
 
-        desc = kmalloc(sizeof(*desc), GFP_KERNEL);
+        desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
+                       GFP_KERNEL);
         if (!desc) {
                 dprintk("%s: failed to allocate shash descriptor for '%s'\n",
                         __func__, kctx->gk5e->cksum_name);
@@ -1012,7 +1015,8 @@ krb5_rc4_setup_enc_key(struct krb5_ctx *kctx, struct crypto_skcipher *cipher,
                 return PTR_ERR(hmac);
         }
 
-        desc = kmalloc(sizeof(*desc), GFP_KERNEL);
+        desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
+                       GFP_KERNEL);
         if (!desc) {
                 dprintk("%s: failed to allocate shash descriptor for '%s'\n",
                         __func__, kctx->gk5e->cksum_name);
diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c
index 71341ccb9890..65427492b1c9 100644
--- a/net/sunrpc/auth_gss/gss_krb5_mech.c
+++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
@@ -451,7 +451,8 @@ context_derive_keys_rc4(struct krb5_ctx *ctx)
                 goto out_err_free_hmac;
 
 
-        desc = kmalloc(sizeof(*desc), GFP_KERNEL);
+        desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
+                       GFP_KERNEL);
         if (!desc) {
                 dprintk("%s: failed to allocate hash descriptor for '%s'\n",
                         __func__, ctx->gk5e->cksum_name);