KEYS: Fix skcipher IV clobbering

The IV must not be modified by the skcipher operation so we need
to duplicate it.

Fixes: c3917fd9dfbc ("KEYS: Use skcipher")
Cc: stable@vger.kernel.org
Reported-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 7 insertions, 4 deletions

diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c
index 5adbfc32242f..17a06105ccb6 100644
--- a/security/keys/encrypted-keys/encrypted.c
+++ b/security/keys/encrypted-keys/encrypted.c
@@ -29,6 +29,7 @@
 #include <linux/rcupdate.h>
 #include <linux/scatterlist.h>
 #include <linux/ctype.h>
+#include <crypto/aes.h>
 #include <crypto/hash.h>
 #include <crypto/sha.h>
 #include <crypto/skcipher.h>
@@ -478,6 +479,7 @@ static int derived_key_encrypt(struct encrypted_key_payload *epayload,
         struct crypto_skcipher *tfm;
         struct skcipher_request *req;
         unsigned int encrypted_datalen;
+        u8 iv[AES_BLOCK_SIZE];
         unsigned int padlen;
         char pad[16];
         int ret;
@@ -500,8 +502,8 @@ static int derived_key_encrypt(struct encrypted_key_payload *epayload,
         sg_init_table(sg_out, 1);
         sg_set_buf(sg_out, epayload->encrypted_data, encrypted_datalen);
 
-        skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen,
-                                   epayload->iv);
+        memcpy(iv, epayload->iv, sizeof(iv));
+        skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen, iv);
         ret = crypto_skcipher_encrypt(req);
         tfm = crypto_skcipher_reqtfm(req);
         skcipher_request_free(req);
@@ -581,6 +583,7 @@ static int derived_key_decrypt(struct encrypted_key_payload *epayload,
         struct crypto_skcipher *tfm;
         struct skcipher_request *req;
         unsigned int encrypted_datalen;
+        u8 iv[AES_BLOCK_SIZE];
         char pad[16];
         int ret;
 
@@ -599,8 +602,8 @@ static int derived_key_decrypt(struct encrypted_key_payload *epayload,
                    epayload->decrypted_datalen);
         sg_set_buf(&sg_out[1], pad, sizeof pad);
 
-        skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen,
-                                   epayload->iv);
+        memcpy(iv, epayload->iv, sizeof(iv));
+        skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen, iv);
         ret = crypto_skcipher_decrypt(req);
         tfm = crypto_skcipher_reqtfm(req);
         skcipher_request_free(req);