[PATCH] KEYS: trusted: fix a couple error pointer dereferences

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

If registering "reg_shm_out" fails, then it is an error pointer and the
error handling will call tee_shm_free(reg_shm_out) which leads to an
error pointer dereference and an Oops.

I've re-arranged it so we only free things that have been allocated
successfully.

Fixes: 6dd95e650c8a ("KEYS: trusted: Introduce TEE based Trusted Keys")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
 security/keys/trusted-keys/trusted_tee.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/security/keys/trusted-keys/trusted_tee.c b/security/keys/trusted-keys/trusted_tee.c
index 2ce66c199e1d..45f96f6ed673 100644
--- a/security/keys/trusted-keys/trusted_tee.c
+++ b/security/keys/trusted-keys/trusted_tee.c
@@ -65,7 +65,7 @@ static int trusted_tee_seal(struct trusted_key_payload *p, char *datablob)
 	int ret;
 	struct tee_ioctl_invoke_arg inv_arg;
 	struct tee_param param[4];
-	struct tee_shm *reg_shm_in = NULL, *reg_shm_out = NULL;
+	struct tee_shm *reg_shm_in, *reg_shm_out;
 
 	memset(&inv_arg, 0, sizeof(inv_arg));
 	memset(&param, 0, sizeof(param));
@@ -84,7 +84,7 @@ static int trusted_tee_seal(struct trusted_key_payload *p, char *datablob)
 	if (IS_ERR(reg_shm_out)) {
 		dev_err(pvt_data.dev, "blob shm register failed\n");
 		ret = PTR_ERR(reg_shm_out);
-		goto out;
+		goto free_shm_in;
 	}
 
 	inv_arg.func = TA_CMD_SEAL;
@@ -109,11 +109,9 @@ static int trusted_tee_seal(struct trusted_key_payload *p, char *datablob)
 		p->blob_len = param[1].u.memref.size;
 	}
 
-out:
-	if (reg_shm_out)
-		tee_shm_free(reg_shm_out);
-	if (reg_shm_in)
-		tee_shm_free(reg_shm_in);
+	tee_shm_free(reg_shm_out);
+free_shm_in:
+	tee_shm_free(reg_shm_in);
 
 	return ret;
 }
@@ -126,7 +124,7 @@ static int trusted_tee_unseal(struct trusted_key_payload *p, char *datablob)
 	int ret;
 	struct tee_ioctl_invoke_arg inv_arg;
 	struct tee_param param[4];
-	struct tee_shm *reg_shm_in = NULL, *reg_shm_out = NULL;
+	struct tee_shm *reg_shm_in, *reg_shm_out;
 
 	memset(&inv_arg, 0, sizeof(inv_arg));
 	memset(&param, 0, sizeof(param));
@@ -145,7 +143,7 @@ static int trusted_tee_unseal(struct trusted_key_payload *p, char *datablob)
 	if (IS_ERR(reg_shm_out)) {
 		dev_err(pvt_data.dev, "key shm register failed\n");
 		ret = PTR_ERR(reg_shm_out);
-		goto out;
+		goto free_shm_in;
 	}
 
 	inv_arg.func = TA_CMD_UNSEAL;
@@ -170,11 +168,9 @@ static int trusted_tee_unseal(struct trusted_key_payload *p, char *datablob)
 		p->key_len = param[1].u.memref.size;
 	}
 
-out:
-	if (reg_shm_out)
-		tee_shm_free(reg_shm_out);
-	if (reg_shm_in)
-		tee_shm_free(reg_shm_in);
+	tee_shm_free(reg_shm_out);
+free_shm_in:
+	tee_shm_free(reg_shm_in);
 
 	return ret;
 }
-- 
2.30.2