[PATCH 6.6 2/3] s390/pkey: Wipe copies of clear-key structures on failure

[Nikita Zhandarovich]

From: Holger Dengler <dengler@xxxxxxxxxxxxx>

commit d65d76a44ffe74c73298ada25b0f578680576073 upstream.

Wipe all sensitive data from stack for all IOCTLs, which convert a
clear-key into a protected- or secure-key.

Reviewed-by: Harald Freudenberger <freude@xxxxxxxxxxxxx>
Reviewed-by: Ingo Franzki <ifranzki@xxxxxxxxxxxxx>
Acked-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Holger Dengler <dengler@xxxxxxxxxxxxx>
Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
[Nikita: small changes were made during cherry-picking due to
different debug macro use and similar discrepancies between branches]
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>
---
P.S. As no Fixes: tag was present, I decided against adding it myself
and leaving commit body intact.

 drivers/s390/crypto/pkey_api.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/s390/crypto/pkey_api.c b/drivers/s390/crypto/pkey_api.c
index 69bb4db78b69..87df60710ad3 100644
--- a/drivers/s390/crypto/pkey_api.c
+++ b/drivers/s390/crypto/pkey_api.c
@@ -1366,9 +1366,7 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
 		rc = cca_clr2seckey(kcs.cardnr, kcs.domain, kcs.keytype,
 				    kcs.clrkey.clrkey, kcs.seckey.seckey);
 		DEBUG_DBG("%s cca_clr2seckey()=%d\n", __func__, rc);
-		if (rc)
-			break;
-		if (copy_to_user(ucs, &kcs, sizeof(kcs)))
+		if (!rc && copy_to_user(ucs, &kcs, sizeof(kcs)))
 			rc = -EFAULT;
 		memzero_explicit(&kcs, sizeof(kcs));
 		break;
@@ -1401,9 +1399,7 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
 				      kcp.protkey.protkey,
 				      &kcp.protkey.len, &kcp.protkey.type);
 		DEBUG_DBG("%s pkey_clr2protkey()=%d\n", __func__, rc);
-		if (rc)
-			break;
-		if (copy_to_user(ucp, &kcp, sizeof(kcp)))
+		if (!rc && copy_to_user(ucp, &kcp, sizeof(kcp)))
 			rc = -EFAULT;
 		memzero_explicit(&kcp, sizeof(kcp));
 		break;
@@ -1554,11 +1550,14 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
 		if (copy_from_user(&kcs, ucs, sizeof(kcs)))
 			return -EFAULT;
 		apqns = _copy_apqns_from_user(kcs.apqns, kcs.apqn_entries);
-		if (IS_ERR(apqns))
+		if (IS_ERR(apqns)) {
+			memzero_explicit(&kcs, sizeof(kcs));
 			return PTR_ERR(apqns);
+		}
 		kkey = kzalloc(klen, GFP_KERNEL);
 		if (!kkey) {
 			kfree(apqns);
+			memzero_explicit(&kcs, sizeof(kcs));
 			return -ENOMEM;
 		}
 		rc = pkey_clr2seckey2(apqns, kcs.apqn_entries,
@@ -1568,15 +1567,18 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
 		kfree(apqns);
 		if (rc) {
 			kfree(kkey);
+			memzero_explicit(&kcs, sizeof(kcs));
 			break;
 		}
 		if (kcs.key) {
 			if (kcs.keylen < klen) {
 				kfree(kkey);
+				memzero_explicit(&kcs, sizeof(kcs));
 				return -EINVAL;
 			}
 			if (copy_to_user(kcs.key, kkey, klen)) {
 				kfree(kkey);
+				memzero_explicit(&kcs, sizeof(kcs));
 				return -EFAULT;
 			}
 		}
-- 
2.25.1