s390/pkey: Wipe copies of protected- and secure-keys

Although the clear-key of neither protected- nor secure-keys is
accessible, this key material should only be visible to the calling
process. So wipe all copies of protected- or secure-keys from stack,
even in case of an error.

Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Ingo Franzki <ifranzki@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/drivers/s390/crypto/pkey_api.c b/drivers/s390/crypto/pkey_api.c
index 1aa78a74fbaded85fa6e0387d6b4e52cf3487d28..ffc0b5db55c29053ce70a5ec176c4d103fa12df0 100644 (file)
--- a/drivers/s390/crypto/pkey_api.c
+++ b/drivers/s390/crypto/pkey_api.c
@@ -1359,10 +1359,9 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                rc = cca_genseckey(kgs.cardnr, kgs.domain,
                                   kgs.keytype, kgs.seckey.seckey);
                pr_debug("%s cca_genseckey()=%d\n", __func__, rc);
-               if (rc)
-                       break;
-               if (copy_to_user(ugs, &kgs, sizeof(kgs)))
-                       return -EFAULT;
+               if (!rc && copy_to_user(ugs, &kgs, sizeof(kgs)))
+                       rc = -EFAULT;
+               memzero_explicit(&kgs, sizeof(kgs));
                break;
        }
        case PKEY_CLR2SECK: {
@@ -1390,10 +1389,9 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                                     ksp.seckey.seckey, ksp.protkey.protkey,
                                     &ksp.protkey.len, &ksp.protkey.type);
                pr_debug("%s cca_sec2protkey()=%d\n", __func__, rc);
-               if (rc)
-                       break;
-               if (copy_to_user(usp, &ksp, sizeof(ksp)))
-                       return -EFAULT;
+               if (!rc && copy_to_user(usp, &ksp, sizeof(ksp)))
+                       rc = -EFAULT;
+               memzero_explicit(&ksp, sizeof(ksp));
                break;
        }
        case PKEY_CLR2PROTK: {
@@ -1437,10 +1435,9 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                rc = pkey_skey2pkey(ksp.seckey.seckey, ksp.protkey.protkey,
                                    &ksp.protkey.len, &ksp.protkey.type);
                pr_debug("%s pkey_skey2pkey()=%d\n", __func__, rc);
-               if (rc)
-                       break;
-               if (copy_to_user(usp, &ksp, sizeof(ksp)))
-                       return -EFAULT;
+               if (!rc && copy_to_user(usp, &ksp, sizeof(ksp)))
+                       rc = -EFAULT;
+               memzero_explicit(&ksp, sizeof(ksp));
                break;
        }
        case PKEY_VERIFYKEY: {
@@ -1452,10 +1449,9 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                rc = pkey_verifykey(&kvk.seckey, &kvk.cardnr, &kvk.domain,
                                    &kvk.keysize, &kvk.attributes);
                pr_debug("%s pkey_verifykey()=%d\n", __func__, rc);
-               if (rc)
-                       break;
-               if (copy_to_user(uvk, &kvk, sizeof(kvk)))
-                       return -EFAULT;
+               if (!rc && copy_to_user(uvk, &kvk, sizeof(kvk)))
+                       rc = -EFAULT;
+               memzero_explicit(&kvk, sizeof(kvk));
                break;
        }
        case PKEY_GENPROTK: {
@@ -1468,10 +1464,9 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                rc = pkey_genprotkey(kgp.keytype, kgp.protkey.protkey,
                                     &kgp.protkey.len, &kgp.protkey.type);
                pr_debug("%s pkey_genprotkey()=%d\n", __func__, rc);
-               if (rc)
-                       break;
-               if (copy_to_user(ugp, &kgp, sizeof(kgp)))
-                       return -EFAULT;
+               if (!rc && copy_to_user(ugp, &kgp, sizeof(kgp)))
+                       rc = -EFAULT;
+               memzero_explicit(&kgp, sizeof(kgp));
                break;
        }
        case PKEY_VERIFYPROTK: {
@@ -1483,6 +1478,7 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                rc = pkey_verifyprotkey(kvp.protkey.protkey,
                                        kvp.protkey.len, kvp.protkey.type);
                pr_debug("%s pkey_verifyprotkey()=%d\n", __func__, rc);
+               memzero_explicit(&kvp, sizeof(kvp));
                break;
        }
        case PKEY_KBLOB2PROTK: {
@@ -1500,10 +1496,9 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                                       &ktp.protkey.len, &ktp.protkey.type);
                pr_debug("%s pkey_keyblob2pkey()=%d\n", __func__, rc);
                kfree_sensitive(kkey);
-               if (rc)
-                       break;
-               if (copy_to_user(utp, &ktp, sizeof(ktp)))
-                       return -EFAULT;
+               if (!rc && copy_to_user(utp, &ktp, sizeof(ktp)))
+                       rc = -EFAULT;
+               memzero_explicit(&ktp, sizeof(ktp));
                break;
        }
        case PKEY_GENSECK2: {
@@ -1529,23 +1524,23 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                pr_debug("%s pkey_genseckey2()=%d\n", __func__, rc);
                kfree(apqns);
                if (rc) {
-                       kfree(kkey);
+                       kfree_sensitive(kkey);
                        break;
                }
                if (kgs.key) {
                        if (kgs.keylen < klen) {
-                               kfree(kkey);
+                               kfree_sensitive(kkey);
                                return -EINVAL;
                        }
                        if (copy_to_user(kgs.key, kkey, klen)) {
-                               kfree(kkey);
+                               kfree_sensitive(kkey);
                                return -EFAULT;
                        }
                }
                kgs.keylen = klen;
                if (copy_to_user(ugs, &kgs, sizeof(kgs)))
                        rc = -EFAULT;
-               kfree(kkey);
+               kfree_sensitive(kkey);
                break;
        }
        case PKEY_CLR2SECK2: {
@@ -1574,18 +1569,18 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                pr_debug("%s pkey_clr2seckey2()=%d\n", __func__, rc);
                kfree(apqns);
                if (rc) {
-                       kfree(kkey);
+                       kfree_sensitive(kkey);
                        memzero_explicit(&kcs, sizeof(kcs));
                        break;
                }
                if (kcs.key) {
                        if (kcs.keylen < klen) {
-                               kfree(kkey);
+                               kfree_sensitive(kkey);
                                memzero_explicit(&kcs, sizeof(kcs));
                                return -EINVAL;
                        }
                        if (copy_to_user(kcs.key, kkey, klen)) {
-                               kfree(kkey);
+                               kfree_sensitive(kkey);
                                memzero_explicit(&kcs, sizeof(kcs));
                                return -EFAULT;
                        }
@@ -1594,7 +1589,7 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                if (copy_to_user(ucs, &kcs, sizeof(kcs)))
                        rc = -EFAULT;
                memzero_explicit(&kcs, sizeof(kcs));
-               kfree(kkey);
+               kfree_sensitive(kkey);
                break;
        }
        case PKEY_VERIFYKEY2: {
@@ -1611,7 +1606,7 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                                     &kvk.cardnr, &kvk.domain,
                                     &kvk.type, &kvk.size, &kvk.flags);
                pr_debug("%s pkey_verifykey2()=%d\n", __func__, rc);
-               kfree(kkey);
+               kfree_sensitive(kkey);
                if (rc)
                        break;
                if (copy_to_user(uvk, &kvk, sizeof(kvk)))
@@ -1642,10 +1637,9 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                pr_debug("%s pkey_keyblob2pkey2()=%d\n", __func__, rc);
                kfree(apqns);
                kfree_sensitive(kkey);
-               if (rc)
-                       break;
-               if (copy_to_user(utp, &ktp, sizeof(ktp)))
-                       return -EFAULT;
+               if (!rc && copy_to_user(utp, &ktp, sizeof(ktp)))
+                       rc = -EFAULT;
+               memzero_explicit(&ktp, sizeof(ktp));
                break;
        }
        case PKEY_APQNS4K: {
@@ -1673,7 +1667,7 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                rc = pkey_apqns4key(kkey, kak.keylen, kak.flags,
                                    apqns, &nr_apqns);
                pr_debug("%s pkey_apqns4key()=%d\n", __func__, rc);
-               kfree(kkey);
+               kfree_sensitive(kkey);
                if (rc && rc != -ENOSPC) {
                        kfree(apqns);
                        break;
@@ -1759,7 +1753,7 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                protkey = kmalloc(protkeylen, GFP_KERNEL);
                if (!protkey) {
                        kfree(apqns);
-                       kfree(kkey);
+                       kfree_sensitive(kkey);
                        return -ENOMEM;
                }
                rc = pkey_keyblob2pkey3(apqns, ktp.apqn_entries,
@@ -1769,20 +1763,20 @@ static long pkey_unlocked_ioctl(struct file *filp, unsigned int cmd,
                kfree(apqns);
                kfree_sensitive(kkey);
                if (rc) {
-                       kfree(protkey);
+                       kfree_sensitive(protkey);
                        break;
                }
                if (ktp.pkey && ktp.pkeylen) {
                        if (protkeylen > ktp.pkeylen) {
-                               kfree(protkey);
+                               kfree_sensitive(protkey);
                                return -EINVAL;
                        }
                        if (copy_to_user(ktp.pkey, protkey, protkeylen)) {
-                               kfree(protkey);
+                               kfree_sensitive(protkey);
                                return -EFAULT;
                        }
                }
-               kfree(protkey);
+               kfree_sensitive(protkey);
                ktp.pkeylen = protkeylen;
                if (copy_to_user(utp, &ktp, sizeof(ktp)))
                        return -EFAULT;