Merge branch 'zcrypt-no-alloc'

Harald Freudenberger says:

====================
This series of patches has the goal to open up a do-not-allocate
memory path from the callers of the pkey in-kernel api down to
the crypto cards and back.

The asynch in-kernel cipher implementations (and the s390 PAES
cipher implementations are one of them) may be called in a
context where memory allocations which trigger IO is not acceptable.

So this patch series reworks the AP bus code, the zcrypt layer,
the pkey layer and the pkey handlers to respect this situation
by processing a new parameter xflags (execution hints flags).
There is a flag PKEY_XFLAG_NOMEMALLOC which tells the code to
not allocate memory which may lead to IO operations.

To reach this goal, the actual code changes have been differed.
The zcrypt misc functions which need memory for cprb build
use a pre allocated memory pool for this purpose. The findcard()
functions have one temp memory area preallocated and protected
with a mutex. Some smaller data is not allocated any more but went
to the stack instead. The AP bus also uses a pre-allocated
memory pool for building AP message requests.

Note that the PAES implementation still needs to get reworked
to run the protected key derivation in a real asynchronous way.
However, this rework of AP bus, zcrypt and pkey is the base work
required before reconsidering the PAES implementation.

The patch series starts bottom (AP bus) and goes up the call
chain (PKEY). At any time in the patch stack it should compile.
For easier review I tried to have one logic code change by
each patch and thus keep the patches "small".
====================

Link: https://lore.kernel.org/r/20250424133619.16495-1-freude@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

1 files changed, 26 insertions, 24 deletions

diff --git a/drivers/s390/crypto/pkey_api.c b/drivers/s390/crypto/pkey_api.c
index 3a39e167bdbf..cef60770f68b 100644
--- a/drivers/s390/crypto/pkey_api.c
+++ b/drivers/s390/crypto/pkey_api.c
@@ -24,7 +24,8 @@
  */
 static int key2protkey(const struct pkey_apqn *apqns, size_t nr_apqns,
 		       const u8 *key, size_t keylen,
-		       u8 *protkey, u32 *protkeylen, u32 *protkeytype)
+		       u8 *protkey, u32 *protkeylen, u32 *protkeytype,
+		       u32 xflags)
 {
 	int rc;
 
@@ -32,14 +33,14 @@ static int key2protkey(const struct pkey_apqn *apqns, size_t nr_apqns,
 	rc = pkey_handler_key_to_protkey(apqns, nr_apqns,
 					 key, keylen,
 					 protkey, protkeylen,
-					 protkeytype);
+					 protkeytype, xflags);
 
 	/* if this did not work, try the slowpath way */
 	if (rc == -ENODEV) {
 		rc = pkey_handler_slowpath_key_to_protkey(apqns, nr_apqns,
 							  key, keylen,
 							  protkey, protkeylen,
-							  protkeytype);
+							  protkeytype, xflags);
 		if (rc)
 			rc = -ENODEV;
 	}
@@ -52,16 +53,16 @@ static int key2protkey(const struct pkey_apqn *apqns, size_t nr_apqns,
  * In-Kernel function: Transform a key blob (of any type) into a protected key
  */
 int pkey_key2protkey(const u8 *key, u32 keylen,
-		     u8 *protkey, u32 *protkeylen, u32 *protkeytype)
+		     u8 *protkey, u32 *protkeylen, u32 *protkeytype, u32 xflags)
 {
 	int rc;
 
 	rc = key2protkey(NULL, 0, key, keylen,
-			 protkey, protkeylen, protkeytype);
+			 protkey, protkeylen, protkeytype, xflags);
 	if (rc == -ENODEV) {
 		pkey_handler_request_modules();
 		rc = key2protkey(NULL, 0, key, keylen,
-				 protkey, protkeylen, protkeytype);
+				 protkey, protkeylen, protkeytype, xflags);
 	}
 
 	return rc;
@@ -103,7 +104,7 @@ static int pkey_ioctl_genseck(struct pkey_genseck __user *ugs)
 	keybuflen = sizeof(kgs.seckey.seckey);
 	rc = pkey_handler_gen_key(&apqn, 1,
 				  kgs.keytype, PKEY_TYPE_CCA_DATA, 0, 0,
-				  kgs.seckey.seckey, &keybuflen, NULL);
+				  kgs.seckey.seckey, &keybuflen, NULL, 0);
 	pr_debug("gen_key()=%d\n", rc);
 	if (!rc && copy_to_user(ugs, &kgs, sizeof(kgs)))
 		rc = -EFAULT;
@@ -129,7 +130,7 @@ static int pkey_ioctl_clr2seck(struct pkey_clr2seck __user *ucs)
 				     kcs.keytype, PKEY_TYPE_CCA_DATA, 0, 0,
 				     kcs.clrkey.clrkey,
 				     pkey_keytype_aes_to_size(kcs.keytype),
-				     kcs.seckey.seckey, &keybuflen, NULL);
+				     kcs.seckey.seckey, &keybuflen, NULL, 0);
 	pr_debug("clr_to_key()=%d\n", rc);
 	if (!rc && copy_to_user(ucs, &kcs, sizeof(kcs)))
 		rc = -EFAULT;
@@ -154,7 +155,8 @@ static int pkey_ioctl_sec2protk(struct pkey_sec2protk __user *usp)
 					 ksp.seckey.seckey,
 					 sizeof(ksp.seckey.seckey),
 					 ksp.protkey.protkey,
-					 &ksp.protkey.len, &ksp.protkey.type);
+					 &ksp.protkey.len, &ksp.protkey.type,
+					 0);
 	pr_debug("key_to_protkey()=%d\n", rc);
 	if (!rc && copy_to_user(usp, &ksp, sizeof(ksp)))
 		rc = -EFAULT;
@@ -198,7 +200,7 @@ static int pkey_ioctl_clr2protk(struct pkey_clr2protk __user *ucp)
 	rc = key2protkey(NULL, 0,
 			 tmpbuf, sizeof(*t) + keylen,
 			 kcp.protkey.protkey,
-			 &kcp.protkey.len, &kcp.protkey.type);
+			 &kcp.protkey.len, &kcp.protkey.type, 0);
 	pr_debug("key2protkey()=%d\n", rc);
 
 	kfree_sensitive(tmpbuf);
@@ -228,12 +230,12 @@ static int pkey_ioctl_findcard(struct pkey_findcard __user *ufc)
 	rc = pkey_handler_apqns_for_key(kfc.seckey.seckey,
 					sizeof(kfc.seckey.seckey),
 					PKEY_FLAGS_MATCH_CUR_MKVP,
-					apqns, &nr_apqns);
+					apqns, &nr_apqns, 0);
 	if (rc == -ENODEV)
 		rc = pkey_handler_apqns_for_key(kfc.seckey.seckey,
 						sizeof(kfc.seckey.seckey),
 						PKEY_FLAGS_MATCH_ALT_MKVP,
-						apqns, &nr_apqns);
+						apqns, &nr_apqns, 0);
 	pr_debug("apqns_for_key()=%d\n", rc);
 	if (rc) {
 		kfree(apqns);
@@ -262,7 +264,7 @@ static int pkey_ioctl_skey2pkey(struct pkey_skey2pkey __user *usp)
 					 sizeof(ksp.seckey.seckey),
 					 ksp.protkey.protkey,
 					 &ksp.protkey.len,
-					 &ksp.protkey.type);
+					 &ksp.protkey.type, 0);
 	pr_debug("key_to_protkey()=%d\n", rc);
 	if (!rc && copy_to_user(usp, &ksp, sizeof(ksp)))
 		rc = -EFAULT;
@@ -285,7 +287,7 @@ static int pkey_ioctl_verifykey(struct pkey_verifykey __user *uvk)
 	rc = pkey_handler_verify_key(kvk.seckey.seckey,
 				     sizeof(kvk.seckey.seckey),
 				     &kvk.cardnr, &kvk.domain,
-				     &keytype, &keybitsize, &flags);
+				     &keytype, &keybitsize, &flags, 0);
 	pr_debug("verify_key()=%d\n", rc);
 	if (!rc && keytype != PKEY_TYPE_CCA_DATA)
 		rc = -EINVAL;
@@ -312,7 +314,7 @@ static int pkey_ioctl_genprotk(struct pkey_genprotk __user *ugp)
 	rc = pkey_handler_gen_key(NULL, 0, kgp.keytype,
 				  PKEY_TYPE_PROTKEY, 0, 0,
 				  kgp.protkey.protkey, &kgp.protkey.len,
-				  &kgp.protkey.type);
+				  &kgp.protkey.type, 0);
 	pr_debug("gen_key()=%d\n", rc);
 	if (!rc && copy_to_user(ugp, &kgp, sizeof(kgp)))
 		rc = -EFAULT;
@@ -354,7 +356,7 @@ static int pkey_ioctl_verifyprotk(struct pkey_verifyprotk __user *uvp)
 	memcpy(t->protkey, kvp.protkey.protkey, kvp.protkey.len);
 
 	rc = pkey_handler_verify_key(tmpbuf, sizeof(*t),
-				     NULL, NULL, NULL, NULL, NULL);
+				     NULL, NULL, NULL, NULL, NULL, 0);
 	pr_debug("verify_key()=%d\n", rc);
 
 	kfree_sensitive(tmpbuf);
@@ -377,7 +379,7 @@ static int pkey_ioctl_kblob2protk(struct pkey_kblob2pkey __user *utp)
 	ktp.protkey.len = sizeof(ktp.protkey.protkey);
 	rc = key2protkey(NULL, 0, kkey, ktp.keylen,
 			 ktp.protkey.protkey, &ktp.protkey.len,
-			 &ktp.protkey.type);
+			 &ktp.protkey.type, 0);
 	pr_debug("key2protkey()=%d\n", rc);
 	kfree_sensitive(kkey);
 	if (!rc && copy_to_user(utp, &ktp, sizeof(ktp)))
@@ -414,7 +416,7 @@ static int pkey_ioctl_genseck2(struct pkey_genseck2 __user *ugs)
 	}
 	rc = pkey_handler_gen_key(apqns, kgs.apqn_entries,
 				  u, kgs.type, kgs.size, kgs.keygenflags,
-				  kkey, &klen, NULL);
+				  kkey, &klen, NULL, 0);
 	pr_debug("gen_key()=%d\n", rc);
 	kfree(apqns);
 	if (rc) {
@@ -471,7 +473,7 @@ static int pkey_ioctl_clr2seck2(struct pkey_clr2seck2 __user *ucs)
 	rc = pkey_handler_clr_to_key(apqns, kcs.apqn_entries,
 				     u, kcs.type, kcs.size, kcs.keygenflags,
 				     kcs.clrkey.clrkey, kcs.size / 8,
-				     kkey, &klen, NULL);
+				     kkey, &klen, NULL, 0);
 	pr_debug("clr_to_key()=%d\n", rc);
 	kfree(apqns);
 	if (rc) {
@@ -514,7 +516,7 @@ static int pkey_ioctl_verifykey2(struct pkey_verifykey2 __user *uvk)
 
 	rc = pkey_handler_verify_key(kkey, kvk.keylen,
 				     &kvk.cardnr, &kvk.domain,
-				     &kvk.type, &kvk.size, &kvk.flags);
+				     &kvk.type, &kvk.size, &kvk.flags, 0);
 	pr_debug("verify_key()=%d\n", rc);
 
 	kfree_sensitive(kkey);
@@ -544,7 +546,7 @@ static int pkey_ioctl_kblob2protk2(struct pkey_kblob2pkey2 __user *utp)
 	ktp.protkey.len = sizeof(ktp.protkey.protkey);
 	rc = key2protkey(apqns, ktp.apqn_entries, kkey, ktp.keylen,
 			 ktp.protkey.protkey, &ktp.protkey.len,
-			 &ktp.protkey.type);
+			 &ktp.protkey.type, 0);
 	pr_debug("key2protkey()=%d\n", rc);
 	kfree(apqns);
 	kfree_sensitive(kkey);
@@ -579,7 +581,7 @@ static int pkey_ioctl_apqns4k(struct pkey_apqns4key __user *uak)
 		return PTR_ERR(kkey);
 	}
 	rc = pkey_handler_apqns_for_key(kkey, kak.keylen, kak.flags,
-					apqns, &nr_apqns);
+					apqns, &nr_apqns, 0);
 	pr_debug("apqns_for_key()=%d\n", rc);
 	kfree_sensitive(kkey);
 	if (rc && rc != -ENOSPC) {
@@ -626,7 +628,7 @@ static int pkey_ioctl_apqns4kt(struct pkey_apqns4keytype __user *uat)
 	}
 	rc = pkey_handler_apqns_for_keytype(kat.type,
 					    kat.cur_mkvp, kat.alt_mkvp,
-					    kat.flags, apqns, &nr_apqns);
+					    kat.flags, apqns, &nr_apqns, 0);
 	pr_debug("apqns_for_keytype()=%d\n", rc);
 	if (rc && rc != -ENOSPC) {
 		kfree(apqns);
@@ -678,7 +680,7 @@ static int pkey_ioctl_kblob2protk3(struct pkey_kblob2pkey3 __user *utp)
 		return -ENOMEM;
 	}
 	rc = key2protkey(apqns, ktp.apqn_entries, kkey, ktp.keylen,
-			 protkey, &protkeylen, &ktp.pkeytype);
+			 protkey, &protkeylen, &ktp.pkeytype, 0);
 	pr_debug("key2protkey()=%d\n", rc);
 	kfree(apqns);
 	kfree_sensitive(kkey);