From: Sebastien Buisson <sbuisson@ddn.com>
Date: Fri, 13 May 2022 15:03:22 +0000 (+0200)
Subject: LU-15855 enc: enc-unaware clients get ENOKEY if file not found
X-Git-Tag: 2.15.51~94
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=00898697f998c095e6dab3dd27e347cb1150ee8c;p=fs%2Flustre-release.git

LU-15855 enc: enc-unaware clients get ENOKEY if file not found

To reduce issues with applications running on clients without keys
or without fscrypt support that check for the existence of a file in
an encrypted directory, return -ENOKEY instead of -ENOENT.
For encryption-unaware clients, this is done on server side in the
mdt layer, by checking if clients have the OBD_CONNECT2_ENCRYPT
connection flag.
For clients without the key, this is done in llite when the searched
filename is not in encoded form.

Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I9a3b7af3a856b7fc7222c61a308ad23168869d57
Reviewed-on: https://review.whamcloud.com/47349
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: John L. Hammond <jhammond@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
---

diff --git a/lustre/llite/crypto.c b/lustre/llite/crypto.c
index 18698d6..acd7f16 100644
--- a/lustre/llite/crypto.c
+++ b/lustre/llite/crypto.c
@@ -251,21 +251,26 @@ int ll_setup_filename(struct inode *dir, const struct qstr *iname,
 		fid->f_ver = 0;
 	}
 	rc = llcrypt_setup_filename(dir, &dname, lookup, fname);
-	if (rc == -ENOENT && lookup &&
-	    ((is_root_inode(dir) && iname->len == strlen(dot_fscrypt_name) &&
-	      strncmp(iname->name, dot_fscrypt_name, iname->len) == 0) ||
-	     (!llcrypt_has_encryption_key(dir) &&
-	      unlikely(filename_is_volatile(iname->name, iname->len, NULL))))) {
-		/* In case of subdir mount of an encrypted directory, we allow
-		 * lookup of /.fscrypt directory.
-		 */
-		/* For purpose of migration or mirroring without enc key, we
-		 * allow lookup of volatile file without enc context.
-		 */
-		memset(fname, 0, sizeof(struct llcrypt_name));
-		fname->disk_name.name = (unsigned char *)iname->name;
-		fname->disk_name.len = iname->len;
-		rc = 0;
+	if (rc == -ENOENT && lookup) {
+		if (((is_root_inode(dir) &&
+		     iname->len == strlen(dot_fscrypt_name) &&
+		     strncmp(iname->name, dot_fscrypt_name, iname->len) == 0) ||
+		     (!llcrypt_has_encryption_key(dir) &&
+		      unlikely(filename_is_volatile(iname->name,
+						    iname->len, NULL))))) {
+			/* In case of subdir mount of an encrypted directory,
+			 * we allow lookup of /.fscrypt directory.
+			 */
+			/* For purpose of migration or mirroring without enc key
+			 * we allow lookup of volatile file without enc context.
+			 */
+			memset(fname, 0, sizeof(struct llcrypt_name));
+			fname->disk_name.name = (unsigned char *)iname->name;
+			fname->disk_name.len = iname->len;
+			rc = 0;
+		} else if (!llcrypt_has_encryption_key(dir)) {
+			rc = -ENOKEY;
+		}
 	}
 	if (rc)
 		return rc;
diff --git a/lustre/mdt/mdt_handler.c b/lustre/mdt/mdt_handler.c
index 69cd0bb..8b62753 100644
--- a/lustre/mdt/mdt_handler.c
+++ b/lustre/mdt/mdt_handler.c
@@ -2396,6 +2396,15 @@ out_child:
 unlock_parent:
 	if (lhp)
 		mdt_object_unlock(info, parent, lhp, 1);
+	if (rc == -ENOENT) {
+		/* return -ENOKEY instead of -ENOENT to encryption-unaware
+		 * client if trying to access an encrypted file
+		 */
+		int rc2 = mdt_check_enc(info, parent);
+
+		if (rc2)
+			rc = rc2;
+	}
 	return rc;
 }
 
@@ -4570,13 +4579,14 @@ static int mdt_intent_getattr(enum ldlm_intent_flags it_opc,
 	rc = mdt_getattr_name_lock(info, lhc, child_bits, ldlm_rep);
 	ldlm_rep->lock_policy_res2 = clear_serious(rc);
 
-        if (mdt_get_disposition(ldlm_rep, DISP_LOOKUP_NEG))
-                ldlm_rep->lock_policy_res2 = 0;
-        if (!mdt_get_disposition(ldlm_rep, DISP_LOOKUP_POS) ||
-            ldlm_rep->lock_policy_res2) {
-                lhc->mlh_reg_lh.cookie = 0ull;
-                GOTO(out_ucred, rc = ELDLM_LOCK_ABORTED);
-        }
+	if (mdt_get_disposition(ldlm_rep, DISP_LOOKUP_NEG) &&
+	    ldlm_rep->lock_policy_res2 != -ENOKEY)
+		ldlm_rep->lock_policy_res2 = 0;
+	if (!mdt_get_disposition(ldlm_rep, DISP_LOOKUP_POS) ||
+	    ldlm_rep->lock_policy_res2) {
+		lhc->mlh_reg_lh.cookie = 0ull;
+		GOTO(out_ucred, rc = ELDLM_LOCK_ABORTED);
+	}
 
 	rc = mdt_intent_lock_replace(info, lockp, lhc, flags, rc);
         EXIT;