sharenfs: Check for invalid characters

Check for invalid characters in sharenfs/sharesmb dataset props.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #18613

lib/libzfs/libzfs_changelist.c

@@ -177,6 +177,7 @@ changelist_postfix(prop_changelist_t *clp)
 	char shareopts[ZFS_MAXPROPLEN];
 	boolean_t commit_smb_shares = B_FALSE;
 	boolean_t commit_nfs_shares = B_FALSE;
+	int rc = 0;
 
 	/*
 	 * If CL_GATHER_DONT_UNMOUNT is set, it means we don't want to (un)mount
@@ -266,7 +267,7 @@ changelist_postfix(prop_changelist_t *clp)
 		const enum sa_protocol nfs[] =
 		    {SA_PROTOCOL_NFS, SA_NO_PROTOCOL};
 		if (sharenfs && mounted) {
-			zfs_share(cn->cn_handle, nfs);
+			rc = zfs_share(cn->cn_handle, nfs);
 			commit_nfs_shares = B_TRUE;
 		} else if (cn->cn_shared || clp->cl_waslegacy) {
 			zfs_unshare(cn->cn_handle, NULL, nfs);
@@ -275,7 +276,7 @@ changelist_postfix(prop_changelist_t *clp)
 		const enum sa_protocol smb[] =
 		    {SA_PROTOCOL_SMB, SA_NO_PROTOCOL};
 		if (sharesmb && mounted) {
-			zfs_share(cn->cn_handle, smb);
+			rc = zfs_share(cn->cn_handle, smb);
 			commit_smb_shares = B_TRUE;
 		} else if (cn->cn_shared || clp->cl_waslegacy) {
 			zfs_unshare(cn->cn_handle, NULL, smb);
@@ -291,7 +292,15 @@ changelist_postfix(prop_changelist_t *clp)
 	*p++ = SA_NO_PROTOCOL;
 	zfs_commit_shares(proto);
 
-	return (0);
+	/*
+	 * It's possible rc != 0 since we set a mountpoint or option while
+	 * SMB/NFS was not running.  This is fine, and we should not return
+	 * an error up the stack.
+	 *
+	 * At this point we only want to report mountpoint/shareops parsing
+	 * errors.
+	 */
+	return (rc == SA_SYNTAX_ERR ? rc : 0);
 }
 
 /*

lib/libzfs/libzfs_share.c

@@ -64,6 +64,10 @@ sa_enable_share(const char *zfsname, const char *mountpoint,
 {
 	VALIDATE_PROTOCOL(protocol, SA_INVALID_PROTOCOL);
 
+	int error = sa_validate_shareopts(shareopts, protocol);
+	if (error != SA_OK)
+		return (error);
+
 	const struct sa_share_impl args =
 	    init_share(zfsname, mountpoint, shareopts);
 	return (fstypes[protocol]->enable_share(&args));
@@ -111,6 +115,10 @@ sa_validate_shareopts(const char *options, enum sa_protocol protocol)
 {
 	VALIDATE_PROTOCOL(protocol, SA_INVALID_PROTOCOL);
 
+	/* error out on invalid characters */
+	if (strpbrk(options, "\a\b\f\n\r") != NULL)
+		return (SA_SYNTAX_ERR);
+
 	return (fstypes[protocol]->validate_shareopts(options));
 }