Merge tag 'integrity-v6.8' of git://git.kernel.org/pub/scm/linux/kern…

…el/git/zohar/linux-integrity

Pull integrity updates from Mimi Zohar:

 - Add a new IMA/EVM maintainer and reviewer

 - Disable EVM on overlayfs

   The EVM HMAC and the original file signatures contain filesystem
   specific metadata (e.g. i_ino, i_generation and s_uuid), preventing
   the security.evm xattr from directly being copied up to the overlay.
   Further before calculating and writing out the overlay file's EVM
   HMAC, EVM must first verify the existing backing file's
   'security.evm' value.

   For now until a solution is developed, disable EVM on overlayfs.

 - One bug fix and two cleanups

* tag 'integrity-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  overlay: disable EVM
  evm: add support to disable EVM on unsupported filesystems
  evm: don't copy up 'security.evm' xattr
  MAINTAINERS: Add Eric Snowberg as a reviewer to IMA
  MAINTAINERS: Add Roberto Sassu as co-maintainer to IMA and EVM
  KEYS: encrypted: Add check for strsep
  ima: Remove EXPERIMENTAL from Kconfig
  ima: Reword IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY

MAINTAINERS

@@ -7930,6 +7930,7 @@ F:	include/uapi/linux/ext4.h
 
 Extended Verification Module (EVM)
 M:	Mimi Zohar <[email protected]>
+M:	Roberto Sassu <[email protected]>
 L:	[email protected]
 S:	Supported
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git
@@ -10518,7 +10519,9 @@ F:	drivers/crypto/inside-secure/
 
 INTEGRITY MEASUREMENT ARCHITECTURE (IMA)
 M:	Mimi Zohar <[email protected]>
+M:	Roberto Sassu <[email protected]>
 M:	Dmitry Kasatkin <[email protected]>
+R:	Eric Snowberg <[email protected]>
 L:	[email protected]
 S:	Supported
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git

fs/overlayfs/super.c

@@ -1454,6 +1454,7 @@ int ovl_fill_super(struct super_block *sb, struct fs_context *fc)
 	 * lead to unexpected results.
 	 */
 	sb->s_iflags |= SB_I_NOUMASK;
+	sb->s_iflags |= SB_I_EVM_UNSUPPORTED;
 
 	err = -ENOMEM;
 	root_dentry = ovl_get_root(sb, ctx->upper.dentry, oe);

include/linux/evm.h

@@ -31,6 +31,7 @@ extern void evm_inode_post_setxattr(struct dentry *dentry,
 				    const char *xattr_name,
 				    const void *xattr_value,
 				    size_t xattr_value_len);
+extern int evm_inode_copy_up_xattr(const char *name);
 extern int evm_inode_removexattr(struct mnt_idmap *idmap,
 				 struct dentry *dentry, const char *xattr_name);
 extern void evm_inode_post_removexattr(struct dentry *dentry,
@@ -117,6 +118,11 @@ static inline void evm_inode_post_setxattr(struct dentry *dentry,
 	return;
 }
 
+static inline int  evm_inode_copy_up_xattr(const char *name)
+{
+	return 0;
+}
+
 static inline int evm_inode_removexattr(struct mnt_idmap *idmap,
 					struct dentry *dentry,
 					const char *xattr_name)

include/linux/fs.h

@@ -1166,6 +1166,7 @@ extern int send_sigurg(struct fown_struct *fown);
 #define SB_I_USERNS_VISIBLE		0x00000010 /* fstype already mounted */
 #define SB_I_IMA_UNVERIFIABLE_SIGNATURE	0x00000020
 #define SB_I_UNTRUSTED_MOUNTER		0x00000040
+#define SB_I_EVM_UNSUPPORTED		0x00000080
 
 #define SB_I_SKIP_SYNC	0x00000100	/* Skip superblock at global sync */
 #define SB_I_PERSB_BDI	0x00000200	/* has a per-sb bdi */

security/integrity/evm/evm_main.c

@@ -151,6 +151,17 @@ static int evm_find_protected_xattrs(struct dentry *dentry)
 	return count;
 }
 
+static int is_unsupported_fs(struct dentry *dentry)
+{
+	struct inode *inode = d_backing_inode(dentry);
+
+	if (inode->i_sb->s_iflags & SB_I_EVM_UNSUPPORTED) {
+		pr_info_once("%s not supported\n", inode->i_sb->s_type->name);
+		return 1;
+	}
+	return 0;
+}
+
 /*
  * evm_verify_hmac - calculate and compare the HMAC with the EVM xattr
  *
@@ -181,6 +192,9 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
 		     iint->evm_status == INTEGRITY_PASS_IMMUTABLE))
 		return iint->evm_status;
 
+	if (is_unsupported_fs(dentry))
+		return INTEGRITY_UNKNOWN;
+
 	/* if status is not PASS, try to check again - against -ENOMEM */
 
 	/* first need to know the sig type */
@@ -408,6 +422,9 @@ enum integrity_status evm_verifyxattr(struct dentry *dentry,
 	if (!evm_key_loaded() || !evm_protected_xattr(xattr_name))
 		return INTEGRITY_UNKNOWN;
 
+	if (is_unsupported_fs(dentry))
+		return INTEGRITY_UNKNOWN;
+
 	if (!iint) {
 		iint = integrity_iint_find(d_backing_inode(dentry));
 		if (!iint)
@@ -491,15 +508,21 @@ static int evm_protect_xattr(struct mnt_idmap *idmap,
 	if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) {
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
+		if (is_unsupported_fs(dentry))
+			return -EPERM;
 	} else if (!evm_protected_xattr(xattr_name)) {
 		if (!posix_xattr_acl(xattr_name))
 			return 0;
+		if (is_unsupported_fs(dentry))
+			return 0;
+
 		evm_status = evm_verify_current_integrity(dentry);
 		if ((evm_status == INTEGRITY_PASS) ||
 		    (evm_status == INTEGRITY_NOXATTRS))
 			return 0;
 		goto out;
-	}
+	} else if (is_unsupported_fs(dentry))
+		return 0;
 
 	evm_status = evm_verify_current_integrity(dentry);
 	if (evm_status == INTEGRITY_NOXATTRS) {
@@ -750,6 +773,9 @@ void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name,
 	if (!(evm_initialized & EVM_INIT_HMAC))
 		return;
 
+	if (is_unsupported_fs(dentry))
+		return;
+
 	evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len);
 }
 
@@ -814,8 +840,12 @@ int evm_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	if (evm_initialized & EVM_ALLOW_METADATA_WRITES)
 		return 0;
 
+	if (is_unsupported_fs(dentry))
+		return 0;
+
 	if (!(ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)))
 		return 0;
+
 	evm_status = evm_verify_current_integrity(dentry);
 	/*
 	 * Writing attrs is safe for portable signatures, as portable signatures
@@ -859,10 +889,20 @@ void evm_inode_post_setattr(struct dentry *dentry, int ia_valid)
 	if (!(evm_initialized & EVM_INIT_HMAC))
 		return;
 
+	if (is_unsupported_fs(dentry))
+		return;
+
 	if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
 		evm_update_evmxattr(dentry, NULL, NULL, 0);
 }
 
+int evm_inode_copy_up_xattr(const char *name)
+{
+	if (strcmp(name, XATTR_NAME_EVM) == 0)
+		return 1; /* Discard */
+	return -EOPNOTSUPP;
+}
+
 /*
  * evm_inode_init_security - initializes security.evm HMAC value
  */

security/integrity/ima/Kconfig

@@ -243,22 +243,22 @@ config IMA_APPRAISE_MODSIG
 	   to accept such signatures.
 
 config IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
-	bool "Permit keys validly signed by a built-in or secondary CA cert (EXPERIMENTAL)"
+	bool "Permit keys validly signed by a built-in, machine (if configured) or secondary"
 	depends on SYSTEM_TRUSTED_KEYRING
 	depends on SECONDARY_TRUSTED_KEYRING
 	depends on INTEGRITY_ASYMMETRIC_KEYS
 	select INTEGRITY_TRUSTED_KEYRING
 	default n
 	help
 	  Keys may be added to the IMA or IMA blacklist keyrings, if the
-	  key is validly signed by a CA cert in the system built-in or
-	  secondary trusted keyrings. The key must also have the
-	  digitalSignature usage set.
+	  key is validly signed by a CA cert in the system built-in,
+	  machine (if configured), or secondary trusted keyrings. The
+	  key must also have the digitalSignature usage set.
 
 	  Intermediate keys between those the kernel has compiled in and the
 	  IMA keys to be added may be added to the system secondary keyring,
 	  provided they are validly signed by a key already resident in the
-	  built-in or secondary trusted keyrings.
+	  built-in, machine (if configured) or secondary trusted keyrings.
 
 config IMA_BLACKLIST_KEYRING
 	bool "Create IMA machine owner blacklist keyrings (EXPERIMENTAL)"

security/keys/encrypted-keys/encrypted.c

@@ -237,6 +237,10 @@ static int datablob_parse(char *datablob, const char **format,
 			break;
 		}
 		*decrypted_data = strsep(&datablob, " \t");
+		if (!*decrypted_data) {
+			pr_info("encrypted_key: decrypted_data is missing\n");
+			break;
+		}
 		ret = 0;
 		break;
 	case Opt_load:

security/security.c

@@ -2623,7 +2623,7 @@ int security_inode_copy_up_xattr(const char *name)
 			return rc;
 	}
 
-	return LSM_RET_DEFAULT(inode_copy_up_xattr);
+	return evm_inode_copy_up_xattr(name);
 }
 EXPORT_SYMBOL(security_inode_copy_up_xattr);