Merge tag 'integrity-v6.10' of ssh://ra.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull integrity updates from Mimi Zohar:
 "Two IMA changes, one EVM change, a use after free bug fix, and a code
  cleanup to address "-Wflex-array-member-not-at-end" warnings:

   - The existing IMA {ascii, binary}_runtime_measurements lists include
     a hard coded SHA1 hash. To address this limitation, define per TPM
     enabled hash algorithm {ascii, binary}_runtime_measurements lists

   - Close an IMA integrity init_module syscall measurement gap by
     defining a new critical-data record

   - Enable (partial) EVM support on stacked filesystems (overlayfs).
     Only EVM portable & immutable file signatures are copied up, since
     they do not contain filesystem specific metadata"

* tag 'integrity-v6.10' of ssh://ra.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: add crypto agility support for template-hash algorithm
  evm: Rename is_unsupported_fs to is_unsupported_hmac_fs
  fs: Rename SB_I_EVM_UNSUPPORTED to SB_I_EVM_HMAC_UNSUPPORTED
  evm: Enforce signatures on unsupported filesystem for EVM_INIT_X509
  ima: re-evaluate file integrity on file metadata change
  evm: Store and detect metadata inode attributes changes
  ima: Move file-change detection variables into new structure
  evm: Use the metadata inode to calculate metadata hash
  evm: Implement per signature type decision in security_inode_copy_up_xattr
  security: allow finer granularity in permitting copy-up of security xattrs
  ima: Rename backing_inode to real_inode
  integrity: Avoid -Wflex-array-member-not-at-end warnings
  ima: define an init_module critical data record
  ima: Fix use-after-free on a dentry's dname.name

Author: torvalds

fs/overlayfs/copy_up.c

@@ -114,7 +114,7 @@ int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct de
 		if (ovl_is_private_xattr(sb, name))
 			continue;
 
-		error = security_inode_copy_up_xattr(name);
+		error = security_inode_copy_up_xattr(old, name);
 		if (error < 0 && error != -EOPNOTSUPP)
 			break;
 		if (error == 1) {

fs/overlayfs/super.c

@@ -1460,7 +1460,7 @@ 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;
+	sb->s_iflags |= SB_I_EVM_HMAC_UNSUPPORTED;
 
 	err = -ENOMEM;
 	root_dentry = ovl_get_root(sb, ctx->upper.dentry, oe);

include/linux/evm.h

@@ -26,6 +26,8 @@ extern int evm_protected_xattr_if_enabled(const char *req_xattr_name);
 extern int evm_read_protected_xattrs(struct dentry *dentry, u8 *buffer,
 				     int buffer_size, char type,
 				     bool canonical_fmt);
+extern bool evm_metadata_changed(struct inode *inode,
+				 struct inode *metadata_inode);
 #ifdef CONFIG_FS_POSIX_ACL
 extern int posix_xattr_acl(const char *xattrname);
 #else
@@ -76,5 +78,11 @@ static inline int evm_read_protected_xattrs(struct dentry *dentry, u8 *buffer,
 	return -EOPNOTSUPP;
 }
 
+static inline bool evm_metadata_changed(struct inode *inode,
+					struct inode *metadata_inode)
+{
+	return false;
+}
+
 #endif /* CONFIG_EVM */
 #endif /* LINUX_EVM_H */

include/linux/fs.h

@@ -1174,7 +1174,7 @@ 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_EVM_HMAC_UNSUPPORTED	0x00000080
 
 #define SB_I_SKIP_SYNC	0x00000100	/* Skip superblock at global sync */
 #define SB_I_PERSB_BDI	0x00000200	/* has a per-sb bdi */

include/linux/integrity.h

@@ -8,6 +8,7 @@
 #define _LINUX_INTEGRITY_H
 
 #include <linux/fs.h>
+#include <linux/iversion.h>
 
 enum integrity_status {
 	INTEGRITY_PASS = 0,
@@ -28,4 +29,37 @@ static inline void integrity_load_keys(void)
 }
 #endif /* CONFIG_INTEGRITY */
 
+/* An inode's attributes for detection of changes */
+struct integrity_inode_attributes {
+	u64 version;		/* track inode changes */
+	unsigned long ino;
+	dev_t dev;
+};
+
+/*
+ * On stacked filesystems the i_version alone is not enough to detect file data
+ * or metadata change. Additional metadata is required.
+ */
+static inline void
+integrity_inode_attrs_store(struct integrity_inode_attributes *attrs,
+			    u64 i_version, const struct inode *inode)
+{
+	attrs->version = i_version;
+	attrs->dev = inode->i_sb->s_dev;
+	attrs->ino = inode->i_ino;
+}
+
+/*
+ * On stacked filesystems detect whether the inode or its content has changed.
+ */
+static inline bool
+integrity_inode_attrs_changed(const struct integrity_inode_attributes *attrs,
+			      const struct inode *inode)
+{
+	return (inode->i_sb->s_dev != attrs->dev ||
+		inode->i_ino != attrs->ino ||
+		!inode_eq_iversion(inode, attrs->version));
+}
+
+
 #endif /* _LINUX_INTEGRITY_H */

include/linux/lsm_hook_defs.h

@@ -176,7 +176,8 @@ LSM_HOOK(int, 0, inode_listsecurity, struct inode *inode, char *buffer,
 	 size_t buffer_size)
 LSM_HOOK(void, LSM_RET_VOID, inode_getsecid, struct inode *inode, u32 *secid)
 LSM_HOOK(int, 0, inode_copy_up, struct dentry *src, struct cred **new)
-LSM_HOOK(int, -EOPNOTSUPP, inode_copy_up_xattr, const char *name)
+LSM_HOOK(int, -EOPNOTSUPP, inode_copy_up_xattr, struct dentry *src,
+	 const char *name)
 LSM_HOOK(int, 0, kernfs_init_security, struct kernfs_node *kn_dir,
 	 struct kernfs_node *kn)
 LSM_HOOK(int, 0, file_permission, struct file *file, int mask)

include/linux/security.h

@@ -398,7 +398,7 @@ int security_inode_setsecurity(struct inode *inode, const char *name, const void
 int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);
 void security_inode_getsecid(struct inode *inode, u32 *secid);
 int security_inode_copy_up(struct dentry *src, struct cred **new);
-int security_inode_copy_up_xattr(const char *name);
+int security_inode_copy_up_xattr(struct dentry *src, const char *name);
 int security_kernfs_init_security(struct kernfs_node *kn_dir,
 				  struct kernfs_node *kn);
 int security_file_permission(struct file *file, int mask);
@@ -1016,7 +1016,7 @@ static inline int security_kernfs_init_security(struct kernfs_node *kn_dir,
 	return 0;
 }
 
-static inline int security_inode_copy_up_xattr(const char *name)
+static inline int security_inode_copy_up_xattr(struct dentry *src, const char *name)
 {
 	return -EOPNOTSUPP;
 }

security/integrity/evm/evm.h

@@ -39,6 +39,7 @@ struct xattr_list {
 struct evm_iint_cache {
 	unsigned long flags;
 	enum integrity_status evm_status:4;
+	struct integrity_inode_attributes metadata_inode;
 };
 
 extern struct lsm_blob_sizes evm_blob_sizes;
@@ -61,7 +62,7 @@ extern int evm_hmac_attrs;
 extern struct list_head evm_config_xattrnames;
 
 struct evm_digest {
-	struct ima_digest_data hdr;
+	struct ima_digest_data_hdr hdr;
 	char digest[IMA_MAX_DIGEST_SIZE];
 } __packed;
 
@@ -74,11 +75,12 @@ int evm_update_evmxattr(struct dentry *dentry,
 			size_t req_xattr_value_len);
 int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name,
 		  const char *req_xattr_value,
-		  size_t req_xattr_value_len, struct evm_digest *data);
+		  size_t req_xattr_value_len, struct evm_digest *data,
+		  struct evm_iint_cache *iint);
 int evm_calc_hash(struct dentry *dentry, const char *req_xattr_name,
 		  const char *req_xattr_value,
 		  size_t req_xattr_value_len, char type,
-		  struct evm_digest *data);
+		  struct evm_digest *data, struct evm_iint_cache *iint);
 int evm_init_hmac(struct inode *inode, const struct xattr *xattrs,
 		  char *hmac_val);
 int evm_init_secfs(void);

security/integrity/evm/evm_crypto.c

@@ -221,16 +221,18 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
 				 const char *req_xattr_name,
 				 const char *req_xattr_value,
 				 size_t req_xattr_value_len,
-				 uint8_t type, struct evm_digest *data)
+				 uint8_t type, struct evm_digest *data,
+				 struct evm_iint_cache *iint)
 {
-	struct inode *inode = d_backing_inode(dentry);
+	struct inode *inode = d_inode(d_real(dentry, D_REAL_METADATA));
 	struct xattr_list *xattr;
 	struct shash_desc *desc;
 	size_t xattr_size = 0;
 	char *xattr_value = NULL;
 	int error;
 	int size, user_space_size;
 	bool ima_present = false;
+	u64 i_version = 0;
 
 	if (!(inode->i_opflags & IOP_XATTR) ||
 	    inode->i_sb->s_user_ns != &init_user_ns)
@@ -294,6 +296,13 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
 	}
 	hmac_add_misc(desc, inode, type, data->digest);
 
+	if (inode != d_backing_inode(dentry) && iint) {
+		if (IS_I_VERSION(inode))
+			i_version = inode_query_iversion(inode);
+		integrity_inode_attrs_store(&iint->metadata_inode, i_version,
+					    inode);
+	}
+
 	/* Portable EVM signatures must include an IMA hash */
 	if (type == EVM_XATTR_PORTABLE_DIGSIG && !ima_present)
 		error = -EPERM;
@@ -305,18 +314,19 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
 
 int evm_calc_hmac(struct dentry *dentry, const char *req_xattr_name,
 		  const char *req_xattr_value, size_t req_xattr_value_len,
-		  struct evm_digest *data)
+		  struct evm_digest *data, struct evm_iint_cache *iint)
 {
 	return evm_calc_hmac_or_hash(dentry, req_xattr_name, req_xattr_value,
-				    req_xattr_value_len, EVM_XATTR_HMAC, data);
+				    req_xattr_value_len, EVM_XATTR_HMAC, data,
+				    iint);
 }
 
 int evm_calc_hash(struct dentry *dentry, const char *req_xattr_name,
 		  const char *req_xattr_value, size_t req_xattr_value_len,
-		  char type, struct evm_digest *data)
+		  char type, struct evm_digest *data, struct evm_iint_cache *iint)
 {
 	return evm_calc_hmac_or_hash(dentry, req_xattr_name, req_xattr_value,
-				     req_xattr_value_len, type, data);
+				     req_xattr_value_len, type, data, iint);
 }
 
 static int evm_is_immutable(struct dentry *dentry, struct inode *inode)
@@ -357,6 +367,7 @@ int evm_update_evmxattr(struct dentry *dentry, const char *xattr_name,
 			const char *xattr_value, size_t xattr_value_len)
 {
 	struct inode *inode = d_backing_inode(dentry);
+	struct evm_iint_cache *iint = evm_iint_inode(inode);
 	struct evm_digest data;
 	int rc = 0;
 
@@ -372,7 +383,7 @@ int evm_update_evmxattr(struct dentry *dentry, const char *xattr_name,
 
 	data.hdr.algo = HASH_ALGO_SHA1;
 	rc = evm_calc_hmac(dentry, xattr_name, xattr_value,
-			   xattr_value_len, &data);
+			   xattr_value_len, &data, iint);
 	if (rc == 0) {
 		data.hdr.xattr.sha1.type = EVM_XATTR_HMAC;
 		rc = __vfs_setxattr_noperm(&nop_mnt_idmap, dentry,