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75a323e604
Define a new structure for EVM-specific metadata, called evm_iint_cache, and embed it in the inode security blob. Introduce evm_iint_inode() to retrieve metadata, and register evm_inode_alloc_security() for the inode_alloc_security LSM hook, to initialize the structure (before splitting metadata, this task was done by iint_init_always()). Keep the non-NULL checks after calling evm_iint_inode() except in evm_inode_alloc_security(), to take into account inodes for which security_inode_alloc() was not called. When using shared metadata, obtaining a NULL pointer from integrity_iint_find() meant that the file wasn't in the IMA policy. Now, because IMA and EVM use disjoint metadata, the EVM status has to be stored for every inode regardless of the IMA policy. Given that from now on EVM relies on its own metadata, remove the iint parameter from evm_verifyxattr(). Also, directly retrieve the iint in evm_verify_hmac(), called by both evm_verifyxattr() and evm_verify_current_integrity(), since now there is no performance penalty in retrieving EVM metadata (constant time). Replicate the management of the IMA_NEW_FILE flag, by introducing evm_post_path_mknod() and evm_file_release() to respectively set and clear the newly introduced flag EVM_NEW_FILE, at the same time IMA does. Like for IMA, select CONFIG_SECURITY_PATH when EVM is enabled, to ensure that files are marked as new. Unlike ima_post_path_mknod(), evm_post_path_mknod() cannot check if a file must be appraised. Thus, it marks all affected files. Also, it does not clear EVM_NEW_FILE depending on i_version, but that is not a problem because IMA_NEW_FILE is always cleared when set in ima_check_last_writer(). Move the EVM-specific flag EVM_IMMUTABLE_DIGSIG to security/integrity/evm/evm.h, since that definition is now unnecessary in the common integrity layer. Finally, switch to the LSM reservation mechanism for the EVM xattr, and consequently decrement by one the number of xattrs to allocate in security_inode_init_security(). Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
80 lines
1.9 KiB
C
80 lines
1.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* evm.h
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*
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* Copyright (c) 2009 IBM Corporation
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* Author: Mimi Zohar <zohar@us.ibm.com>
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*/
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#ifndef _LINUX_EVM_H
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#define _LINUX_EVM_H
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#include <linux/integrity.h>
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#include <linux/xattr.h>
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#ifdef CONFIG_EVM
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extern int evm_set_key(void *key, size_t keylen);
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extern enum integrity_status evm_verifyxattr(struct dentry *dentry,
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const char *xattr_name,
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void *xattr_value,
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size_t xattr_value_len);
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int evm_inode_init_security(struct inode *inode, struct inode *dir,
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const struct qstr *qstr, struct xattr *xattrs,
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int *xattr_count);
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extern bool evm_revalidate_status(const char *xattr_name);
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extern int evm_protected_xattr_if_enabled(const char *req_xattr_name);
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extern int evm_read_protected_xattrs(struct dentry *dentry, u8 *buffer,
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int buffer_size, char type,
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bool canonical_fmt);
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#ifdef CONFIG_FS_POSIX_ACL
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extern int posix_xattr_acl(const char *xattrname);
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#else
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static inline int posix_xattr_acl(const char *xattrname)
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{
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return 0;
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}
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#endif
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#else
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static inline int evm_set_key(void *key, size_t keylen)
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{
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return -EOPNOTSUPP;
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}
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#ifdef CONFIG_INTEGRITY
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static inline enum integrity_status evm_verifyxattr(struct dentry *dentry,
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const char *xattr_name,
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void *xattr_value,
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size_t xattr_value_len)
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{
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return INTEGRITY_UNKNOWN;
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}
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#endif
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static inline int evm_inode_init_security(struct inode *inode, struct inode *dir,
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const struct qstr *qstr,
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struct xattr *xattrs,
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int *xattr_count)
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{
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return 0;
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}
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static inline bool evm_revalidate_status(const char *xattr_name)
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{
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return false;
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}
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static inline int evm_protected_xattr_if_enabled(const char *req_xattr_name)
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{
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return false;
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}
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static inline int evm_read_protected_xattrs(struct dentry *dentry, u8 *buffer,
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int buffer_size, char type,
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bool canonical_fmt)
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{
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return -EOPNOTSUPP;
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}
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#endif /* CONFIG_EVM */
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#endif /* LINUX_EVM_H */
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