diff --git a/include/linux/evm.h b/include/linux/evm.h index 6d4e89b020c541216bf5b0e51d44e739e0d13e47..db5556dcdd27eb1b13faa7664263a789007ccc49 100644 --- a/include/linux/evm.h +++ b/include/linux/evm.h @@ -19,6 +19,7 @@ extern enum integrity_status evm_verifyxattr(struct dentry *dentry, void *xattr_value, size_t xattr_value_len, struct integrity_iint_cache *iint); +extern int evm_inode_setattr(struct dentry *dentry, struct iattr *attr); extern void evm_inode_post_setattr(struct dentry *dentry, int ia_valid); extern int evm_inode_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size); @@ -44,6 +45,11 @@ static inline enum integrity_status evm_verifyxattr(struct dentry *dentry, } #endif +static int evm_inode_setattr(struct dentry *dentry, struct iattr *attr) +{ + return 0; +} + static inline void evm_inode_post_setattr(struct dentry *dentry, int ia_valid) { return; diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 94d66af07aa4127cf8ee68536aef7eaef2dd874c..8fc5b5d7ceaaa77097b0cf5f14a86880ba0961c3 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -277,6 +277,21 @@ void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name) return; } +/** + * evm_inode_setattr - prevent updating an invalid EVM extended attribute + * @dentry: pointer to the affected dentry + */ +int evm_inode_setattr(struct dentry *dentry, struct iattr *attr) +{ + unsigned int ia_valid = attr->ia_valid; + enum integrity_status evm_status; + + if (ia_valid & ~(ATTR_MODE | ATTR_UID | ATTR_GID)) + return 0; + evm_status = evm_verify_current_integrity(dentry); + return evm_status == INTEGRITY_PASS ? 0 : -EPERM; +} + /** * evm_inode_post_setattr - update 'security.evm' after modifying metadata * @dentry: pointer to the affected dentry diff --git a/security/security.c b/security/security.c index 181990ae90c1e091bd20d905fc0e69fe9bcfc5b0..19251ccb2de0d09f2ed34a3e6018ffb80eb01cb2 100644 --- a/security/security.c +++ b/security/security.c @@ -571,9 +571,14 @@ int security_inode_exec_permission(struct inode *inode, unsigned int flags) int security_inode_setattr(struct dentry *dentry, struct iattr *attr) { + int ret; + if (unlikely(IS_PRIVATE(dentry->d_inode))) return 0; - return security_ops->inode_setattr(dentry, attr); + ret = security_ops->inode_setattr(dentry, attr); + if (ret) + return ret; + return evm_inode_setattr(dentry, attr); } EXPORT_SYMBOL_GPL(security_inode_setattr);