From 7e135dc725417ecc0629afb4b3b24457d2a4869d Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Fri, 14 May 2021 17:27:48 +0200 Subject: [PATCH] evm: Pass user namespace to set/remove xattr hooks In preparation for 'evm: Allow setxattr() and setattr() for unmodified metadata', this patch passes mnt_userns to the inode set/remove xattr hooks so that the GID of the inode on an idmapped mount is correctly determined by posix_acl_update_mode(). Signed-off-by: Roberto Sassu Reviewed-by: Christian Brauner Cc: Andreas Gruenbacher Signed-off-by: Mimi Zohar --- include/linux/evm.h | 12 ++++++++---- security/integrity/evm/evm_main.c | 17 +++++++++++------ security/security.c | 4 ++-- 3 files changed, 21 insertions(+), 12 deletions(-) diff --git a/include/linux/evm.h b/include/linux/evm.h index 39bb17a8236b..31ef1dbbb3ac 100644 --- a/include/linux/evm.h +++ b/include/linux/evm.h @@ -23,13 +23,15 @@ extern enum integrity_status evm_verifyxattr(struct dentry *dentry, 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, +extern int evm_inode_setxattr(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *name, const void *value, size_t size); 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_removexattr(struct dentry *dentry, const char *xattr_name); +extern int evm_inode_removexattr(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *xattr_name); extern void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name); extern int evm_inode_init_security(struct inode *inode, @@ -72,7 +74,8 @@ static inline void evm_inode_post_setattr(struct dentry *dentry, int ia_valid) return; } -static inline int evm_inode_setxattr(struct dentry *dentry, const char *name, +static inline int evm_inode_setxattr(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *name, const void *value, size_t size) { return 0; @@ -86,7 +89,8 @@ static inline void evm_inode_post_setxattr(struct dentry *dentry, return; } -static inline int evm_inode_removexattr(struct dentry *dentry, +static inline int evm_inode_removexattr(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *xattr_name) { return 0; diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 333524e879b5..300df6906e05 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -342,7 +342,8 @@ static enum integrity_status evm_verify_current_integrity(struct dentry *dentry) * For posix xattr acls only, permit security.evm, even if it currently * doesn't exist, to be updated unless the EVM signature is immutable. */ -static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name, +static int evm_protect_xattr(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *xattr_name, const void *xattr_value, size_t xattr_value_len) { enum integrity_status evm_status; @@ -406,6 +407,7 @@ out: /** * evm_inode_setxattr - protect the EVM extended attribute + * @mnt_userns: user namespace of the idmapped mount * @dentry: pointer to the affected dentry * @xattr_name: pointer to the affected extended attribute name * @xattr_value: pointer to the new extended attribute value @@ -417,8 +419,9 @@ out: * userspace from writing HMAC value. Writing 'security.evm' requires * requires CAP_SYS_ADMIN privileges. */ -int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name, - const void *xattr_value, size_t xattr_value_len) +int evm_inode_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, + const char *xattr_name, const void *xattr_value, + size_t xattr_value_len) { const struct evm_ima_xattr_data *xattr_data = xattr_value; @@ -435,19 +438,21 @@ int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name, xattr_data->type != EVM_XATTR_PORTABLE_DIGSIG) return -EPERM; } - return evm_protect_xattr(dentry, xattr_name, xattr_value, + return evm_protect_xattr(mnt_userns, dentry, xattr_name, xattr_value, xattr_value_len); } /** * evm_inode_removexattr - protect the EVM extended attribute + * @mnt_userns: user namespace of the idmapped mount * @dentry: pointer to the affected dentry * @xattr_name: pointer to the affected extended attribute name * * Removing 'security.evm' requires CAP_SYS_ADMIN privileges and that * the current value is valid. */ -int evm_inode_removexattr(struct dentry *dentry, const char *xattr_name) +int evm_inode_removexattr(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *xattr_name) { /* Policy permits modification of the protected xattrs even though * there's no HMAC key loaded @@ -455,7 +460,7 @@ int evm_inode_removexattr(struct dentry *dentry, const char *xattr_name) if (evm_initialized & EVM_ALLOW_METADATA_WRITES) return 0; - return evm_protect_xattr(dentry, xattr_name, NULL, 0); + return evm_protect_xattr(mnt_userns, dentry, xattr_name, NULL, 0); } static void evm_reset_status(struct inode *inode) diff --git a/security/security.c b/security/security.c index b38155b2de83..e9f8010a2341 100644 --- a/security/security.c +++ b/security/security.c @@ -1354,7 +1354,7 @@ int security_inode_setxattr(struct user_namespace *mnt_userns, ret = ima_inode_setxattr(dentry, name, value, size); if (ret) return ret; - return evm_inode_setxattr(dentry, name, value, size); + return evm_inode_setxattr(mnt_userns, dentry, name, value, size); } void security_inode_post_setxattr(struct dentry *dentry, const char *name, @@ -1399,7 +1399,7 @@ int security_inode_removexattr(struct user_namespace *mnt_userns, ret = ima_inode_removexattr(dentry, name); if (ret) return ret; - return evm_inode_removexattr(dentry, name); + return evm_inode_removexattr(mnt_userns, dentry, name); } int security_inode_need_killpriv(struct dentry *dentry) -- 2.11.0