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From: Roberto Sassu <roberto.sassu@huawei.com>
To: <zohar@linux.ibm.com>, <mjg59@google.com>
Cc: <linux-integrity@vger.kernel.org>,
	<linux-security-module@vger.kernel.org>,
	<linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	Roberto Sassu <roberto.sassu@huawei.com>,
	Christian Brauner <christian.brauner@ubuntu.com>,
	Andreas Gruenbacher <agruenba@redhat.com>
Subject: [PATCH v5 08/12] evm: Pass user namespace to set/remove xattr hooks
Date: Wed, 7 Apr 2021 12:52:48 +0200
Message-ID: <20210407105252.30721-9-roberto.sassu@huawei.com> (raw)
In-Reply-To: <20210407105252.30721-1-roberto.sassu@huawei.com>

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().

Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 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 e5b7bcb152b9..8cad46bcec9d 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 eab536fa260f..74f9f3a2ae53 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -340,7 +340,8 @@ 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;
@@ -398,6 +399,7 @@ static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name,
 
 /**
  * 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
@@ -409,8 +411,9 @@ static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name,
  * 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;
 
@@ -427,19 +430,21 @@ 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
@@ -447,7 +452,7 @@ 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 efb1f874dc41..7f14e59c4f8e 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1310,7 +1310,7 @@ 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,
@@ -1356,7 +1356,7 @@ 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)
-- 
2.26.2


  parent reply index

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-07 10:52 [PATCH v5 00/12] evm: Improve usability of portable signatures Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 01/12] evm: Execute evm_inode_init_security() only when an HMAC key is loaded Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 02/12] evm: Load EVM key in ima_load_x509() to avoid appraisal Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 03/12] evm: Refuse EVM_ALLOW_METADATA_WRITES only if an HMAC key is loaded Roberto Sassu
2021-04-30 20:28   ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 04/12] ima: Move ima_reset_appraise_flags() call to post hooks Roberto Sassu
2021-04-07 16:17   ` Casey Schaufler
2021-04-07 16:31     ` Roberto Sassu
2021-04-26 19:49     ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 05/12] evm: Introduce evm_status_revalidate() Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 06/12] evm: Ignore INTEGRITY_NOLABEL/INTEGRITY_NOXATTRS if conditions are safe Roberto Sassu
2021-05-03  0:12   ` Mimi Zohar
2021-05-03  7:55     ` Roberto Sassu
2021-05-03 12:07       ` Mimi Zohar
2021-05-03 14:15       ` Roberto Sassu
2021-05-03 14:34         ` Mimi Zohar
2021-05-04 13:16           ` Roberto Sassu
2021-05-04 13:45             ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 07/12] evm: Allow xattr/attr operations for portable signatures Roberto Sassu
2021-05-03  0:12   ` Mimi Zohar
2021-05-04 14:28     ` Roberto Sassu
2021-05-04 14:49       ` Mimi Zohar
2021-04-07 10:52 ` Roberto Sassu [this message]
2021-04-07 12:06   ` [PATCH v5 08/12] evm: Pass user namespace to set/remove xattr hooks Christian Brauner
2021-04-07 10:52 ` [PATCH v5 09/12] evm: Allow setxattr() and setattr() for unmodified metadata Roberto Sassu
2021-04-07 12:05   ` Christian Brauner
2021-04-07 15:23   ` kernel test robot
2021-04-07 18:14   ` kernel test robot
2021-04-07 19:28     ` [RESEND][PATCH " Roberto Sassu
2021-05-03 13:00   ` [PATCH " Mimi Zohar
2021-05-03 14:48     ` Roberto Sassu
2021-05-03 15:13       ` Mimi Zohar
2021-05-03 15:30         ` Roberto Sassu
2021-05-03 15:11     ` Roberto Sassu
2021-05-03 15:26       ` Mimi Zohar
2021-05-03 15:32         ` Roberto Sassu
2021-05-03 15:48           ` Mimi Zohar
2021-04-07 10:52 ` [PATCH v5 10/12] ima: Allow imasig requirement to be satisfied by EVM portable signatures Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 11/12] ima: Introduce template field evmsig and write to field sig as fallback Roberto Sassu
2021-04-07 10:52 ` [PATCH v5 12/12] ima: Don't remove security.ima if file must not be appraised Roberto Sassu

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