From: Stefan Berger <stefanb@linux.ibm.com>
To: linux-integrity@vger.kernel.org
Cc: zohar@linux.ibm.com, serge@hallyn.com,
christian.brauner@ubuntu.com, containers@lists.linux.dev,
dmitry.kasatkin@gmail.com, ebiederm@xmission.com,
krzysztof.struczynski@huawei.com, roberto.sassu@huawei.com,
mpeters@redhat.com, lhinds@redhat.com, lsturman@redhat.com,
puiterwi@redhat.com, jejb@linux.ibm.com, jamjoom@us.ibm.com,
linux-kernel@vger.kernel.org, paul@paul-moore.com,
rgb@redhat.com, linux-security-module@vger.kernel.org,
jmorris@namei.org, Stefan Berger <stefanb@linux.ibm.com>,
Denis Semakin <denis.semakin@huawei.com>
Subject: [PATCH v11 12/27] ima: Define mac_admin_ns_capable() as a wrapper for ns_capable()
Date: Wed, 2 Mar 2022 08:46:47 -0500 [thread overview]
Message-ID: <20220302134703.1273041-13-stefanb@linux.ibm.com> (raw)
In-Reply-To: <20220302134703.1273041-1-stefanb@linux.ibm.com>
Define mac_admin_ns_capable() as a wrapper for the combined ns_capable()
checks on CAP_MAC_ADMIN and CAP_SYS_ADMIN in a user namespace. Return
true on the check if either capability or both are available.
Use mac_admin_ns_capable() in place of capable(SYS_ADMIN). This will allow
an IMA namespace to read the policy with only CAP_MAC_ADMIN, which has
less privileges than CAP_SYS_ADMIN.
Since CAP_MAC_ADMIN is an additional capability added to an existing gate
avoid auditing in case it is not set.
Signed-off-by: Denis Semakin <denis.semakin@huawei.com>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
v11:
- use ns_capable_noaudit for CAP_MAC_ADMIN to avoid auditing in this case
---
include/linux/capability.h | 6 ++++++
security/integrity/ima/ima.h | 6 ++++++
security/integrity/ima/ima_fs.c | 5 ++++-
3 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/include/linux/capability.h b/include/linux/capability.h
index 65efb74c3585..dc3e1230b365 100644
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -270,6 +270,12 @@ static inline bool checkpoint_restore_ns_capable(struct user_namespace *ns)
ns_capable(ns, CAP_SYS_ADMIN);
}
+static inline bool mac_admin_ns_capable(struct user_namespace *ns)
+{
+ return ns_capable_noaudit(ns, CAP_MAC_ADMIN) ||
+ ns_capable(ns, CAP_SYS_ADMIN);
+}
+
/* audit system wants to get cap info from files as well */
int get_vfs_caps_from_disk(struct user_namespace *mnt_userns,
const struct dentry *dentry,
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 5bf7f080c2be..626a6ce2453c 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -491,4 +491,10 @@ static inline int ima_filter_rule_match(u32 secid, u32 field, u32 op,
#define POLICY_FILE_FLAGS S_IWUSR
#endif /* CONFIG_IMA_READ_POLICY */
+static inline
+struct user_namespace *ima_user_ns_from_file(const struct file *filp)
+{
+ return file_inode(filp)->i_sb->s_user_ns;
+}
+
#endif /* __LINUX_IMA_H */
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 89d3113ceda1..c41aa61b7393 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -377,6 +377,9 @@ static const struct seq_operations ima_policy_seqops = {
*/
static int ima_open_policy(struct inode *inode, struct file *filp)
{
+#ifdef CONFIG_IMA_READ_POLICY
+ struct user_namespace *user_ns = ima_user_ns_from_file(filp);
+#endif
struct ima_namespace *ns = &init_ima_ns;
if (!(filp->f_flags & O_WRONLY)) {
@@ -385,7 +388,7 @@ static int ima_open_policy(struct inode *inode, struct file *filp)
#else
if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
return -EACCES;
- if (!capable(CAP_SYS_ADMIN))
+ if (!mac_admin_ns_capable(user_ns))
return -EPERM;
return seq_open(filp, &ima_policy_seqops);
#endif
--
2.31.1
next prev parent reply other threads:[~2022-03-02 13:50 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-02 13:46 [PATCH v11 00/27] ima: Namespace IMA with audit support in IMA-ns Stefan Berger
2022-03-02 13:46 ` [PATCH v11 01/27] ima: Return error code obtained from securityfs functions Stefan Berger
2022-03-02 13:46 ` [PATCH v11 02/27] securityfs: rework dentry creation Stefan Berger
2022-03-02 13:46 ` [PATCH v11 03/27] securityfs: Extend securityfs with namespacing support Stefan Berger
2022-03-02 13:46 ` [PATCH v11 04/27] ima: Define ima_namespace struct and start moving variables into it Stefan Berger
2022-03-02 13:46 ` [PATCH v11 05/27] ima: Move arch_policy_entry into ima_namespace Stefan Berger
2022-03-02 13:46 ` [PATCH v11 06/27] ima: Move ima_htable " Stefan Berger
2022-03-02 13:46 ` [PATCH v11 07/27] ima: Move measurement list related variables " Stefan Berger
2022-03-02 13:46 ` [PATCH v11 08/27] ima: Move some IMA policy and filesystem " Stefan Berger
2022-03-02 13:46 ` [PATCH v11 09/27] ima: Move IMA securityfs files into ima_namespace or onto stack Stefan Berger
2022-03-02 13:46 ` [PATCH v11 10/27] ima: Move ima_lsm_policy_notifier into ima_namespace Stefan Berger
2022-03-02 13:46 ` [PATCH v11 11/27] ima: Switch to lazy lsm policy updates for better performance Stefan Berger
2022-03-02 13:46 ` Stefan Berger [this message]
2022-03-02 13:46 ` [PATCH v11 13/27] ima: Only accept AUDIT rules for non-init_ima_ns namespaces for now Stefan Berger
2022-03-02 13:46 ` [PATCH v11 14/27] userns: Add pointer to ima_namespace to user_namespace Stefan Berger
2022-03-02 13:46 ` [PATCH v11 15/27] ima: Implement hierarchical processing of file accesses Stefan Berger
2022-03-02 13:46 ` [PATCH v11 16/27] ima: Implement ima_free_policy_rules() for freeing of an ima_namespace Stefan Berger
2022-03-02 13:46 ` [PATCH v11 17/27] ima: Add functions for creating and " Stefan Berger
2022-03-02 13:46 ` [PATCH v11 18/27] integrity/ima: Define ns_status for storing namespaced iint data Stefan Berger
2022-03-02 13:46 ` [PATCH v11 19/27] integrity: Add optional callback function to integrity_inode_free() Stefan Berger
2022-03-02 13:46 ` [PATCH v11 20/27] ima: Namespace audit status flags Stefan Berger
2022-03-02 13:46 ` [PATCH v11 21/27] ima: Remove unused iints from the integrity_iint_cache Stefan Berger
2022-03-02 13:46 ` [PATCH v11 22/27] ima: Setup securityfs for IMA namespace Stefan Berger
2022-03-02 13:46 ` [PATCH v11 23/27] ima: Introduce securityfs file to activate an " Stefan Berger
2022-03-02 19:16 ` kernel test robot
2022-03-02 13:46 ` [PATCH v11 24/27] ima: Show owning user namespace's uid and gid when displaying policy Stefan Berger
2022-03-02 13:47 ` [PATCH v11 25/27] ima: Limit number of policy rules in non-init_ima_ns Stefan Berger
2022-03-02 13:47 ` [PATCH v11 26/27] ima: Restrict informational audit messages to init_ima_ns Stefan Berger
2022-03-02 23:11 ` kernel test robot
2022-03-02 13:47 ` [PATCH v11 27/27] ima: Enable IMA namespaces Stefan Berger
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