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Subject[PATCH v8 08/19] ima: Use mac_admin_ns_capable() to check corresponding capability
Date
From: Stefan Berger <stefanb@linux.ibm.com>

Use mac_admin_ns_capable() to check corresponding capability to allow
read/write IMA policy without CAP_SYS_ADMIN but with CAP_MAC_ADMIN.

Signed-off-by: Denis Semakin <denis.semakin@huawei.com>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
include/linux/capability.h | 6 ++++++
security/integrity/ima/ima.h | 6 ++++++
security/integrity/ima/ima_fs.c | 3 ++-
3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/linux/capability.h b/include/linux/capability.h
index 65efb74c3585..991579178f32 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(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 224b09617c52..0c86a955cedf 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -483,6 +483,12 @@ 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;
+}
+
static inline struct ima_namespace *get_current_ns(void)
{
return &init_ima_ns;
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 5b6404991b37..71302bb5427f 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -377,6 +377,7 @@ static const struct seq_operations ima_policy_seqops = {
*/
static int ima_open_policy(struct inode *inode, struct file *filp)
{
+ struct user_namespace *user_ns = ima_user_ns_from_file(filp);
struct ima_namespace *ns = &init_ima_ns;

if (!(filp->f_flags & O_WRONLY)) {
@@ -385,7 +386,7 @@ 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
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