3 files changed, 80 insertions, 0 deletions

diff --git a/include/linux/ima.h b/include/linux/ima.h
index e2bfbb1e9af6..2c7223d7e73b 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -44,10 +44,27 @@ static inline int ima_file_mmap(struct file *file, unsigned long prot)
 
 #ifdef CONFIG_IMA_APPRAISE
 extern void ima_inode_post_setattr(struct dentry *dentry);
+extern int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
+                       const void *xattr_value, size_t xattr_value_len);
+extern int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name);
 #else
 static inline void ima_inode_post_setattr(struct dentry *dentry)
 {
         return;
 }
+
+static inline int ima_inode_setxattr(struct dentry *dentry,
+                                     const char *xattr_name,
+                                     const void *xattr_value,
+                                     size_t xattr_value_len)
+{
+        return 0;
+}
+
+static inline int ima_inode_removexattr(struct dentry *dentry,
+                                        const char *xattr_name)
+{
+        return 0;
+}
 #endif /* CONFIG_IMA_APPRAISE_H */
 #endif /* _LINUX_IMA_H */
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 681cb6e72257..becc7e09116d 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -169,3 +169,60 @@ void ima_inode_post_setattr(struct dentry *dentry)
                 rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA);
         return;
 }
+
+/*
+ * ima_protect_xattr - protect 'security.ima'
+ *
+ * Ensure that not just anyone can modify or remove 'security.ima'.
+ */
+static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name,
+                             const void *xattr_value, size_t xattr_value_len)
+{
+        if (strcmp(xattr_name, XATTR_NAME_IMA) == 0) {
+                if (!capable(CAP_SYS_ADMIN))
+                        return -EPERM;
+                return 1;
+        }
+        return 0;
+}
+
+static void ima_reset_appraise_flags(struct inode *inode)
+{
+        struct integrity_iint_cache *iint;
+
+        if (!ima_initialized || !ima_appraise || !S_ISREG(inode->i_mode))
+                return;
+
+        iint = integrity_iint_find(inode);
+        if (!iint)
+                return;
+
+        iint->flags &= ~(IMA_COLLECTED | IMA_APPRAISED | IMA_MEASURED);
+        return;
+}
+
+int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
+                       const void *xattr_value, size_t xattr_value_len)
+{
+        int result;
+
+        result = ima_protect_xattr(dentry, xattr_name, xattr_value,
+                                   xattr_value_len);
+        if (result == 1) {
+                ima_reset_appraise_flags(dentry->d_inode);
+                result = 0;
+        }
+        return result;
+}
+
+int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name)
+{
+        int result;
+
+        result = ima_protect_xattr(dentry, xattr_name, NULL, 0);
+        if (result == 1) {
+                ima_reset_appraise_flags(dentry->d_inode);
+                result = 0;
+        }
+        return result;
+}
diff --git a/security/security.c b/security/security.c
index 68c1b9b45d93..d23b43522a5a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -573,6 +573,9 @@ int security_inode_setxattr(struct dentry *dentry, const char *name,
         ret = security_ops->inode_setxattr(dentry, name, value, size, flags);
         if (ret)
                 return ret;
+        ret = ima_inode_setxattr(dentry, name, value, size);
+        if (ret)
+                return ret;
         return evm_inode_setxattr(dentry, name, value, size);
 }
 
@@ -608,6 +611,9 @@ int security_inode_removexattr(struct dentry *dentry, const char *name)
         ret = security_ops->inode_removexattr(dentry, name);
         if (ret)
                 return ret;
+        ret = ima_inode_removexattr(dentry, name);
+        if (ret)
+                return ret;
         return evm_inode_removexattr(dentry, name);
 }