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From: Jeff Mahoney <jeffm@suse.com>
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Subject: [PATCH] security: add ->path_permission
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This patch adds a security_ops->path_permission hook that is identical to
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security_ops->inode_permission except that it is passed a struct path
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instead of a struct inode.
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LSMs which don't implement it will have their ->inode_permission call
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Signed-off-by: Jeff Mahoney <jeffm@suse.com>
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include/linux/security.h | 21 +++++++++++++++++++++
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security/capability.c | 6 ++++++
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security/security.c | 9 +++++++++
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3 files changed, 36 insertions(+)
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--- a/include/linux/security.h
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+++ b/include/linux/security.h
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@@ -592,6 +592,20 @@ static inline void security_free_mnt_opt
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* file_permission, and recheck access if anything has changed
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* since inode_permission.
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+ * Security hook for path
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+ * Check permission before accessing a path. This hook is called by the
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+ * existing Linux permission function, so a security module can use it to
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+ * provide additional checking for existing Linux permission checks.
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+ * Notice that this hook is called when a file is opened (as well as many
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+ * other operations), whereas the file_security_ops permission hook is
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+ * called when the actual read/write operations are performed. This
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+ * hook is optional and if absent, inode_permission will be substituted.
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+ * @path contains the path structure to check.
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+ * @mask contains the permission mask.
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+ * Return 0 if permission is granted.
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* Security hooks for task operations.
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@@ -1434,6 +1448,7 @@ struct security_operations {
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struct fown_struct *fown, int sig);
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int (*file_receive) (struct file *file);
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int (*dentry_open) (struct file *file);
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+ int (*path_permission) (struct path *path, int mask);
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int (*task_create) (unsigned long clone_flags);
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int (*task_alloc_security) (struct task_struct *p);
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@@ -1708,6 +1723,7 @@ int security_file_send_sigiotask(struct
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struct fown_struct *fown, int sig);
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int security_file_receive(struct file *file);
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int security_dentry_open(struct file *file);
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+int security_path_permission(struct path *path, int mask);
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int security_task_create(unsigned long clone_flags);
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int security_task_alloc(struct task_struct *p);
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void security_task_free(struct task_struct *p);
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@@ -2240,6 +2256,11 @@ static inline int security_dentry_open(s
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+static inline int security_path_permission(struct path *path, int mask)
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static inline int security_task_create(unsigned long clone_flags)
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--- a/security/capability.c
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+++ b/security/capability.c
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@@ -343,6 +343,11 @@ static int cap_dentry_open(struct file *
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+static int cap_path_permission(struct path *path, int mask)
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+ return security_inode_permission(path->dentry->d_inode, mask);
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static int cap_task_create(unsigned long clone_flags)
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@@ -897,6 +902,7 @@ void security_fixup_ops(struct security_
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set_to_cap_if_null(ops, file_send_sigiotask);
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set_to_cap_if_null(ops, file_receive);
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set_to_cap_if_null(ops, dentry_open);
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+ set_to_cap_if_null(ops, path_permission);
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set_to_cap_if_null(ops, task_create);
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set_to_cap_if_null(ops, task_alloc_security);
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set_to_cap_if_null(ops, task_free_security);
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--- a/security/security.c
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+++ b/security/security.c
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@@ -615,6 +615,15 @@ int security_dentry_open(struct file *fi
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return security_ops->dentry_open(file);
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+int security_path_permission(struct path *path, int mask)
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+ struct inode *inode = path->dentry->d_inode;
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+ if (unlikely(IS_PRIVATE(inode)))
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+ return security_ops->path_permission(path, mask);
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int security_task_create(unsigned long clone_flags)
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return security_ops->task_create(clone_flags);