@@ -56,6 +56,7 @@ static struct file_system_type anon_inode_fs_type = {
};
static struct inode *anon_inode_make_secure_inode(
+ enum lsm_anon_inode_type type,
const char *name,
const struct inode *context_inode)
{
@@ -67,7 +68,8 @@ static struct inode *anon_inode_make_secure_inode(
if (IS_ERR(inode))
return inode;
inode->i_flags &= ~S_PRIVATE;
- error = security_inode_init_security_anon(inode, &qname, context_inode);
+ error = security_inode_init_security_anon(inode, type, &qname,
+ context_inode);
if (error) {
iput(inode);
return ERR_PTR(error);
@@ -75,11 +77,11 @@ static struct inode *anon_inode_make_secure_inode(
return inode;
}
-static struct file *__anon_inode_getfile(const char *name,
+static struct file *__anon_inode_getfile(enum lsm_anon_inode_type type,
+ const char *name,
const struct file_operations *fops,
void *priv, int flags,
- const struct inode *context_inode,
- bool secure)
+ const struct inode *context_inode)
{
struct inode *inode;
struct file *file;
@@ -87,8 +89,8 @@ static struct file *__anon_inode_getfile(const char *name,
if (fops->owner && !try_module_get(fops->owner))
return ERR_PTR(-ENOENT);
- if (secure) {
- inode = anon_inode_make_secure_inode(name, context_inode);
+ if (type != LSM_ANON_INODE_NONE) {
+ inode = anon_inode_make_secure_inode(type, name, context_inode);
if (IS_ERR(inode)) {
file = ERR_CAST(inode);
goto err;
@@ -144,15 +146,16 @@ struct file *anon_inode_getfile(const char *name,
const struct file_operations *fops,
void *priv, int flags)
{
- return __anon_inode_getfile(name, fops, priv, flags, NULL, false);
+ return __anon_inode_getfile(LSM_ANON_INODE_NONE, name, fops, priv,
+ flags, NULL);
}
EXPORT_SYMBOL_GPL(anon_inode_getfile);
-static int __anon_inode_getfd(const char *name,
+static int __anon_inode_getfd(enum lsm_anon_inode_type type,
+ const char *name,
const struct file_operations *fops,
void *priv, int flags,
- const struct inode *context_inode,
- bool secure)
+ const struct inode *context_inode)
{
int error, fd;
struct file *file;
@@ -162,8 +165,8 @@ static int __anon_inode_getfd(const char *name,
return error;
fd = error;
- file = __anon_inode_getfile(name, fops, priv, flags, context_inode,
- secure);
+ file = __anon_inode_getfile(type, name, fops, priv, flags,
+ context_inode);
if (IS_ERR(file)) {
error = PTR_ERR(file);
goto err_put_unused_fd;
@@ -197,7 +200,8 @@ err_put_unused_fd:
int anon_inode_getfd(const char *name, const struct file_operations *fops,
void *priv, int flags)
{
- return __anon_inode_getfd(name, fops, priv, flags, NULL, false);
+ return __anon_inode_getfd(LSM_ANON_INODE_NONE, name, fops, priv,
+ flags, NULL);
}
EXPORT_SYMBOL_GPL(anon_inode_getfd);
@@ -207,7 +211,9 @@ EXPORT_SYMBOL_GPL(anon_inode_getfd);
* the inode_init_security_anon() LSM hook. This allows the inode to have its
* own security context and for a LSM to reject creation of the inode.
*
- * @name: [in] name of the "class" of the new file
+ * @type: [in] type of the file recognizable by LSMs
+ * @name: [in] name of the "class" of the new file (may be more specific
+ * than @type)
* @fops: [in] file operations for the new file
* @priv: [in] private data for the new file (will be file's private_data)
* @flags: [in] flags
@@ -217,11 +223,15 @@ EXPORT_SYMBOL_GPL(anon_inode_getfd);
* The LSM may use @context_inode in inode_init_security_anon(), but a
* reference to it is not held.
*/
-int anon_inode_getfd_secure(const char *name, const struct file_operations *fops,
+int anon_inode_getfd_secure(enum lsm_anon_inode_type type, const char *name,
+ const struct file_operations *fops,
void *priv, int flags,
const struct inode *context_inode)
{
- return __anon_inode_getfd(name, fops, priv, flags, context_inode, true);
+ /* The caller must pass a valid type! */
+ if (WARN_ON(type <= LSM_ANON_INODE_NONE || type > LSM_ANON_INODE_MAX))
+ return -EINVAL;
+ return __anon_inode_getfd(type, name, fops, priv, flags, context_inode);
}
EXPORT_SYMBOL_GPL(anon_inode_getfd_secure);
@@ -985,7 +985,8 @@ static int resolve_userfault_fork(struct userfaultfd_ctx *new,
{
int fd;
- fd = anon_inode_getfd_secure("[userfaultfd]", &userfaultfd_fops, new,
+ fd = anon_inode_getfd_secure(LSM_ANON_INODE_USERFAULTFD,
+ "[userfaultfd]", &userfaultfd_fops, new,
O_RDWR | (new->flags & UFFD_SHARED_FCNTL_FLAGS), inode);
if (fd < 0)
return fd;
@@ -2000,7 +2001,8 @@ SYSCALL_DEFINE1(userfaultfd, int, flags)
/* prevent the mm struct to be freed */
mmgrab(ctx->mm);
- fd = anon_inode_getfd_secure("[userfaultfd]", &userfaultfd_fops, ctx,
+ fd = anon_inode_getfd_secure(LSM_ANON_INODE_USERFAULTFD,
+ "[userfaultfd]", &userfaultfd_fops, ctx,
O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS), NULL);
if (fd < 0) {
mmdrop(ctx->mm);
@@ -9,6 +9,8 @@
#ifndef _LINUX_ANON_INODES_H
#define _LINUX_ANON_INODES_H
+#include <linux/security.h>
+
struct file_operations;
struct inode;
@@ -17,7 +19,7 @@ struct file *anon_inode_getfile(const char *name,
void *priv, int flags);
int anon_inode_getfd(const char *name, const struct file_operations *fops,
void *priv, int flags);
-int anon_inode_getfd_secure(const char *name,
+int anon_inode_getfd_secure(enum lsm_anon_inode_type type, const char *name,
const struct file_operations *fops,
void *priv, int flags,
const struct inode *context_inode);
@@ -115,7 +115,8 @@ LSM_HOOK(int, 0, inode_init_security, struct inode *inode,
struct inode *dir, const struct qstr *qstr, const char **name,
void **value, size_t *len)
LSM_HOOK(int, 0, inode_init_security_anon, struct inode *inode,
- const struct qstr *name, const struct inode *context_inode)
+ enum lsm_anon_inode_type type, const struct qstr *name,
+ const struct inode *context_inode)
LSM_HOOK(int, 0, inode_create, struct inode *dir, struct dentry *dentry,
umode_t mode)
LSM_HOOK(int, 0, inode_link, struct dentry *old_dentry, struct inode *dir,
@@ -79,6 +79,23 @@ enum lsm_event {
LSM_POLICY_CHANGE,
};
+/*
+ * Types of anonymous inodes that may be interesting to LSMs.
+ * Passed to anon_inode_getfd_secure() and
+ * security_inode_init_security_anon().
+ */
+enum lsm_anon_inode_type {
+ /* anon inodes invisible to the LSMs */
+ LSM_ANON_INODE_NONE = 0,
+ /* userfaultfd anon inodes */
+ LSM_ANON_INODE_USERFAULTFD,
+ /* (add new types above this line) */
+
+ __LSM_ANON_INODE_MAX,
+ /* max value used for asserts */
+ LSM_ANON_INODE_MAX = __LSM_ANON_INODE_MAX - 1,
+};
+
/*
* These are reasons that can be passed to the security_locked_down()
* LSM hook. Lockdown reasons that protect kernel integrity (ie, the
@@ -329,6 +346,7 @@ int security_inode_init_security(struct inode *inode, struct inode *dir,
const struct qstr *qstr,
initxattrs initxattrs, void *fs_data);
int security_inode_init_security_anon(struct inode *inode,
+ enum lsm_anon_inode_type type,
const struct qstr *name,
const struct inode *context_inode);
int security_old_inode_init_security(struct inode *inode, struct inode *dir,
@@ -759,6 +777,7 @@ static inline int security_inode_init_security(struct inode *inode,
}
static inline int security_inode_init_security_anon(struct inode *inode,
+ enum lsm_anon_inode_type type,
const struct qstr *name,
const struct inode *context_inode)
{
@@ -1067,10 +1067,11 @@ out:
EXPORT_SYMBOL(security_inode_init_security);
int security_inode_init_security_anon(struct inode *inode,
+ enum lsm_anon_inode_type type,
const struct qstr *name,
const struct inode *context_inode)
{
- return call_int_hook(inode_init_security_anon, 0, inode, name,
+ return call_int_hook(inode_init_security_anon, 0, inode, type, name,
context_inode);
}
@@ -3048,6 +3048,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
}
static int selinux_inode_init_security_anon(struct inode *inode,
+ enum lsm_anon_inode_type type,
const struct qstr *name,
const struct inode *context_inode)
{
Add an enum to <linux/security.h> that allows LSMs to reliably distinguish types of anon inodes created via anon_inode_getfd_secure() and require callers of this function to pass the type as an argument. For the single current user of this function (userfaultfd), add the corresponding type and pass it in its anon_inode_getfd_secure() call. While the "name" argument can be used to distinguish different types as well, some users of anon_inode_getfd() put some additional information here (e.g. KVM anon inodes), so using an explicit numeric identifier is preferred to parsing this information from strings. The new type information will be used by SELinux in a subsequent patch. Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> --- fs/anon_inodes.c | 42 ++++++++++++++++++++++------------- fs/userfaultfd.c | 6 +++-- include/linux/anon_inodes.h | 4 +++- include/linux/lsm_hook_defs.h | 3 ++- include/linux/security.h | 19 ++++++++++++++++ security/security.c | 3 ++- security/selinux/hooks.c | 1 + 7 files changed, 57 insertions(+), 21 deletions(-)