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Message-Id: <1347043094-11120-2-git-send-email-keescook@chromium.org>
Date: Fri, 7 Sep 2012 11:38:14 -0700
From: Kees Cook <keescook@...omium.org>
To: linux-kernel@...r.kernel.org
Cc: Rusty Russell <rusty@...tcorp.com.au>,
Mimi Zohar <zohar@...ux.vnet.ibm.com>,
Serge Hallyn <serge.hallyn@...onical.com>,
James Morris <james.l.morris@...cle.com>,
Al Viro <viro@...iv.linux.org.uk>,
Eric Paris <eparis@...hat.com>,
Kees Cook <keescook@...omium.org>,
Jiri Kosina <jkosina@...e.cz>,
linux-security-module@...r.kernel.org
Subject: [PATCH 2/2] security: introduce kernel_module_from_file hook
Now that kernel module origins can be reasoned about, provide a hook to
the LSMs to make policy decisions about the module file.
Signed-off-by: Kees Cook <keescook@...omium.org>
Acked-by: Serge E. Hallyn <serge.hallyn@...onical.com>
---
include/linux/security.h | 13 +++++++++++++
kernel/module.c | 9 +++++++++
security/capability.c | 6 ++++++
security/security.c | 5 +++++
4 files changed, 33 insertions(+), 0 deletions(-)
diff --git a/include/linux/security.h b/include/linux/security.h
index 3dea6a9..368e539 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -693,6 +693,12 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
* userspace to load a kernel module with the given name.
* @kmod_name name of the module requested by the kernel
* Return 0 if successful.
+ * @kernel_module_from_file:
+ * Load a kernel module from userspace.
+ * @file contains the file structure pointing to the file containing
+ * the kernel module to load. If the module is being loaded from a blob,
+ * this argument will be NULL.
+ * Return 0 if permission is granted.
* @task_fix_setuid:
* Update the module's state after setting one or more of the user
* identity attributes of the current process. The @flags parameter
@@ -1507,6 +1513,7 @@ struct security_operations {
int (*kernel_act_as)(struct cred *new, u32 secid);
int (*kernel_create_files_as)(struct cred *new, struct inode *inode);
int (*kernel_module_request)(char *kmod_name);
+ int (*kernel_module_from_file)(struct file *file);
int (*task_fix_setuid) (struct cred *new, const struct cred *old,
int flags);
int (*task_setpgid) (struct task_struct *p, pid_t pgid);
@@ -1764,6 +1771,7 @@ void security_transfer_creds(struct cred *new, const struct cred *old);
int security_kernel_act_as(struct cred *new, u32 secid);
int security_kernel_create_files_as(struct cred *new, struct inode *inode);
int security_kernel_module_request(char *kmod_name);
+int security_kernel_module_from_file(struct file *file);
int security_task_fix_setuid(struct cred *new, const struct cred *old,
int flags);
int security_task_setpgid(struct task_struct *p, pid_t pgid);
@@ -2277,6 +2285,11 @@ static inline int security_kernel_module_request(char *kmod_name)
return 0;
}
+static inline int security_kernel_module_from_file(struct file *file)
+{
+ return 0;
+}
+
static inline int security_task_fix_setuid(struct cred *new,
const struct cred *old,
int flags)
diff --git a/kernel/module.c b/kernel/module.c
index c1e446e..0ad03c4 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -29,6 +29,7 @@
#include <linux/vmalloc.h>
#include <linux/elf.h>
#include <linux/proc_fs.h>
+#include <linux/security.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/fcntl.h>
@@ -2430,6 +2431,10 @@ int copy_module_from_user(const void __user *umod, unsigned long len,
if (info->len < sizeof(*(info->hdr)))
return -ENOEXEC;
+ err = security_kernel_module_from_file(NULL);
+ if (err)
+ return err;
+
/* Suck in entire file: we'll want most of it. */
info->hdr = vmalloc(info->len);
if (!info->hdr)
@@ -2468,6 +2473,10 @@ int copy_module_from_fd(int fd, struct load_info *info)
if (err)
goto out;
+ err = security_kernel_module_from_file(file);
+ if (err)
+ goto out;
+
size = stat.size;
info->hdr = vmalloc(size);
if (!info->hdr) {
diff --git a/security/capability.c b/security/capability.c
index 61095df..8acb304 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -395,6 +395,11 @@ static int cap_kernel_module_request(char *kmod_name)
return 0;
}
+static int cap_kernel_module_from_file(struct file *file)
+{
+ return 0;
+}
+
static int cap_task_setpgid(struct task_struct *p, pid_t pgid)
{
return 0;
@@ -967,6 +972,7 @@ void __init security_fixup_ops(struct security_operations *ops)
set_to_cap_if_null(ops, kernel_act_as);
set_to_cap_if_null(ops, kernel_create_files_as);
set_to_cap_if_null(ops, kernel_module_request);
+ set_to_cap_if_null(ops, kernel_module_from_file);
set_to_cap_if_null(ops, task_fix_setuid);
set_to_cap_if_null(ops, task_setpgid);
set_to_cap_if_null(ops, task_getpgid);
diff --git a/security/security.c b/security/security.c
index 860aeb3..f7f8695 100644
--- a/security/security.c
+++ b/security/security.c
@@ -799,6 +799,11 @@ int security_kernel_module_request(char *kmod_name)
return security_ops->kernel_module_request(kmod_name);
}
+int security_kernel_module_from_file(struct file *file)
+{
+ return security_ops->kernel_module_from_file(file);
+}
+
int security_task_fix_setuid(struct cred *new, const struct cred *old,
int flags)
{
--
1.7.0.4
--
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