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 <keesc...@chromium.org>
---
include/linux/security.h | 11 +++++++++++
kernel/module.c | 7 +++++++
security/capability.c | 6 ++++++
security/security.c | 5 +++++
4 files changed, 29 insertions(+), 0 deletions(-)
diff --git a/include/linux/security.h b/include/linux/security.h
index 3dea6a9..634d09a 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -693,6 +693,10 @@ 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 new kernel module from a file.
+ * @file contains the file structure being loaded as a kernel module.
+ * 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 +1511,7 @@ 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 +1769,7 @@ 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 +2283,11 @@ 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 0be8c11..1fcc63f 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>
@@ -2447,6 +2448,12 @@ static Elf_Ehdr *copy_module_from_fd(unsigned int fd,
unsigned long *len)
}
size = stat.size;
+ err = security_kernel_module_from_file(file);
+ if (err) {
+ hdr = ERR_PTR(err);
+ goto out;
+ }
+
hdr = vmalloc(size);
if (!hdr) {
hdr = ERR_PTR(-ENOMEM);
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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