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Commit 377179cd authored by Mimi Zohar's avatar Mimi Zohar Committed by James Morris
Browse files

security: define new LSM hook named security_kernel_load_data 



Differentiate between the kernel reading a file specified by userspace
from the kernel loading a buffer containing data provided by userspace.
This patch defines a new LSM hook named security_kernel_load_data().

Signed-off-by: default avatarMimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: default avatarSerge Hallyn <serge@hallyn.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarJames Morris <james.morris@microsoft.com>
parent 57b54d74

include/linux/lsm_hooks.h

+6 −0
Original line number Diff line number Diff line
@@ -576,6 +576,10 @@ 
 *	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_load_data:

 *	Load data provided by userspace.

 *	@id kernel load data identifier

 *	Return 0 if permission is granted.

 * @kernel_read_file:

 *	Read a file specified by userspace.

 *	@file contains the file structure pointing to the file being read
@@ -1582,6 +1586,7 @@ union security_list_options { 
	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_load_data)(enum kernel_load_data_id id);

	int (*kernel_read_file)(struct file *file, enum kernel_read_file_id id);

	int (*kernel_post_read_file)(struct file *file, char *buf, loff_t size,

				     enum kernel_read_file_id id);
@@ -1872,6 +1877,7 @@ struct security_hook_heads { 
	struct hlist_head cred_getsecid;

	struct hlist_head kernel_act_as;

	struct hlist_head kernel_create_files_as;

	struct hlist_head kernel_load_data;

	struct hlist_head kernel_read_file;

	struct hlist_head kernel_post_read_file;

	struct hlist_head kernel_module_request;

include/linux/security.h

+27 −0
Original line number Diff line number Diff line
@@ -159,6 +159,27 @@ extern int mmap_min_addr_handler(struct ctl_table *table, int write, 
typedef int (*initxattrs) (struct inode *inode,

			   const struct xattr *xattr_array, void *fs_data);





/* Keep the kernel_load_data_id enum in sync with kernel_read_file_id */

#define __data_id_enumify(ENUM, dummy) LOADING_ ## ENUM,

#define __data_id_stringify(dummy, str) #str,



enum kernel_load_data_id {

	__kernel_read_file_id(__data_id_enumify)

};



static const char * const kernel_load_data_str[] = {

	__kernel_read_file_id(__data_id_stringify)

};



static inline const char *kernel_load_data_id_str(enum kernel_load_data_id id)

{

	if ((unsigned)id >= LOADING_MAX_ID)

		return kernel_load_data_str[LOADING_UNKNOWN];



	return kernel_load_data_str[id];

}



#ifdef CONFIG_SECURITY



struct security_mnt_opts {
@@ -320,6 +341,7 @@ void security_cred_getsecid(const struct cred *c, u32 *secid); 
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_load_data(enum kernel_load_data_id id);

int security_kernel_read_file(struct file *file, enum kernel_read_file_id id);

int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,

				   enum kernel_read_file_id id);
@@ -909,6 +931,11 @@ static inline int security_kernel_module_request(char *kmod_name) 
	return 0;

}



static inline int security_kernel_load_data(enum kernel_load_data_id id)

{

	return 0;

}



static inline int security_kernel_read_file(struct file *file,

					    enum kernel_read_file_id id)

{

security/security.c

+5 −0
Original line number Diff line number Diff line
@@ -1056,6 +1056,11 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size, 
}

EXPORT_SYMBOL_GPL(security_kernel_post_read_file);



int security_kernel_load_data(enum kernel_load_data_id id)

{

	return call_int_hook(kernel_load_data, 0, id);

}



int security_task_fix_setuid(struct cred *new, const struct cred *old,

			     int flags)

{