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Commit dd8dbf2e authored by Eric Paris's avatar Eric Paris Committed by James Morris
Browse files

security: report the module name to security_module_request 



For SELinux to do better filtering in userspace we send the name of the
module along with the AVC denial when a program is denied module_request.

Example output:

type=SYSCALL msg=audit(11/03/2009 10:59:43.510:9) : arch=x86_64 syscall=write success=yes exit=2 a0=3 a1=7fc28c0d56c0 a2=2 a3=7fffca0d7440 items=0 ppid=1727 pid=1729 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=unset comm=rpc.nfsd exe=/usr/sbin/rpc.nfsd subj=system_u:system_r:nfsd_t:s0 key=(null)
type=AVC msg=audit(11/03/2009 10:59:43.510:9) : avc:  denied  { module_request } for  pid=1729 comm=rpc.nfsd kmod="net-pf-10" scontext=system_u:system_r:nfsd_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=system

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 6e65f92f

include/linux/lsm_audit.h

+10 −8
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ struct common_audit_data { 
#define LSM_AUDIT_DATA_TASK	5

#define LSM_AUDIT_DATA_KEY	6

#define LSM_AUDIT_NO_AUDIT	7

#define LSM_AUDIT_DATA_KMOD	8

	struct task_struct *tsk;

	union 	{

		struct {
@@ -66,6 +67,7 @@ struct common_audit_data { 
			char *key_desc;

		} key_struct;

#endif

		char *kmod_name;

	} u;

	/* this union contains LSM specific data */

	union {

include/linux/security.h

+4 −3
Original line number Diff line number Diff line
@@ -706,6 +706,7 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) 
 * @kernel_module_request:

 *	Ability to trigger the kernel to automatically upcall to userspace for

 *	userspace to load a kernel module with the given name.

 *	@kmod_name name of the module requested by the kernel

 *	Return 0 if successful.

 * @task_setuid:

 *	Check permission before setting one or more of the user identity
@@ -1577,7 +1578,7 @@ struct security_operations { 
	void (*cred_transfer)(struct cred *new, const struct cred *old);

	int (*kernel_act_as)(struct cred *new, u32 secid);

	int (*kernel_create_files_as)(struct cred *new, struct inode *inode);

	int (*kernel_module_request)(void);

	int (*kernel_module_request)(char *kmod_name);

	int (*task_setuid) (uid_t id0, uid_t id1, uid_t id2, int flags);

	int (*task_fix_setuid) (struct cred *new, const struct cred *old,

				int flags);
@@ -1842,7 +1843,7 @@ void security_commit_creds(struct cred *new, const struct cred *old); 
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(void);

int security_kernel_module_request(char *kmod_name);

int security_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags);

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

			     int flags);
@@ -2407,7 +2408,7 @@ static inline int security_kernel_create_files_as(struct cred *cred, 
	return 0;

}



static inline int security_kernel_module_request(void)

static inline int security_kernel_module_request(char *kmod_name)

{

	return 0;

}

kernel/kmod.c

+4 −4
Original line number Diff line number Diff line
@@ -80,16 +80,16 @@ int __request_module(bool wait, const char *fmt, ...) 
#define MAX_KMOD_CONCURRENT 50	/* Completely arbitrary value - KAO */

	static int kmod_loop_msg;



	ret = security_kernel_module_request();

	if (ret)

		return ret;



	va_start(args, fmt);

	ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args);

	va_end(args);

	if (ret >= MODULE_NAME_LEN)

		return -ENAMETOOLONG;



	ret = security_kernel_module_request(module_name);

	if (ret)

		return ret;



	/* If modprobe needs a service that is in a module, we get a recursive

	 * loop.  Limit the number of running kmod threads to max_threads/2 or

	 * MAX_KMOD_CONCURRENT, whichever is the smaller.  A cleaner method

security/capability.c

+1 −1
Original line number Diff line number Diff line
@@ -421,7 +421,7 @@ static int cap_kernel_create_files_as(struct cred *new, struct inode *inode) 
	return 0;

}



static int cap_kernel_module_request(void)

static int cap_kernel_module_request(char *kmod_name)

{

	return 0;

}

security/lsm_audit.c

+4 −0
Original line number Diff line number Diff line
@@ -354,6 +354,10 @@ static void dump_common_audit_data(struct audit_buffer *ab, 
		}

		break;

#endif

	case LSM_AUDIT_DATA_KMOD:

		audit_log_format(ab, " kmod=");

		audit_log_untrustedstring(ab, a->u.kmod_name);

		break;

	} /* switch (a->type) */

}