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* [RFC] LSM fix for stupid "empty" functions
@ 2002-12-01  8:30 Greg KH
  2002-12-01  8:17 ` Crispin Cowan
                   ` (2 more replies)
  0 siblings, 3 replies; 23+ messages in thread
From: Greg KH @ 2002-12-01  8:30 UTC (permalink / raw)
  To: linux-security-module; +Cc: linux-kernel

Hi all,

I'm _really_ tired of all of the "empty" functions that all security
modules need to provide.  So here's a brute force patch that lets any
security module only set the functions that it wants to override.  If
the function is NULL, then the "dummy" function will be used instead.

What do people think of this?  I also cleaned up the comment in the
verify function of security/security.c and made it not inline.

Comments welcome (if there are none, I'll send it on to Linus.)  The
patch below is against 2.5.50.  As you can see by the diffstat, it does
make security modules a lot smaller :)

We could also remove all of the initializers for dummy_security_ops with
this patch, reducing the code size some more, if people really want
to...

thanks,

greg k-h


 security/capability.c |  530 --------------------------------------------------
 security/dummy.c      |  164 ++++++++++++---
 security/security.c   |   14 -
 3 files changed, 142 insertions(+), 566 deletions(-)


===== security/capability.c 1.10 vs edited =====
--- 1.10/security/capability.c	Sun Nov 24 15:27:58 2002
+++ edited/security/capability.c	Sat Nov 30 23:08:59 2002
@@ -279,550 +279,20 @@
 
 #ifdef CONFIG_SECURITY
 
-static int cap_quotactl (int cmds, int type, int id, struct super_block *sb)
-{
-	return 0;
-}
-
-static int cap_quota_on (struct file *f)
-{
-	return 0;
-}
-
-static int cap_acct (struct file *file)
-{
-	return 0;
-}
-
-static int cap_bprm_alloc_security (struct linux_binprm *bprm)
-{
-	return 0;
-}
-
-static int cap_bprm_check_security (struct linux_binprm *bprm)
-{
-	return 0;
-}
-
-static void cap_bprm_free_security (struct linux_binprm *bprm)
-{
-	return;
-}
-
-static int cap_sb_alloc_security (struct super_block *sb)
-{
-	return 0;
-}
-
-static void cap_sb_free_security (struct super_block *sb)
-{
-	return;
-}
-
-static int cap_sb_statfs (struct super_block *sb)
-{
-	return 0;
-}
-
-static int cap_mount (char *dev_name, struct nameidata *nd, char *type,
-		      unsigned long flags, void *data)
-{
-	return 0;
-}
-
-static int cap_check_sb (struct vfsmount *mnt, struct nameidata *nd)
-{
-	return 0;
-}
-
-static int cap_umount (struct vfsmount *mnt, int flags)
-{
-	return 0;
-}
-
-static void cap_umount_close (struct vfsmount *mnt)
-{
-	return;
-}
-
-static void cap_umount_busy (struct vfsmount *mnt)
-{
-	return;
-}
-
-static void cap_post_remount (struct vfsmount *mnt, unsigned long flags,
-			      void *data)
-{
-	return;
-}
-
-static void cap_post_mountroot (void)
-{
-	return;
-}
-
-static void cap_post_addmount (struct vfsmount *mnt, struct nameidata *nd)
-{
-	return;
-}
-
-static int cap_pivotroot (struct nameidata *old_nd, struct nameidata *new_nd)
-{
-	return 0;
-}
-
-static void cap_post_pivotroot (struct nameidata *old_nd, struct nameidata *new_nd)
-{
-	return;
-}
-
-static int cap_inode_alloc_security (struct inode *inode)
-{
-	return 0;
-}
-
-static void cap_inode_free_security (struct inode *inode)
-{
-	return;
-}
-
-static int cap_inode_create (struct inode *inode, struct dentry *dentry,
-			     int mask)
-{
-	return 0;
-}
-
-static void cap_inode_post_create (struct inode *inode, struct dentry *dentry,
-				   int mask)
-{
-	return;
-}
-
-static int cap_inode_link (struct dentry *old_dentry, struct inode *inode,
-			   struct dentry *new_dentry)
-{
-	return 0;
-}
-
-static void cap_inode_post_link (struct dentry *old_dentry, struct inode *inode,
-				 struct dentry *new_dentry)
-{
-	return;
-}
-
-static int cap_inode_unlink (struct inode *inode, struct dentry *dentry)
-{
-	return 0;
-}
-
-static int cap_inode_symlink (struct inode *inode, struct dentry *dentry,
-			      const char *name)
-{
-	return 0;
-}
-
-static void cap_inode_post_symlink (struct inode *inode, struct dentry *dentry,
-				    const char *name)
-{
-	return;
-}
-
-static int cap_inode_mkdir (struct inode *inode, struct dentry *dentry,
-			    int mask)
-{
-	return 0;
-}
-
-static void cap_inode_post_mkdir (struct inode *inode, struct dentry *dentry,
-				  int mask)
-{
-	return;
-}
-
-static int cap_inode_rmdir (struct inode *inode, struct dentry *dentry)
-{
-	return 0;
-}
-
-static int cap_inode_mknod (struct inode *inode, struct dentry *dentry,
-			    int mode, dev_t dev)
-{
-	return 0;
-}
-
-static void cap_inode_post_mknod (struct inode *inode, struct dentry *dentry,
-				  int mode, dev_t dev)
-{
-	return;
-}
-
-static int cap_inode_rename (struct inode *old_inode, struct dentry *old_dentry,
-			     struct inode *new_inode, struct dentry *new_dentry)
-{
-	return 0;
-}
-
-static void cap_inode_post_rename (struct inode *old_inode,
-				   struct dentry *old_dentry,
-				   struct inode *new_inode,
-				   struct dentry *new_dentry)
-{
-	return;
-}
-
-static int cap_inode_readlink (struct dentry *dentry)
-{
-	return 0;
-}
-
-static int cap_inode_follow_link (struct dentry *dentry,
-				  struct nameidata *nameidata)
-{
-	return 0;
-}
-
-static int cap_inode_permission (struct inode *inode, int mask)
-{
-	return 0;
-}
-
-static int cap_inode_permission_lite (struct inode *inode, int mask)
-{
-	return 0;
-}
-
-static int cap_inode_setattr (struct dentry *dentry, struct iattr *iattr)
-{
-	return 0;
-}
-
-static int cap_inode_getattr (struct vfsmount *mnt, struct dentry *dentry)
-{
-	return 0;
-}
-
-static void cap_post_lookup (struct inode *ino, struct dentry *d)
-{
-	return;
-}
-
-static void cap_delete (struct inode *ino)
-{
-	return;
-}
-
-static int cap_inode_setxattr (struct dentry *dentry, char *name, void *value,
-				size_t size, int flags)
-{
-	return 0;
-}
-
-static int cap_inode_getxattr (struct dentry *dentry, char *name)
-{
-	return 0;
-}
-
-static int cap_inode_listxattr (struct dentry *dentry)
-{
-	return 0;
-}
-
-static int cap_inode_removexattr (struct dentry *dentry, char *name)
-{
-	return 0;
-}
-
-static int cap_file_permission (struct file *file, int mask)
-{
-	return 0;
-}
-
-static int cap_file_alloc_security (struct file *file)
-{
-	return 0;
-}
-
-static void cap_file_free_security (struct file *file)
-{
-	return;
-}
-
-static int cap_file_ioctl (struct file *file, unsigned int command,
-			   unsigned long arg)
-{
-	return 0;
-}
-
-static int cap_file_mmap (struct file *file, unsigned long prot,
-			  unsigned long flags)
-{
-	return 0;
-}
-
-static int cap_file_mprotect (struct vm_area_struct *vma, unsigned long prot)
-{
-	return 0;
-}
-
-static int cap_file_lock (struct file *file, unsigned int cmd)
-{
-	return 0;
-}
-
-static int cap_file_fcntl (struct file *file, unsigned int cmd,
-			   unsigned long arg)
-{
-	return 0;
-}
-
-static int cap_file_set_fowner (struct file *file)
-{
-	return 0;
-}
-
-static int cap_file_send_sigiotask (struct task_struct *tsk,
-				    struct fown_struct *fown, int fd,
-				    int reason)
-{
-	return 0;
-}
-
-static int cap_file_receive (struct file *file)
-{
-	return 0;
-}
-
-static int cap_task_create (unsigned long clone_flags)
-{
-	return 0;
-}
-
-static int cap_task_alloc_security (struct task_struct *p)
-{
-	return 0;
-}
-
-static void cap_task_free_security (struct task_struct *p)
-{
-	return;
-}
-
-static int cap_task_setuid (uid_t id0, uid_t id1, uid_t id2, int flags)
-{
-	return 0;
-}
-
-static int cap_task_setgid (gid_t id0, gid_t id1, gid_t id2, int flags)
-{
-	return 0;
-}
-
-static int cap_task_setpgid (struct task_struct *p, pid_t pgid)
-{
-	return 0;
-}
-
-static int cap_task_getpgid (struct task_struct *p)
-{
-	return 0;
-}
-
-static int cap_task_getsid (struct task_struct *p)
-{
-	return 0;
-}
-
-static int cap_task_setgroups (int gidsetsize, gid_t * grouplist)
-{
-	return 0;
-}
-
-static int cap_task_setnice (struct task_struct *p, int nice)
-{
-	return 0;
-}
-
-static int cap_task_setrlimit (unsigned int resource, struct rlimit *new_rlim)
-{
-	return 0;
-}
-
-static int cap_task_setscheduler (struct task_struct *p, int policy,
-				  struct sched_param *lp)
-{
-	return 0;
-}
-
-static int cap_task_getscheduler (struct task_struct *p)
-{
-	return 0;
-}
-
-static int cap_task_wait (struct task_struct *p)
-{
-	return 0;
-}
-
-static int cap_task_kill (struct task_struct *p, struct siginfo *info, int sig)
-{
-	return 0;
-}
-
-static int cap_task_prctl (int option, unsigned long arg2, unsigned long arg3,
-			   unsigned long arg4, unsigned long arg5)
-{
-	return 0;
-}
-
-static int cap_ipc_permission (struct kern_ipc_perm *ipcp, short flag)
-{
-	return 0;
-}
-
-static int cap_msg_queue_alloc_security (struct msg_queue *msq)
-{
-	return 0;
-}
-
-static void cap_msg_queue_free_security (struct msg_queue *msq)
-{
-	return;
-}
-
-static int cap_shm_alloc_security (struct shmid_kernel *shp)
-{
-	return 0;
-}
-
-static void cap_shm_free_security (struct shmid_kernel *shp)
-{
-	return;
-}
-
-static int cap_sem_alloc_security (struct sem_array *sma)
-{
-	return 0;
-}
-
-static void cap_sem_free_security (struct sem_array *sma)
-{
-	return;
-}
-
-static int cap_register (const char *name, struct security_operations *ops)
-{
-	return -EINVAL;
-}
-
-static int cap_unregister (const char *name, struct security_operations *ops)
-{
-	return -EINVAL;
-}
 
 static struct security_operations capability_ops = {
 	.ptrace =			cap_ptrace,
 	.capget =			cap_capget,
 	.capset_check =			cap_capset_check,
 	.capset_set =			cap_capset_set,
-	.acct =				cap_acct,
 	.capable =			cap_capable,
-	.quotactl =			cap_quotactl,
-	.quota_on =			cap_quota_on,
 
-	.bprm_alloc_security =		cap_bprm_alloc_security,
-	.bprm_free_security =		cap_bprm_free_security,
 	.bprm_compute_creds =		cap_bprm_compute_creds,
 	.bprm_set_security =		cap_bprm_set_security,
-	.bprm_check_security =		cap_bprm_check_security,
-
-	.sb_alloc_security =		cap_sb_alloc_security,
-	.sb_free_security =		cap_sb_free_security,
-	.sb_statfs =			cap_sb_statfs,
-	.sb_mount =			cap_mount,
-	.sb_check_sb =			cap_check_sb,
-	.sb_umount =			cap_umount,
-	.sb_umount_close =		cap_umount_close,
-	.sb_umount_busy =		cap_umount_busy,
-	.sb_post_remount =		cap_post_remount,
-	.sb_post_mountroot =		cap_post_mountroot,
-	.sb_post_addmount =		cap_post_addmount,
-	.sb_pivotroot =			cap_pivotroot,
-	.sb_post_pivotroot =		cap_post_pivotroot,
-	
-	.inode_alloc_security =		cap_inode_alloc_security,
-	.inode_free_security =		cap_inode_free_security,
-	.inode_create =			cap_inode_create,
-	.inode_post_create =		cap_inode_post_create,
-	.inode_link =			cap_inode_link,
-	.inode_post_link =		cap_inode_post_link,
-	.inode_unlink =			cap_inode_unlink,
-	.inode_symlink =		cap_inode_symlink,
-	.inode_post_symlink =		cap_inode_post_symlink,
-	.inode_mkdir =			cap_inode_mkdir,
-	.inode_post_mkdir =		cap_inode_post_mkdir,
-	.inode_rmdir =			cap_inode_rmdir,
-	.inode_mknod =			cap_inode_mknod,
-	.inode_post_mknod =		cap_inode_post_mknod,
-	.inode_rename =			cap_inode_rename,
-	.inode_post_rename =		cap_inode_post_rename,
-	.inode_readlink =		cap_inode_readlink,
-	.inode_follow_link =		cap_inode_follow_link,
-	.inode_permission =		cap_inode_permission,
-	.inode_permission_lite =	cap_inode_permission_lite,
-	.inode_setattr =		cap_inode_setattr,
-	.inode_getattr =		cap_inode_getattr,
-	.inode_post_lookup =		cap_post_lookup,
-	.inode_delete =			cap_delete,
-	.inode_setxattr =		cap_inode_setxattr,
-	.inode_getxattr =		cap_inode_getxattr,
-	.inode_listxattr =		cap_inode_listxattr,
-	.inode_removexattr =		cap_inode_removexattr,
-	
-	.file_permission =		cap_file_permission,
-	.file_alloc_security =		cap_file_alloc_security,
-	.file_free_security =		cap_file_free_security,
-	.file_ioctl =			cap_file_ioctl,
-	.file_mmap =			cap_file_mmap,
-	.file_mprotect =		cap_file_mprotect,
-	.file_lock =			cap_file_lock,
-	.file_fcntl =			cap_file_fcntl,
-	.file_set_fowner =		cap_file_set_fowner,
-	.file_send_sigiotask =		cap_file_send_sigiotask,
-	.file_receive =			cap_file_receive,
 
-	.task_create =			cap_task_create,
-	.task_alloc_security =		cap_task_alloc_security,
-	.task_free_security =		cap_task_free_security,
-	.task_setuid =			cap_task_setuid,
 	.task_post_setuid =		cap_task_post_setuid,
-	.task_setgid =			cap_task_setgid,
-	.task_setpgid =			cap_task_setpgid,
-	.task_getpgid =			cap_task_getpgid,
-	.task_getsid =			cap_task_getsid,
-	.task_setgroups =		cap_task_setgroups,
-	.task_setnice =			cap_task_setnice,
-	.task_setrlimit =		cap_task_setrlimit,
-	.task_setscheduler =		cap_task_setscheduler,
-	.task_getscheduler =		cap_task_getscheduler,
-	.task_wait =			cap_task_wait,
-	.task_kill =			cap_task_kill,
-	.task_prctl =			cap_task_prctl,
 	.task_kmod_set_label =		cap_task_kmod_set_label,
 	.task_reparent_to_init =	cap_task_reparent_to_init,
-
-	.ipc_permission =		cap_ipc_permission,
-
-	.msg_queue_alloc_security =	cap_msg_queue_alloc_security,
-	.msg_queue_free_security =	cap_msg_queue_free_security,
-	
-	.shm_alloc_security =		cap_shm_alloc_security,
-	.shm_free_security =		cap_shm_free_security,
-	
-	.sem_alloc_security =		cap_sem_alloc_security,
-	.sem_free_security =		cap_sem_free_security,
-
-	.register_security =		cap_register,
-	.unregister_security =		cap_unregister,
 };
 
 #if defined(CONFIG_SECURITY_CAPABILITIES_MODULE)
===== security/dummy.c 1.10 vs edited =====
--- 1.10/security/dummy.c	Sun Nov 24 15:27:58 2002
+++ edited/security/dummy.c	Sat Nov 30 23:03:24 2002
@@ -122,55 +122,55 @@
 	return 0;
 }
 
-static int dummy_mount (char *dev_name, struct nameidata *nd, char *type,
-			unsigned long flags, void *data)
+static int dummy_sb_mount (char *dev_name, struct nameidata *nd, char *type,
+			   unsigned long flags, void *data)
 {
 	return 0;
 }
 
-static int dummy_check_sb (struct vfsmount *mnt, struct nameidata *nd)
+static int dummy_sb_check_sb (struct vfsmount *mnt, struct nameidata *nd)
 {
 	return 0;
 }
 
-static int dummy_umount (struct vfsmount *mnt, int flags)
+static int dummy_sb_umount (struct vfsmount *mnt, int flags)
 {
 	return 0;
 }
 
-static void dummy_umount_close (struct vfsmount *mnt)
+static void dummy_sb_umount_close (struct vfsmount *mnt)
 {
 	return;
 }
 
-static void dummy_umount_busy (struct vfsmount *mnt)
+static void dummy_sb_umount_busy (struct vfsmount *mnt)
 {
 	return;
 }
 
-static void dummy_post_remount (struct vfsmount *mnt, unsigned long flags,
-				void *data)
+static void dummy_sb_post_remount (struct vfsmount *mnt, unsigned long flags,
+				   void *data)
 {
 	return;
 }
 
 
-static void dummy_post_mountroot (void)
+static void dummy_sb_post_mountroot (void)
 {
 	return;
 }
 
-static void dummy_post_addmount (struct vfsmount *mnt, struct nameidata *nd)
+static void dummy_sb_post_addmount (struct vfsmount *mnt, struct nameidata *nd)
 {
 	return;
 }
 
-static int dummy_pivotroot (struct nameidata *old_nd, struct nameidata *new_nd)
+static int dummy_sb_pivotroot (struct nameidata *old_nd, struct nameidata *new_nd)
 {
 	return 0;
 }
 
-static void dummy_post_pivotroot (struct nameidata *old_nd, struct nameidata *new_nd)
+static void dummy_sb_post_pivotroot (struct nameidata *old_nd, struct nameidata *new_nd)
 {
 	return;
 }
@@ -303,12 +303,12 @@
 	return 0;
 }
 
-static void dummy_post_lookup (struct inode *ino, struct dentry *d)
+static void dummy_inode_post_lookup (struct inode *ino, struct dentry *d)
 {
 	return;
 }
 
-static void dummy_delete (struct inode *ino)
+static void dummy_inode_delete (struct inode *ino)
 {
 	return;
 }
@@ -529,12 +529,12 @@
 	return;
 }
 
-static int dummy_register (const char *name, struct security_operations *ops)
+static int dummy_register_security (const char *name, struct security_operations *ops)
 {
 	return -EINVAL;
 }
 
-static int dummy_unregister (const char *name, struct security_operations *ops)
+static int dummy_unregister_security (const char *name, struct security_operations *ops)
 {
 	return -EINVAL;
 }
@@ -558,16 +558,16 @@
 	.sb_alloc_security =		dummy_sb_alloc_security,
 	.sb_free_security =		dummy_sb_free_security,
 	.sb_statfs =			dummy_sb_statfs,
-	.sb_mount =			dummy_mount,
-	.sb_check_sb =			dummy_check_sb,
-	.sb_umount =			dummy_umount,
-	.sb_umount_close =		dummy_umount_close,
-	.sb_umount_busy =		dummy_umount_busy,
-	.sb_post_remount =		dummy_post_remount,
-	.sb_post_mountroot =		dummy_post_mountroot,
-	.sb_post_addmount =		dummy_post_addmount,
-	.sb_pivotroot =			dummy_pivotroot,
-	.sb_post_pivotroot =		dummy_post_pivotroot,
+	.sb_mount =			dummy_sb_mount,
+	.sb_check_sb =			dummy_sb_check_sb,
+	.sb_umount =			dummy_sb_umount,
+	.sb_umount_close =		dummy_sb_umount_close,
+	.sb_umount_busy =		dummy_sb_umount_busy,
+	.sb_post_remount =		dummy_sb_post_remount,
+	.sb_post_mountroot =		dummy_sb_post_mountroot,
+	.sb_post_addmount =		dummy_sb_post_addmount,
+	.sb_pivotroot =			dummy_sb_pivotroot,
+	.sb_post_pivotroot =		dummy_sb_post_pivotroot,
 	
 	.inode_alloc_security =		dummy_inode_alloc_security,
 	.inode_free_security =		dummy_inode_free_security,
@@ -591,8 +591,8 @@
 	.inode_permission_lite =	dummy_inode_permission_lite,
 	.inode_setattr =		dummy_inode_setattr,
 	.inode_getattr =		dummy_inode_getattr,
-	.inode_post_lookup =		dummy_post_lookup,
-	.inode_delete =			dummy_delete,
+	.inode_post_lookup =		dummy_inode_post_lookup,
+	.inode_delete =			dummy_inode_delete,
 	.inode_setxattr =		dummy_inode_setxattr,
 	.inode_getxattr =		dummy_inode_getxattr,
 	.inode_listxattr =		dummy_inode_listxattr,
@@ -641,7 +641,111 @@
 	.sem_alloc_security =		dummy_sem_alloc_security,
 	.sem_free_security =		dummy_sem_free_security,
 
-	.register_security =		dummy_register,
-	.unregister_security =		dummy_unregister,
+	.register_security =		dummy_register_security,
+	.unregister_security =		dummy_unregister_security,
 };
+
+#define set_to_dummy_if_null(ops, function)			\
+	do {							\
+		if (!ops->function)				\
+			ops->function = dummy_##function;	\
+	} while (0)
+
+void security_fixup_ops (struct security_operations *ops)
+{
+	set_to_dummy_if_null(ops, capget);
+	set_to_dummy_if_null(ops, ptrace);
+	set_to_dummy_if_null(ops, capget);
+	set_to_dummy_if_null(ops, capset_check);
+	set_to_dummy_if_null(ops, capset_set);
+	set_to_dummy_if_null(ops, acct);
+	set_to_dummy_if_null(ops, capable);
+	set_to_dummy_if_null(ops, quotactl);
+	set_to_dummy_if_null(ops, quota_on);
+	set_to_dummy_if_null(ops, bprm_alloc_security);
+	set_to_dummy_if_null(ops, bprm_free_security);
+	set_to_dummy_if_null(ops, bprm_compute_creds);
+	set_to_dummy_if_null(ops, bprm_set_security);
+	set_to_dummy_if_null(ops, bprm_check_security);
+	set_to_dummy_if_null(ops, sb_alloc_security);
+	set_to_dummy_if_null(ops, sb_free_security);
+	set_to_dummy_if_null(ops, sb_statfs);
+	set_to_dummy_if_null(ops, sb_mount);
+	set_to_dummy_if_null(ops, sb_check_sb);
+	set_to_dummy_if_null(ops, sb_umount);
+	set_to_dummy_if_null(ops, sb_umount_close);
+	set_to_dummy_if_null(ops, sb_umount_busy);
+	set_to_dummy_if_null(ops, sb_post_remount);
+	set_to_dummy_if_null(ops, sb_post_mountroot);
+	set_to_dummy_if_null(ops, sb_post_addmount);
+	set_to_dummy_if_null(ops, sb_pivotroot);
+	set_to_dummy_if_null(ops, sb_post_pivotroot);
+	set_to_dummy_if_null(ops, inode_alloc_security);
+	set_to_dummy_if_null(ops, inode_free_security);
+	set_to_dummy_if_null(ops, inode_create);
+	set_to_dummy_if_null(ops, inode_post_create);
+	set_to_dummy_if_null(ops, inode_link);
+	set_to_dummy_if_null(ops, inode_post_link);
+	set_to_dummy_if_null(ops, inode_unlink);
+	set_to_dummy_if_null(ops, inode_symlink);
+	set_to_dummy_if_null(ops, inode_post_symlink);
+	set_to_dummy_if_null(ops, inode_mkdir);
+	set_to_dummy_if_null(ops, inode_post_mkdir);
+	set_to_dummy_if_null(ops, inode_rmdir);
+	set_to_dummy_if_null(ops, inode_mknod);
+	set_to_dummy_if_null(ops, inode_post_mknod);
+	set_to_dummy_if_null(ops, inode_rename);
+	set_to_dummy_if_null(ops, inode_post_rename);
+	set_to_dummy_if_null(ops, inode_readlink);
+	set_to_dummy_if_null(ops, inode_follow_link);
+	set_to_dummy_if_null(ops, inode_permission);
+	set_to_dummy_if_null(ops, inode_permission_lite);
+	set_to_dummy_if_null(ops, inode_setattr);
+	set_to_dummy_if_null(ops, inode_getattr);
+	set_to_dummy_if_null(ops, inode_post_lookup);
+	set_to_dummy_if_null(ops, inode_delete);
+	set_to_dummy_if_null(ops, inode_setxattr);
+	set_to_dummy_if_null(ops, inode_getxattr);
+	set_to_dummy_if_null(ops, inode_listxattr);
+	set_to_dummy_if_null(ops, inode_removexattr);
+	set_to_dummy_if_null(ops, file_permission);
+	set_to_dummy_if_null(ops, file_alloc_security);
+	set_to_dummy_if_null(ops, file_free_security);
+	set_to_dummy_if_null(ops, file_ioctl);
+	set_to_dummy_if_null(ops, file_mmap);
+	set_to_dummy_if_null(ops, file_mprotect);
+	set_to_dummy_if_null(ops, file_lock);
+	set_to_dummy_if_null(ops, file_fcntl);
+	set_to_dummy_if_null(ops, file_set_fowner);
+	set_to_dummy_if_null(ops, file_send_sigiotask);
+	set_to_dummy_if_null(ops, file_receive);
+	set_to_dummy_if_null(ops, task_create);
+	set_to_dummy_if_null(ops, task_alloc_security);
+	set_to_dummy_if_null(ops, task_free_security);
+	set_to_dummy_if_null(ops, task_setuid);
+	set_to_dummy_if_null(ops, task_post_setuid);
+	set_to_dummy_if_null(ops, task_setgid);
+	set_to_dummy_if_null(ops, task_setpgid);
+	set_to_dummy_if_null(ops, task_getpgid);
+	set_to_dummy_if_null(ops, task_getsid);
+	set_to_dummy_if_null(ops, task_setgroups);
+	set_to_dummy_if_null(ops, task_setnice);
+	set_to_dummy_if_null(ops, task_setrlimit);
+	set_to_dummy_if_null(ops, task_setscheduler);
+	set_to_dummy_if_null(ops, task_getscheduler);
+	set_to_dummy_if_null(ops, task_wait);
+	set_to_dummy_if_null(ops, task_kill);
+	set_to_dummy_if_null(ops, task_prctl);
+	set_to_dummy_if_null(ops, task_kmod_set_label);
+	set_to_dummy_if_null(ops, task_reparent_to_init);
+	set_to_dummy_if_null(ops, ipc_permission);
+	set_to_dummy_if_null(ops, msg_queue_alloc_security);
+	set_to_dummy_if_null(ops, msg_queue_free_security);
+	set_to_dummy_if_null(ops, shm_alloc_security);
+	set_to_dummy_if_null(ops, shm_free_security);
+	set_to_dummy_if_null(ops, sem_alloc_security);
+	set_to_dummy_if_null(ops, sem_free_security);
+	set_to_dummy_if_null(ops, register_security);
+	set_to_dummy_if_null(ops, unregister_security);
+}
 
===== security/security.c 1.4 vs edited =====
--- 1.4/security/security.c	Thu Oct 17 13:21:20 2002
+++ edited/security/security.c	Sat Nov 30 23:01:07 2002
@@ -20,7 +20,9 @@
 
 #define SECURITY_SCAFFOLD_VERSION	"1.0.0"
 
-extern struct security_operations dummy_security_ops;	/* lives in dummy.c */
+/* things that live in dummy.c */
+extern struct security_operations dummy_security_ops;
+extern void security_fixup_ops (struct security_operations *ops);
 
 struct security_operations *security_ops;	/* Initialized to NULL */
 
@@ -45,7 +47,7 @@
 		} \
 	} while (0)
 
-static int inline verify (struct security_operations *ops)
+static int verify (struct security_operations *ops)
 {
 	int err;
 
@@ -59,11 +61,8 @@
 	/* Perform a little sanity checking on our inputs */
 	err = 0;
 
-	/* This first check scans the whole security_ops struct for
+	/* This check scans the whole security_ops struct for
 	 * missing structs or functions.
-	 *
-	 * (There is no further check now, but will leave as is until
-	 *  the lazy registration stuff is done -- JM).
 	 */
 	VERIFY_STRUCT(struct security_operations, ops, err);
 
@@ -106,6 +105,7 @@
  */
 int register_security (struct security_operations *ops)
 {
+	security_fixup_ops (ops);
 
 	if (verify (ops)) {
 		printk (KERN_INFO "%s could not verify "
@@ -162,6 +162,8 @@
  */
 int mod_reg_security (const char *name, struct security_operations *ops)
 {
+	security_fixup_ops (ops);
+
 	if (verify (ops)) {
 		printk (KERN_INFO "%s could not verify "
 			"security operations.\n", __FUNCTION__);

^ permalink raw reply	[flat|nested] 23+ messages in thread
* Re: [RFC] LSM fix for stupid "empty" functions
@ 2002-12-01 18:57 Adam J. Richter
  0 siblings, 0 replies; 23+ messages in thread
From: Adam J. Richter @ 2002-12-01 18:57 UTC (permalink / raw)
  To: linux-kernel
  Cc: crispin, greg, hallyn, hch, jmorris,
	olaf.dietsche#list.linux-kernel

On Sun, Dec 01, 2002, Greg Kroah-Hartmann wrote:
>On Sun, Dec 01, 2002 at 05:21:56PM +0000, Christoph Hellwig wrote:
>> On Sun, Dec 01, 2002 at 10:12:27AM -0800, Greg KH wrote:
>> > Does the kernel work if data structures are in ROM?  I would think that
>> > lots of variables in the kernel would have this problem :)
>> 
>> The nommu ports support .text in rom.
>
>But doesn't initialized variables live in .bss?  So we should be ok,
>right?

	Initialized writable variables live in .data.
	Initialized constant variables live in .rodata.
	"Uninitialized" variables live in .bss (initialized to zeros).

	You can also put a variable in a different section with the
gcc feature __attribute__((__section__("sectioname") )), as is done
for initdata and exitdata variables in include/linux/init.h.  A kernel
link script such as linux-2.5.50/arch/i386/vmlinux.ld.S then arranges
the different sections together according to which ones should
be writable, among other considerations.

	In general, which structures have to be allocated from
writable memory and which do not is a characteristic of individual
programming interfaces.  For example, most device drivers that embed a
struct device_driver must be in writable memory because the various
"bus type" registration functions usually fill in fields in the
embedded struct device_driver.  This has greatly eased migration to
struct device_driver.  An example of this is pci_register_driver
in linux-2.5.50/drivers/pci/pci-driver.c.

	Although it may be possible to eliminate much of this filling
in of struct device_driver fields by making future drivers initialize
these fields directly, it will probably still be optimal for some bus
types to use this technique to consolidate certain facilities that
are specific to one bus type, but common across drivers within that
bus type.

	For example, there is a common way to determine what IO and
memory ranges a PCI device may need from its configuration registers,
so I would like to add an optional mask to tell
pci_device_{probe,remove} to handle the associated request_region()
calls and failure branches.  This could simplify PCI drivers a bit,
because current Linux drivers have a lot of rarely tested resource
allocation failure branches, and they tend to get more complicated
when they involve potentially unwinding a bunch of allocations.  Also,
this bookkeeping might be made obselete by other hotplug PCI support,
in which case we change the code in one place to skip it.  On the
other hand, pushing this facility up to the generic device layer might
add more complexity than it would save (although that would be worth
exploring as a subsequent refinement).  So, there may continue to be
an advantage to having some bus-specific wrapper functions.

	Also, having mybus_regsiter_device() fill in these function
may simplify future modification, which is probably more true of
Greg's security module changes.  You may be able to add operations
without needing to modify every module to include dummy function for
the new operations.

	By the way, I'm not that strong an advocate of this.  I'm just
trying to explain the trade-off.  I suspect that it will be beneficial
to slim down many of the bus-specific layers in the future.

Adam J. Richter     __     ______________   575 Oroville Road
adam@yggdrasil.com     \ /                  Milpitas, California 95035
+1 408 309-6081         | g g d r a s i l   United States of America
                         "Free Software For The Rest Of Us."

^ permalink raw reply	[flat|nested] 23+ messages in thread
end of thread, other threads:[~2002-12-05  0:02 UTC | newest]

Thread overview: 23+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2002-12-01  8:30 [RFC] LSM fix for stupid "empty" functions Greg KH
2002-12-01  8:17 ` Crispin Cowan
2002-12-01 17:49   ` Greg KH
2002-12-01 16:59 ` Olaf Dietsche
2002-12-01 18:12   ` Greg KH
2002-12-01 17:21     ` Christoph Hellwig
2002-12-01 18:26       ` Greg KH
2002-12-03  2:37         ` Dragan Stancevic
2002-12-03 16:01           ` Greg KH
2002-12-03 15:14             ` Dragan Stancevic
2002-12-01 17:46     ` James Morris
2002-12-01 18:46       ` Olaf Dietsche
2002-12-01 20:05         ` Greg KH
2002-12-01 19:25       ` Greg KH
2002-12-02  2:00         ` James Morris
2002-12-02  6:57           ` Greg KH
2002-12-03  8:04             ` James Morris
2002-12-04  0:13 ` [RFC] LSM fix for stupid "empty" functions - take 2 Greg KH
2002-12-04  8:14   ` Chris Wright
2002-12-04 23:00     ` Greg KH
2002-12-04 23:44       ` Chris Wright
2002-12-05  0:09   ` James Morris
  -- strict thread matches above, loose matches on Subject: below --
2002-12-01 18:57 [RFC] LSM fix for stupid "empty" functions Adam J. Richter

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