Commit 1c204914 authored by Christophe Leroy's avatar Christophe Leroy Committed by Thomas Gleixner
Browse files

scm: Convert put_cmsg() to scoped user access 



Replace the open coded implementation with the scoped user access guard.

That also corrects the imbalance between masked_user_access_begin() and
user_write_access_end(), which would affect PowerPC when it gains masked
user access support.

No functional change intended.

[ tglx: Amend change log ]

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/793219313f641eda09a892d06768d2837246bf9f.1763396724.git.christophe.leroy@csgroup.eu
parent 803abedb

net/core/scm.c

+7 −13
Original line number Diff line number Diff line
@@ -273,17 +273,13 @@ int put_cmsg(struct msghdr * msg, int level, int type, int len, void *data) 


		check_object_size(data, cmlen - sizeof(*cm), true);



		if (can_do_masked_user_access())

			cm = masked_user_access_begin(cm);

		else if (!user_write_access_begin(cm, cmlen))

			goto efault;



		unsafe_put_user(cmlen, &cm->cmsg_len, efault_end);

		unsafe_put_user(level, &cm->cmsg_level, efault_end);

		unsafe_put_user(type, &cm->cmsg_type, efault_end);

		scoped_user_write_access_size(cm, cmlen, efault) {

			unsafe_put_user(cmlen, &cm->cmsg_len, efault);

			unsafe_put_user(level, &cm->cmsg_level, efault);

			unsafe_put_user(type, &cm->cmsg_type, efault);

			unsafe_copy_to_user(CMSG_USER_DATA(cm), data,

				    cmlen - sizeof(*cm), efault_end);

		user_write_access_end();

					    cmlen - sizeof(*cm), efault);

		}

	} else {

		struct cmsghdr *cm = msg->msg_control;
@@ -301,8 +297,6 @@ int put_cmsg(struct msghdr * msg, int level, int type, int len, void *data) 
	msg->msg_controllen -= cmlen;

	return 0;



efault_end:

	user_write_access_end();

efault:

	return -EFAULT;

}