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Commit 5611f55e authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

signal/signalfd: Remove __put_user from signalfd_copyinfo 



Put a signalfd_siginfo structure on the stack fully initializae
it and then copy it to userspace.

The code is a little less wordy, and this avoids a long series
of the somewhat costly __put_user calls.

Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 91810105

fs/signalfd.c

+29 −27
Original line number Diff line number Diff line
@@ -81,41 +81,41 @@ static __poll_t signalfd_poll(struct file *file, poll_table *wait) 
static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,

			     siginfo_t const *kinfo)

{

	long err;

	struct signalfd_siginfo new;



	BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128);



	/*

	 * Unused members should be zero ...

	 */

	err = __clear_user(uinfo, sizeof(*uinfo));

	memset(&new, 0, sizeof(new));



	/*

	 * If you change siginfo_t structure, please be sure

	 * this code is fixed accordingly.

	 */

	err |= __put_user(kinfo->si_signo, &uinfo->ssi_signo);

	err |= __put_user(kinfo->si_errno, &uinfo->ssi_errno);

	err |= __put_user(kinfo->si_code, &uinfo->ssi_code);

	new.ssi_signo = kinfo->si_signo;

	new.ssi_errno = kinfo->si_errno;

	new.ssi_code  = kinfo->si_code;

	switch (siginfo_layout(kinfo->si_signo, kinfo->si_code)) {

	case SIL_KILL:

		err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);

		err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);

		new.ssi_pid = kinfo->si_pid;

		new.ssi_uid = kinfo->si_uid;

		break;

	case SIL_TIMER:

		 err |= __put_user(kinfo->si_tid, &uinfo->ssi_tid);

		 err |= __put_user(kinfo->si_overrun, &uinfo->ssi_overrun);

		 err |= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);

		 err |= __put_user(kinfo->si_int, &uinfo->ssi_int);

		new.ssi_tid = kinfo->si_tid;

		new.ssi_overrun = kinfo->si_overrun;

		new.ssi_ptr = (long) kinfo->si_ptr;

		new.ssi_int = kinfo->si_int;

		break;

	case SIL_POLL:

		err |= __put_user(kinfo->si_band, &uinfo->ssi_band);

		err |= __put_user(kinfo->si_fd, &uinfo->ssi_fd);

		new.ssi_band = kinfo->si_band;

		new.ssi_fd   = kinfo->si_fd;

		break;

	case SIL_FAULT:

		err |= __put_user((long) kinfo->si_addr, &uinfo->ssi_addr);

		new.ssi_addr = (long) kinfo->si_addr;

#ifdef __ARCH_SI_TRAPNO

		err |= __put_user(kinfo->si_trapno, &uinfo->ssi_trapno);

		new.ssi_trapno = kinfo->si_trapno;

#endif

		/*

		 * Other callers might not initialize the si_lsb field,
@@ -124,29 +124,31 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo, 
		if (kinfo->si_signo == SIGBUS &&

		    ((kinfo->si_code == BUS_MCEERR_AR) ||

		     (kinfo->si_code == BUS_MCEERR_AO)))

			err |= __put_user((short) kinfo->si_addr_lsb,

					  &uinfo->ssi_addr_lsb);

			new.ssi_addr_lsb = (short) kinfo->si_addr_lsb;

		break;

	case SIL_CHLD:

		err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);

		err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);

		err |= __put_user(kinfo->si_status, &uinfo->ssi_status);

		err |= __put_user(kinfo->si_utime, &uinfo->ssi_utime);

		err |= __put_user(kinfo->si_stime, &uinfo->ssi_stime);

		new.ssi_pid    = kinfo->si_pid;

		new.ssi_uid    = kinfo->si_uid;

		new.ssi_status = kinfo->si_status;

		new.ssi_utime  = kinfo->si_utime;

		new.ssi_stime  = kinfo->si_stime;

		break;

	case SIL_RT:

	default:

		/*

		 * This case catches also the signals queued by sigqueue().

		 */

		err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);

		err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);

		err |= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);

		err |= __put_user(kinfo->si_int, &uinfo->ssi_int);

		new.ssi_pid = kinfo->si_pid;

		new.ssi_uid = kinfo->si_uid;

		new.ssi_ptr = (long) kinfo->si_ptr;

		new.ssi_int = kinfo->si_int;

		break;

	}



	return err ? -EFAULT: sizeof(*uinfo);

	if (copy_to_user(uinfo, &new, sizeof(struct signalfd_siginfo)))

		return -EFAULT;



	return sizeof(*uinfo);

}



static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, siginfo_t *info,