From 5611f55ee4df70d947bf239c587e742efdab028b Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Tue, 24 Apr 2018 20:39:16 -0500 Subject: [PATCH] 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: "Eric W. Biederman" --- fs/signalfd.c | 56 ++++++++++++++++++++++++++------------------------- 1 file changed, 29 insertions(+), 27 deletions(-) diff --git a/fs/signalfd.c b/fs/signalfd.c index ff302bf50be4..31e960209a08 100644 --- a/fs/signalfd.c +++ b/fs/signalfd.c @@ -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,