From 6e6823d17b157f185be09f4c70181299f9273f0b Mon Sep 17 00:00:00 2001 From: Torben Hohn Date: Thu, 3 Mar 2011 18:26:14 +0100 Subject: posix-clocks: Check write permissions in posix syscalls pc_clock_settime() and pc_clock_adjtime() do not check whether the fd was opened in write mode, so a clock can be set with a read only fd. [ tglx: We deliberately do not return -EPERM as we want this to be distingushable from the capability based permission check ] Signed-off-by: Torben Hohn LKML-Reference: <1299173174-348-4-git-send-email-torbenh@gmx.de> Cc: Richard Cochran Cc: John Stultz Cc: Thomas Gleixner --- kernel/time/posix-clock.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c index 04498cbf6002..25028dd4fa18 100644 --- a/kernel/time/posix-clock.c +++ b/kernel/time/posix-clock.c @@ -287,11 +287,16 @@ static int pc_clock_adjtime(clockid_t id, struct timex *tx) if (err) return err; + if ((cd.fp->f_mode & FMODE_WRITE) == 0) { + err = -EACCES; + goto out; + } + if (cd.clk->ops.clock_adjtime) err = cd.clk->ops.clock_adjtime(cd.clk, tx); else err = -EOPNOTSUPP; - +out: put_clock_desc(&cd); return err; @@ -344,11 +349,16 @@ static int pc_clock_settime(clockid_t id, const struct timespec *ts) if (err) return err; + if ((cd.fp->f_mode & FMODE_WRITE) == 0) { + err = -EACCES; + goto out; + } + if (cd.clk->ops.clock_settime) err = cd.clk->ops.clock_settime(cd.clk, ts); else err = -EOPNOTSUPP; - +out: put_clock_desc(&cd); return err; -- cgit v1.2.3