posix-clocks: Check write permissions in posix syscalls (6e6823d1) · Commits · 戴 / test

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 <torbenh@gmx.de> LKML-Reference: <1299173174-348-4-git-send-email-torbenh@gmx.de> Cc: Richard Cochran <richard.cochran@omicron.at> Cc: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de>

kernel/time/posix-clock.c

+12 −2

Original line number	Diff line number	Diff line
		@@ -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;

Admin message