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authorTorben Hohn <torbenh@gmx.de>2011-03-03 18:26:14 +0100
committerThomas Gleixner <tglx@linutronix.de>2011-03-12 21:27:07 +0100
commit6e6823d17b157f185be09f4c70181299f9273f0b (patch)
tree8a9009e2d54955c1a9c5a033493c8668915d09f8 /kernel
parenta9e7acfff0a279792918b7b0de74106e576e9988 (diff)
downloadlinux-6e6823d17b157f185be09f4c70181299f9273f0b.tar.bz2
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 <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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time/posix-clock.c14
1 files changed, 12 insertions, 2 deletions
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;