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| author |   Nick Desaulniers <nick.desaulniers@gmail.com> | 2017-12-28 22:11:36 -0500 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2018-01-04 14:57:10 +0100 |
| commit | 29f1b2b0fecfae69e31833836f1da3136696eee5 (patch) | |
| tree | 4c299cbdc55a3cc3236e8ef3cc80e6af51ee4a57 /kernel/time/posix-clock.c | |
| parent | Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (diff) | |
| download | linux-dev-29f1b2b0fecfae69e31833836f1da3136696eee5.tar.xz linux-dev-29f1b2b0fecfae69e31833836f1da3136696eee5.zip | |
posix-timers: Prevent UB from shifting negative signed value
Shifting a negative signed number is undefined behavior. Looking at the
macros MAKE_PROCESS_CPUCLOCK and FD_TO_CLOCKID, it seems that the
subexpression:
(~(clockid_t) (pid) << 3)
where clockid_t resolves to a signed int, which once negated, is
undefined behavior to shift the value of if the results thus far are
negative.
It was further suggested to make these macros into inline functions.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-kselftest@vger.kernel.org
Cc: Shuah Khan <shuah@kernel.org>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Link: https://lkml.kernel.org/r/1514517100-18051-1-git-send-email-nick.desaulniers@gmail.com
Diffstat (limited to 'kernel/time/posix-clock.c')
| -rw-r--r-- | kernel/time/posix-clock.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c index 17cdc554c9fe..cc91d90abd84 100644 --- a/kernel/time/posix-clock.c +++ b/kernel/time/posix-clock.c @@ -216,7 +216,7 @@ struct posix_clock_desc { static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd) { - struct file *fp = fget(CLOCKID_TO_FD(id)); + struct file *fp = fget(clockid_to_fd(id)); int err = -EINVAL; if (!fp) |