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| author | Sasha Levin <sasha.levin@oracle.com> | 2014-12-03 19:25:05 -0500 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2015-04-14 17:33:51 +0800 |
| commit | 3f6d9b62622ce5dbb870160cb3da5f8bfc87adee (patch) | |
| tree | 91e676b714b14bd2b06f4ec68bd892963a966961 | |
| parent | 370375c0a447eefedc19e872e5137eeff47162f2 (diff) | |
| download | lwn-3f6d9b62622ce5dbb870160cb3da5f8bfc87adee.tar.gz lwn-3f6d9b62622ce5dbb870160cb3da5f8bfc87adee.zip | |
time: adjtimex: Validate the ADJ_FREQUENCY values
commit 5e5aeb4367b450a28f447f6d5ab57d8f2ab16a5f upstream.
Verify that the frequency value from userspace is valid and makes sense.
Unverified values can cause overflows later on.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
[jstultz: Fix up bug for negative values and drop redunent cap check]
Signed-off-by: John Stultz <john.stultz@linaro.org>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
| -rw-r--r-- | kernel/time/ntp.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 8b707100286b..7666b24ca9ab 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -660,6 +660,13 @@ int do_adjtimex(struct timex *txc) return result; } + if (txc->modes & ADJ_FREQUENCY) { + if (LONG_MIN / PPM_SCALE > txc->freq) + return -EINVAL; + if (LONG_MAX / PPM_SCALE < txc->freq) + return -EINVAL; + } + getnstimeofday(&ts); spin_lock_irq(&ntp_lock); |