| From | lizf@kernel ... | Subject | [PATCH 3.4 089/176] time: adjtimex: Validate the ADJ_FREQUENCY values | Date | Thu, 9 Apr 2015 16:45:37 +0800 |
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From: Sasha Levin <sasha.levin@oracle.com>
3.4.107-rc1 review patch. If anyone has any objections, please let me know.
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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> --- kernel/time/ntp.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 8b70710..7666b24 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); -- 1.9.1
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