From: Sasha Levin <sasha.le...@oracle.com>
3.4.107-rc1 review patch. If anyone has any objections, please let me know.
------------------
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 <t...@linutronix.de>
Cc: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Sasha Levin <sasha.le...@oracle.com>
[jstultz: Fix up bug for negative values and drop redunent cap check]
Signed-off-by: John Stultz <john.stu...@linaro.org>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lize...@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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