Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH] time: adjtimex: validate the ADJ_FREQUENCY case | Date | Wed, 3 Dec 2014 19:25:05 -0500 |
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Verify that the frequency value from userspace is valid and makes sense.
Unverified values can cause overflows later on.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com> --- kernel/time/ntp.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 87a346f..54828cf 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -633,6 +633,15 @@ int ntp_validate_timex(struct timex *txc) if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME))) return -EPERM; + if (txc->modes & ADJ_FREQUENCY) { + if (!capable(CAP_SYS_TIME)) + return -EPERM; + if (txc->freq < 0) + return -EINVAL; + if (LONG_MAX / PPM_SCALE < txc->freq) + return -EINVAL; + } + return 0; } -- 1.7.10.4
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