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| author | Jakub Kicinski <kuba@kernel.org> | 2021-06-15 01:24:05 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-23 15:41:26 +0300 |
| commit | 3daa97817aa818ea783e6edcf4e9d9c47b6c330f (patch) | |
| tree | 79b63c8e62bd7cbc29643254ee1e224a212aa40f /include/linux | |
| parent | 26b8d10703a9be45d6097946b2b4011f7dd2c56f (diff) | |
| download | linux-3daa97817aa818ea783e6edcf4e9d9c47b6c330f.tar.xz | |
ptp: improve max_adj check against unreasonable values
[ Upstream commit 475b92f932168a78da8109acd10bfb7578b8f2bb ]
Scaled PPM conversion to PPB may (on 64bit systems) result
in a value larger than s32 can hold (freq/scaled_ppm is a long).
This means the kernel will not correctly reject unreasonably
high ->freq values (e.g. > 4294967295ppb, 281474976645 scaled PPM).
The conversion is equivalent to a division by ~66 (65.536),
so the value of ppb is always smaller than ppm, but not small
enough to assume narrowing the type from long -> s32 is okay.
Note that reasonable user space (e.g. ptp4l) will not use such
high values, anyway, 4289046510ppb ~= 4.3x, so the fix is
somewhat pedantic.
Fixes: d39a743511cd ("ptp: validate the requested frequency adjustment.")
Fixes: d94ba80ebbea ("ptp: Added a brand new class driver for ptp clocks.")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/ptp_clock_kernel.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h index 93cc4f1d444a..874f7e73ed01 100644 --- a/include/linux/ptp_clock_kernel.h +++ b/include/linux/ptp_clock_kernel.h @@ -218,7 +218,7 @@ extern int ptp_clock_index(struct ptp_clock *ptp); * @ppm: Parts per million, but with a 16 bit binary fractional field */ -extern s32 scaled_ppm_to_ppb(long ppm); +extern long scaled_ppm_to_ppb(long ppm); /** * ptp_find_pin() - obtain the pin index of a given auxiliary function |