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| author | Jakub Kicinski <kuba@kernel.org> | 2021-06-15 01:24:05 +0300 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2021-06-30 15:48:19 +0300 |
| commit | cee0a9c1826bebd7c2578ad0dcff06eb68868069 (patch) | |
| tree | 4a36ee138eabcba3a25a03496bd63b8c1788cddc /include | |
| parent | b5200624e643bb4cf65eb3b6d9bf36fc11982669 (diff) | |
| download | linux-cee0a9c1826bebd7c2578ad0dcff06eb68868069.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')
| -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 40ea83fcfdd5..99c3f4ee938e 100644 --- a/include/linux/ptp_clock_kernel.h +++ b/include/linux/ptp_clock_kernel.h @@ -210,7 +210,7 @@ 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 |