path: root/include
diff options
authorJakub Kicinski <>2021-06-14 15:24:05 -0700
committerDavid S. Miller <>2021-06-15 10:59:46 -0700
commit475b92f932168a78da8109acd10bfb7578b8f2bb (patch)
tree1659ca2f045d8cc6295dae645c844e3228326494 /include
parent2214fb53006e6cfa6371b706070cb99794c68c3b (diff)
ptp: improve max_adj check against unreasonable values
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 <> Acked-by: Richard Cochran <> Signed-off-by: David S. Miller <>
Diffstat (limited to 'include')
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index 0d47fd33b228..51d7f1b8b32a 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -235,7 +235,7 @@ 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