path: root/drivers
diff options
authorJacob Keller <>2019-09-25 19:28:19 -0700
committerDavid S. Miller <>2019-09-27 20:25:32 +0200
commit2df4de1681767df900e15e34195bbf7dc1b23e06 (patch)
tree1ded2106e3e0ff1cf96b4ec30b43b17a8516ea9f /drivers
parent991ad2b24da2fa7b4ba9775ca1fed2d660d54ab0 (diff)
ptp: correctly disable flags on old ioctls
Commit 415606588c61 ("PTP: introduce new versions of IOCTLs", 2019-09-13) introduced new versions of the PTP ioctls which actually validate that the flags are acceptable values. As part of this, it cleared the flags value using a bitwise and+negation, in an attempt to prevent the old ioctl from accidentally enabling new features. This is incorrect for a couple of reasons. First, it results in accidentally preventing previously working flags on the request ioctl. By clearing the "valid" flags, we now no longer allow setting the enable, rising edge, or falling edge flags. Second, if we add new additional flags in the future, they must not be set by the old ioctl. (Since the flag wasn't checked before, we could potentially break userspace programs which sent garbage flag data. The correct way to resolve this is to check for and clear all but the originally valid flags. Create defines indicating which flags are correctly checked and interpreted by the original ioctls. Use these to clear any bits which will not be correctly interpreted by the original ioctls. In the future, new flags must be added to the VALID_FLAGS macros, but *not* to the V1_VALID_FLAGS macros. In this way, new features may be exposed over the v2 ioctls, but without breaking previous userspace which happened to not clear the flags value properly. The old ioctl will continue to behave the same way, while the new ioctl gains the benefit of using the flags fields. Cc: Richard Cochran <> Cc: Felipe Balbi <> Cc: David S. Miller <> Cc: Christopher Hall <> Signed-off-by: Jacob Keller <> Acked-by: Richard Cochran <> Signed-off-by: David S. Miller <>
Diffstat (limited to 'drivers')
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 9c18476d8d10..67d0199840fd 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -155,7 +155,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
err = -EINVAL;
} else if (cmd == PTP_EXTTS_REQUEST) {
- req.extts.flags &= ~PTP_EXTTS_VALID_FLAGS;
+ req.extts.flags &= PTP_EXTTS_V1_VALID_FLAGS;
req.extts.rsv[0] = 0;
req.extts.rsv[1] = 0;
@@ -184,7 +184,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
err = -EINVAL;
} else if (cmd == PTP_PEROUT_REQUEST) {
- req.perout.flags &= ~PTP_PEROUT_VALID_FLAGS;
+ req.perout.flags &= PTP_PEROUT_V1_VALID_FLAGS;
req.perout.rsv[0] = 0;
req.perout.rsv[1] = 0;
req.perout.rsv[2] = 0;