Messages in this thread | | | Date | Thu, 19 Feb 2015 16:15:08 -0500 (EST) | Subject | Re: [PATCH] net: compat: Ignore MSG_CMSG_COMPAT in compat_sys_{send,recv}msg | From | David Miller <> |
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From: Catalin Marinas <catalin.marinas@arm.com> Date: Thu, 12 Feb 2015 17:32:18 +0000
> On Thu, Feb 12, 2015 at 04:41:24PM +0000, David Miller wrote: >> Setting MSG_* bits that aren't supported by the protocol in any way >> gives undefined semantics. You may get an error, it may be silently >> ignored, etc. > > From the sendmsg(2) man page, if some bit in the flags is inappropriate > for the socket type, it should return -EOPNOTSUPP. But I can't tell > whether it refers only to bits which are defined (for other socket > types) or just any bit. The test itself checks for -EOPNOTSUPP but it > gets -EINVAL instead, hence the failure being reported.
Thanks for thinking about this a bit more. Yes, -EINVAL is probably not the thing we should return in this situation.
>> I'm not applying this, sorry. > > What I'm after is consistency between the native 32-bit kernel and the > compat layer on 64-bit. On the former, bit 31 is silently ignored, on > the latter it reports -EINVAL. > > We could as well do something like below but we end up with unnecessary > flags check on 32-bit. The question is whether such change would be > considered a 32-bit user ABI breakage.
Ok, after some further consideration I like your original patch.
If 32-bit ignores the value, 64-bit should too. So just mask it out.
Please resubmit your original patch, I'll apply it, thanks!
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