Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag
flat view
From: Al Viro <viro@zeniv.linux.org.uk>
Date: 2020-09-20 18:12:26
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io-uring, keyrings, linux-arch, linux-block, linux-fsdevel, linux-mips, linux-mm, linux-s390, linux-scsi, linux-security-module, linuxppc-dev, lkml, netdev, sparclinux
On Sun, Sep 20, 2020 at 09:59:36AM -0700, Andy Lutomirski wrote:
As one example, look at __sys_setsockopt(). It's called for the native and compat versions, and it contains an in_compat_syscall() check. (This particularly check looks dubious to me, but that's another story.) If this were to be done with equivalent semantics without a separate COMPAT_DEFINE_SYSCALL and without in_compat_syscall(), there would need to be some indication as to whether this is compat or native setsockopt. There are other setsockopt implementations in the net stack with more legitimate-seeming uses of in_compat_syscall() that would need some other mechanism if in_compat_syscall() were to go away. setsockopt is (I hope!) out of scope for io_uring, but the situation isn't fundamentally different from read and write.
Except that setsockopt() had that crap very widespread; for read() and write() those are very rare exceptions. Andy, please RTFS. Or dig through archives. The situation with setsockopt() is *NOT* a good thing - it's (probably) the least of the evils. The last thing we need is making that the norm. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel