Hi, Christoph, Christoph Hellwig <hch@xxxxxx> writes: > On Mon, Jan 15, 2018 at 09:53:10AM +0100, Christoph Hellwig wrote: >> > pselect, as an example, crams the sigmask and size together. Why not >> > just do that? libaio can take care of setting that up. >> >> Yes, I could try that. It's just another double indirection for no >> good reason. > > I cna't get this to work - for some reason I always end up with a NULL > sigmask in the kernel. Nevermind that it leads to really crap code > generation. I guess for select the latter doesn't matter too much as > everyone sane uses ppoll anyway. I'd be willing to bet the issue is in your io_syscall6 implementation. You pass in arg5 where arg6 should be used. Don't feel bad, it took me the better part of today to figure that out. :) Here's an incremental diff on top of what you've posted. Feel free to fold it into your patch (and format however you like). You can find the libaio changes in my 'aio-poll' branch: https://pagure.io/libaio/commits/aio-poll These changes were run through the libaio test harness, 64 bit and 32 bit, so the compat system call was tested. Cheers, Jeff diff --git a/fs/aio.c b/fs/aio.c index 57a4e8d..c6d67d0 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1991,9 +1991,11 @@ static long do_io_getevents(aio_context_t ctx_id, long, nr, struct io_event __user *, events, struct timespec __user *, timeout, - const sigset_t __user *, sigmask) + void __user *, sigmask) { sigset_t ksigmask, sigsaved; + size_t sigsetsize = 0; + sigset_t __user *up = NULL; struct timespec64 ts; int ret; @@ -2001,8 +2003,18 @@ static long do_io_getevents(aio_context_t ctx_id, return -EFAULT; if (sigmask) { - if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) + if (!access_ok(VERIFY_READ, sigmask, + sizeof(void *) + sizeof(size_t)) || + __get_user(up, (sigset_t __user * __user *)sigmask) || + __get_user(sigsetsize, + (size_t __user *)(sigmask + sizeof(void *)))) return -EFAULT; + + if (sigsetsize != sizeof(sigset_t)) + return -EINVAL; + if (copy_from_user(&ksigmask, up, sizeof(ksigmask))) + return -EFAULT; + sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP)); sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); } @@ -2049,8 +2061,11 @@ static long do_io_getevents(aio_context_t ctx_id, compat_long_t, nr, struct io_event __user *, events, struct compat_timespec __user *, timeout, - const compat_sigset_t __user *, sigmask) + void __user *, sig) { + compat_size_t sigsetsize = 0; + compat_sigset_t __user *sigmask; + compat_uptr_t up = 0; sigset_t ksigmask, sigsaved; struct timespec64 t; int ret; @@ -2058,8 +2073,17 @@ static long do_io_getevents(aio_context_t ctx_id, if (timeout && compat_get_timespec64(&t, timeout)) return -EFAULT; - if (sigmask) { - if (get_compat_sigset(&ksigmask, sigmask)) + if (sig) { + if (!access_ok(VERIFY_READ, sig, + sizeof(compat_uptr_t) + sizeof(compat_size_t)) || + __get_user(up, (compat_uptr_t __user *)sig) || + __get_user(sigsetsize, + (compat_size_t __user *)(sig + sizeof(up)))) + return -EFAULT; + + if (sigsetsize != sizeof(compat_sigset_t)) + return -EINVAL; + if (get_compat_sigset(&ksigmask, compat_ptr(up))) return -EFAULT; sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP)); sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); diff --git a/include/linux/compat.h b/include/linux/compat.h index a4cda98..32412f8 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -541,7 +541,7 @@ asmlinkage long compat_sys_io_pgetevents(compat_aio_context_t ctx_id, compat_long_t nr, struct io_event __user *events, struct compat_timespec __user *timeout, - const compat_sigset_t __user *sigmask); + void __user *sigmask); asmlinkage long compat_sys_io_submit(compat_aio_context_t ctx_id, int nr, u32 __user *iocb); asmlinkage long compat_sys_mount(const char __user *dev_name, diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 3bc9a13..bc79026 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -544,7 +544,7 @@ asmlinkage long sys_io_pgetevents(aio_context_t ctx_id, long nr, struct io_event __user *events, struct timespec __user *timeout, - const sigset_t __user *sigmask); + void __user *sigmask); asmlinkage long sys_io_submit(aio_context_t, long, struct iocb __user * __user *); asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb,
