wireguard-linux/arch/x86/entry/syscalls, branch jd/unified-crypt-queue

x86/entry/32: Use IA32-specific wrappers for syscalls taking 64-bit arguments

2020-03-21T15:03:24Z

For the 32-bit syscall interface, 64-bit arguments (loff_t) are passed via a pair of 32-bit registers. These register pairs end up in consecutive stack slots, which matches the C ABI for 64-bit arguments. But when accessing the registers directly from pt_regs, the wrapper needs to manually reassemble the 64-bit value. These wrappers already exist for 32-bit compat, so make them available to 32-bit native in preparation for enabling pt_regs-based syscalls. Signed-off-by: Brian Gerst Signed-off-by: Thomas Gleixner Reviewed-by: Dominik Brodowski Link: https://lkml.kernel.org/r/20200313195144.164260-16-brgerst@gmail.com

x86/entry/32: Rename 32-bit specific syscalls

2020-03-21T15:03:23Z

Rename the syscalls that only exist for 32-bit from x86_* to ia32_* to make it clear they are for 32-bit only. Also rename the functions to match the syscall name. Signed-off-by: Brian Gerst Signed-off-by: Thomas Gleixner Reviewed-by: Dominik Brodowski Link: https://lkml.kernel.org/r/20200313195144.164260-15-brgerst@gmail.com

x86/entry/32: Clean up syscall_32.tbl

2020-03-21T15:03:23Z

After removal of the __ia32_ prefix, remove compat entries that are now identical to the native entry. Converted with this script and fixing up whitespace: while read nr abi name entry compat; do if [ "${nr:0:1}" = "#" ]; then echo $nr $abi $name $entry $compat continue fi if [ "$entry" = "$compat" ]; then compat="" fi echo "$nr $abi $name $entry $compat" done Signed-off-by: Brian Gerst Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200313195144.164260-14-brgerst@gmail.com

x86/entry: Remove ABI prefixes from functions in syscall tables

2020-03-21T15:03:23Z

Move the ABI prefixes to the __SYSCALL_[abi]() macros. This allows removal of the need to strip the prefix for UML. Signed-off-by: Brian Gerst Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200313195144.164260-13-brgerst@gmail.com

x86/entry/64: Add __SYSCALL_COMMON()

2020-03-21T15:03:22Z

Add a __SYSCALL_COMMON() macro to the syscall table, which simplifies syscalltbl.sh. Signed-off-by: Brian Gerst Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200313195144.164260-12-brgerst@gmail.com

x86/entry: Remove syscall qualifier support

2020-03-21T15:03:22Z

Syscall qualifier support is no longer needed. Signed-off-by: Brian Gerst Signed-off-by: Thomas Gleixner Reviewed-by: Dominik Brodowski Link: https://lkml.kernel.org/r/20200313195144.164260-11-brgerst@gmail.com

x86/entry/64: Remove ptregs qualifier from syscall table

2020-03-21T15:03:21Z

Now that the fast syscall path is removed, the ptregs qualifier is unused. Signed-off-by: Brian Gerst Signed-off-by: Thomas Gleixner Reviewed-by: Dominik Brodowski Link: https://lkml.kernel.org/r/20200313195144.164260-10-brgerst@gmail.com

x86/entry: Move max syscall number calculation to syscallhdr.sh

2020-03-21T15:03:21Z

Instead of using an array in asm-offsets to calculate the max syscall number, calculate it when writing out the syscall headers. Signed-off-by: Brian Gerst Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200313195144.164260-9-brgerst@gmail.com

x86/entry/64: Use syscall wrappers for x32_rt_sigreturn

2020-03-21T15:03:20Z

Add missing syscall wrapper for x32_rt_sigreturn(). Signed-off-by: Brian Gerst Signed-off-by: Thomas Gleixner Reviewed-by: Dominik Brodowski Reviewed-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20200313195144.164260-6-brgerst@gmail.com

Merge tag 'threads-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

2020-01-30T03:38:34Z

Pull thread management updates from Christian Brauner: "Sargun Dhillon over the last cycle has worked on the pidfd_getfd() syscall. This syscall allows for the retrieval of file descriptors of a process based on its pidfd. A task needs to have ptrace_may_access() permissions with PTRACE_MODE_ATTACH_REALCREDS (suggested by Oleg and Andy) on the target. One of the main use-cases is in combination with seccomp's user notification feature. As a reminder, seccomp's user notification feature was made available in v5.0. It allows a task to retrieve a file descriptor for its seccomp filter. The file descriptor is usually handed of to a more privileged supervising process. The supervisor can then listen for syscall events caught by the seccomp filter of the supervisee and perform actions in lieu of the supervisee, usually emulating syscalls. pidfd_getfd() is needed to expand its uses. There are currently two major users that wait on pidfd_getfd() and one future user: - Netflix, Sargun said, is working on a service mesh where users should be able to connect to a dns-based VIP. When a user connects to e.g. 1.2.3.4:80 that runs e.g. service "foo" they will be redirected to an envoy process. This service mesh uses seccomp user notifications and pidfd to intercept all connect calls and instead of connecting them to 1.2.3.4:80 connects them to e.g. 127.0.0.1:8080. - LXD uses the seccomp notifier heavily to intercept and emulate mknod() and mount() syscalls for unprivileged containers/processes. With pidfd_getfd() more uses-cases e.g. bridging socket connections will be possible. - The patchset has also seen some interest from the browser corner. Right now, Firefox is using a SECCOMP_RET_TRAP sandbox managed by a broker process. In the future glibc will start blocking all signals during dlopen() rendering this type of sandbox impossible. Hence, in the future Firefox will switch to a seccomp-user-nofication based sandbox which also makes use of file descriptor retrieval. The thread for this can be found at https://sourceware.org/ml/libc-alpha/2019-12/msg00079.html With pidfd_getfd() it is e.g. possible to bridge socket connections for the supervisee (binding to a privileged port) and taking actions on file descriptors on behalf of the supervisee in general. Sargun's first version was using an ioctl on pidfds but various people pushed for it to be a proper syscall which he duely implemented as well over various review cycles. Selftests are of course included. I've also added instructions how to deal with merge conflicts below. There's also a small fix coming from the kernel mentee project to correctly annotate struct sighand_struct with __rcu to fix various sparse warnings. We've received a few more such fixes and even though they are mostly trivial I've decided to postpone them until after -rc1 since they came in rather late and I don't want to risk introducing build warnings. Finally, there's a new prctl() command PR_{G,S}ET_IO_FLUSHER which is needed to avoid allocation recursions triggerable by storage drivers that have userspace parts that run in the IO path (e.g. dm-multipath, iscsi, etc). These allocation recursions deadlock the device. The new prctl() allows such privileged userspace components to avoid allocation recursions by setting the PF_MEMALLOC_NOIO and PF_LESS_THROTTLE flags. The patch carries the necessary acks from the relevant maintainers and is routed here as part of prctl() thread-management." * tag 'threads-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: prctl: PR_{G,S}ET_IO_FLUSHER to support controlling memory reclaim sched.h: Annotate sighand_struct with __rcu test: Add test for pidfd getfd arch: wire up pidfd_getfd syscall pid: Implement pidfd_getfd syscall vfs, fdtable: Add fget_task helper