Since commit afcc90f8621e ("usercopy: WARN() on slab cache usercopy
region violations"), MIPS systems booting with a compat root filesystem
emit a warning when copying compat siginfo to userspace:
WARNING: CPU: 0 PID: 953 at mm/usercopy.c:81 usercopy_warn+0x98/0xe8
Bad or missing usercopy whitelist? Kernel memory exposure attempt
detected from SLAB object 'task_struct' (offset 1432, size 16)!
Modules linked in:
CPU: 0 PID: 953 Comm: S01logging Not tainted 4.16.0-rc2 #10
Stack : ffffffff808c0000 0000000000000000 0000000000000001 65ac85163f3bdc4a
65ac85163f3bdc4a 0000000000000000 90000000ff667ab8 ffffffff808c0000
00000000000003f8 ffffffff808d0000 00000000000000d1 0000000000000000
000000000000003c 0000000000000000 ffffffff808c8ca8 ffffffff808d0000
ffffffff808d0000 ffffffff80810000 fffffc0000000000 ffffffff80785c30
0000000000000009 0000000000000051 90000000ff667eb0 90000000ff667db0
000000007fe0d938 0000000000000018 ffffffff80449958 0000000020052798
ffffffff808c0000 90000000ff664000 90000000ff667ab0 00000000100c0000
ffffffff80698810 0000000000000000 0000000000000000 0000000000000000
0000000000000000 0000000000000000 ffffffff8010d02c 65ac85163f3bdc4a
...
Call Trace:
[<ffffffff8010d02c>] show_stack+0x9c/0x130
[<ffffffff80698810>] dump_stack+0x90/0xd0
[<ffffffff80137b78>] __warn+0x100/0x118
[<ffffffff80137bdc>] warn_slowpath_fmt+0x4c/0x70
[<ffffffff8021e4a8>] usercopy_warn+0x98/0xe8
[<ffffffff8021e68c>] __check_object_size+0xfc/0x250
[<ffffffff801bbfb8>] put_compat_sigset+0x30/0x88
[<ffffffff8011af24>] setup_rt_frame_n32+0xc4/0x160
[<ffffffff8010b8b4>] do_signal+0x19c/0x230
[<ffffffff8010c408>] do_notify_resume+0x60/0x78
[<ffffffff80106f50>] work_notifysig+0x10/0x18
---[ end trace 88fffbf69147f48a ]---
Commit 5905429ad856 ("fork: Provide usercopy whitelisting for
task_struct") noted that:
"While the blocked and saved_sigmask fields of task_struct are copied to
userspace (via sigmask_to_save() and setup_rt_frame()), it is always
copied with a static length (i.e. sizeof(sigset_t))."
However, this is not true in the case of compat signals, whose sigset
is copied by put_compat_sigset and receives size as an argument.
At most call sites, put_compat_sigset is copying a sigset from the
current task_struct. This triggers a warning when
CONFIG_HARDENED_USERCOPY is active. However, by marking this function as
static inline, the warning can be avoided because in all of these cases
the size is constant at compile time, which is allowed. The only site
where this is not the case is handling the rt_sigpending syscall, but
there the copy is being made from a stack local variable so does not
trigger the warning.
Move put_compat_sigset to compat.h, and mark it static inline. This
fixes the WARN on MIPS.
Fixes: afcc90f8621e ("usercopy: WARN() on slab cache usercopy region violations")
Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: "Dmitry V . Levin" <ldv@altlinux.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: kernel-hardening@lists.openwall.com
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18639/
Signed-off-by: James Hogan <jhogan@kernel.org>
CPUmasks are never big enough to warrant 64-bit code. Space savings: add/remove: 0/0 grow/shrink: 1/4 up/down: 3/-17 (-14) Function old new delta sched_init_numa 1530 1533 +3 compat_sys_sched_setaffinity 160 159 -1 sys_sched_getaffinity 197 195 -2 sys_sched_setaffinity 183 176 -7 compat_sys_sched_getaffinity 179 172 -7 Link: http://lkml.kernel.org/r/20171204165531.GA8221@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
switch to using timespec64 internally, while we are at it Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
similar to put_compat_sigset() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
no users left Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There are 4 callers of sigset_to_compat() in the entire kernel. One is in sparc compat rt_sigaction(2), the rest are in kernel/signal.c itself. All are followed by copy_to_user(), and all but the sparc one are under "if it's big-endian..." ifdefs. Let's transform sigset_to_compat() into put_compat_sigset() that also calls copy_to_user(). Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... and finally kill the sodding compat_convert_timespec() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull misc compat stuff updates from Al Viro:
"This part is basically untangling various compat stuff. Compat
syscalls moved to their native counterparts, getting rid of quite a
bit of double-copying and/or set_fs() uses. A lot of field-by-field
copyin/copyout killed off.
- kernel/compat.c is much closer to containing just the
copyin/copyout of compat structs. Not all compat syscalls are gone
from it yet, but it's getting there.
- ipc/compat_mq.c killed off completely.
- block/compat_ioctl.c cleaned up; floppy compat ioctls moved to
drivers/block/floppy.c where they belong. Yes, there are several
drivers that implement some of the same ioctls. Some are m68k and
one is 32bit-only pmac. drivers/block/floppy.c is the only one in
that bunch that can be built on biarch"
* 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
mqueue: move compat syscalls to native ones
usbdevfs: get rid of field-by-field copyin
compat_hdio_ioctl: get rid of set_fs()
take floppy compat ioctls to sodding floppy.c
ipmi: get rid of field-by-field __get_user()
ipmi: get COMPAT_IPMICTL_RECEIVE_MSG in sync with the native one
rt_sigtimedwait(): move compat to native
select: switch compat_{get,put}_fd_set() to compat_{get,put}_bitmap()
put_compat_rusage(): switch to copy_to_user()
sigpending(): move compat to native
getrlimit()/setrlimit(): move compat to native
times(2): move compat to native
compat_{get,put}_bitmap(): use unsafe_{get,put}_user()
fb_get_fscreeninfo(): don't bother with do_fb_ioctl()
do_sigaltstack(): lift copying to/from userland into callers
take compat_sys_old_getrlimit() to native syscall
trim __ARCH_WANT_SYS_OLD_GETRLIMIT
Pull timer-related user access updates from Al Viro:
"Continuation of timers-related stuff (there had been more, but my
parts of that series are already merged via timers/core). This is more
of y2038 work by Deepa Dinamani, partially disrupted by the
unification of native and compat timers-related syscalls"
* 'timers-compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
posix_clocks: Use get_itimerspec64() and put_itimerspec64()
timerfd: Use get_itimerspec64() and put_itimerspec64()
nanosleep: Use get_timespec64() and put_timespec64()
posix-timers: Use get_timespec64() and put_timespec64()
posix-stubs: Conditionally include COMPAT_SYS_NI defines
time: introduce {get,put}_itimerspec64
time: add get_timespec64 and put_timespec64
Pull wait syscall updates from Al Viro: "Consolidating sys_wait* and compat counterparts. Gets rid of set_fs()/double-copy mess, simplifies the whole thing (lifting the copyouts to the syscalls means less headache in the part that does actual work - fewer failure exits, to start with), gets rid of the overhead of field-by-field __put_user()" * 'work.sys_wait' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: osf_wait4: switch to kernel_wait4() waitid(): switch copyout of siginfo to unsafe_put_user() wait_task_zombie: consolidate info logics kill wait_noreap_copyout() lift getrusage() from wait_noreap_copyout() waitid(2): leave copyout of siginfo to syscall itself kernel_wait4()/kernel_waitid(): delay copying status to userland wait4(2)/waitid(2): separate copying rusage to userland move compat wait4 and waitid next to native variants