stable inclusion
from stable-v5.10.133
commit 7723edf5edfdfdabd8234e45142be86598a04cad
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5PTAS
CVE: CVE-2022-29900,CVE-2022-23816,CVE-2022-29901

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7723edf5edfdfdabd8234e45142be86598a04cad

--------------------------------

commit ee88d363 upstream.

In addition to teaching static_call about the new way to spell 'RET',
there is an added complication in that static_call() is allowed to
rewrite text before it is known which particular spelling is required.

In order to deal with this; have a static_call specific fixup in the
apply_return() 'alternative' patching routine that will rewrite the
static_call trampoline to match the definite sequence.

This in turn creates the problem of uniquely identifying static call
trampolines. Currently trampolines are 8 bytes, the first 5 being the
jmp.d32/ret sequence and the final 3 a byte sequence that spells out
'SCT'.

This sequence is used in __static_call_validate() to ensure it is
patching a trampoline and not a random other jmp.d32. That is,
false-positives shouldn't be plenty, but aren't a big concern.

OTOH the new __static_call_fixup() must not have false-positives, and
'SCT' decodes to the somewhat weird but semi plausible sequence:

  push %rbx
  rex.XB push %r12

Additionally, there are SLS concerns with immediate jumps. Combined it
seems like a good moment to change the signature to a single 3 byte
trap instruction that is unique to this usage and will not ever get
generated by accident.

As such, change the signature to: '0x0f, 0xb9, 0xcc', which decodes
to:

  ud1 %esp, %ecx
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: NBorislav Petkov <bp@suse.de>
[cascardo: skip validation as introduced by 2105a927 ("static_call,x86: Robustify trampoline patching")]
Signed-off-by: NThadeu Lima de Souza Cascardo <cascardo@canonical.com>
[bwh: Backported to 5.10: adjust context]
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

conflict:
	arch/x86/kernel/static_call.c
Signed-off-by: NLin Yujun <linyujun809@huawei.com>
Reviewed-by: NZhang Jianhua <chris.zjh@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>