linux - tools/objtool/tests/x86/test-kcfi.sh

39 lines · 1.1 KiB

1	#!/bin/bash
2	# SPDX-License-Identifier: GPL-2.0
3	#
4	# Under kCFI an indirect call checks a type hash before jumping, and traps on a
5	# mismatch. Two things belong to the calling function and must come with it
6	# into a patch:
7	#
8	# - the __cfi_<func> prefix symbol holding the hash. Lose it and the patched
9	# function has no type identity, so indirect calls to it trap.
10	# - its .kcfi_traps entry. Lose that and the trap is not recognised as a
11	# CFI failure, so what should be a clean report becomes an oops.
12	#
13	# Neither shows up at build time.
14
15	. "$(dirname "$0")/../lib.sh"
16
17	clang_only "kCFI is a Clang feature"
18
19	setup
20
21	# Declared above that this is Clang's; a given Clang may still be too old.
22	cc_supports -fsanitize=kcfi \|\|
23	probe_skip "this clang does not support -fsanitize=kcfi"
24
25	build_pair kcfi.c -fsanitize=kcfi
26
27	assert_input_section .kcfi_traps
28	assert_input_symbol __cfi_target
29
30	run_diff
31
32	assert_patched target
33
34	# The prefix symbol comes with its function ...
35	assert_symbol __cfi_target
36	# ... and so does the trap entry.
37	assert_section .kcfi_traps
38
39	pass "kCFI prefix symbol and trap entry carried with the patched function"