pkg/subsystem: add the basic caller-facing interface

Users of the pkg/subsystem are only interested in
1) Fetching the list of subsystems for a given OS.
2) Matching a crash against the extracted set of subsystems.

1 files changed, 69 insertions, 0 deletions

diff --git a/pkg/subsystem/raw_extractor_test.go b/pkg/subsystem/raw_extractor_test.go
new file mode 100644
index 000000000..9d221af86
--- /dev/null
+++ b/pkg/subsystem/raw_extractor_test.go
@@ -0,0 +1,69 @@
+// Copyright 2023 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package subsystem
+
+import (
+	"testing"
+
+	"github.com/google/syzkaller/pkg/subsystem/entity"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSubsystemExtractor(t *testing.T) {
+	ioUring := &entity.Subsystem{
+		Name: "io_uring",
+		PathRules: []entity.PathRule{
+			{
+				IncludeRegexp: `io_uring/.*`,
+			},
+		},
+		Syscalls: []string{"syz_io_uring_setup"},
+	}
+	security := &entity.Subsystem{
+		Name: "security",
+		PathRules: []entity.PathRule{
+			{
+				IncludeRegexp: `security/.*`,
+				ExcludeRegexp: `security/selinux/.*`,
+			},
+			{
+				IncludeRegexp: `net/ipv6/calipso\.c`,
+			},
+		},
+	}
+	net := &entity.Subsystem{
+		Name: "net",
+		PathRules: []entity.PathRule{
+			{
+				IncludeRegexp: `net/.*`,
+			},
+		},
+	}
+	obj := makeRawExtractor([]*entity.Subsystem{ioUring, security, net})
+
+	// Verify path matching.
+	assert.ElementsMatch(t, obj.FromPath(`io_uring/file.c`), []*entity.Subsystem{ioUring})
+	assert.ElementsMatch(t, obj.FromPath(`security/file.c`), []*entity.Subsystem{security})
+	assert.ElementsMatch(t, obj.FromPath(`security/selinux/file.c`), []*entity.Subsystem{})
+	assert.ElementsMatch(t, obj.FromPath(`net/ipv6/calipso.c`), []*entity.Subsystem{net, security})
+
+	// Verify prog matching.
+	// nolint: lll
+	assert.ElementsMatch(t, obj.FromProg([]byte(
+		`# https://syzkaller.appspot.com/bug?id=708185e841adf6ca28fc50b126fdf9825fd8ae43
+# See https://goo.gl/kgGztJ for information about syzkaller reproducers.
+#{"repeat":true,"procs":1,"slowdown":1,"sandbox":"","close_fds":false}
+r0 = syz_io_uring_setup(0x3ee4, &(0x7f0000000240), &(0x7f0000002000/0x2000)=nil, &(0x7f0000ffd000/0x3000)=nil, &(0x7f0000000100)=<r1=>0x0, &(0x7f0000000140)=<r2=>0x0)
+socket$inet_udplite(0x2, 0x2, 0x88)
+r3 = openat$ptmx(0xffffffffffffff9c, &(0x7f0000000040), 0x8a04, 0x0)
+syz_io_uring_submit(r1, r2, &(0x7f0000000000)=@IORING_OP_READ=@pass_buffer={0x16, 0x0, 0x0, @fd_index=0x5, 0x0, 0x0}, 0x0)
+ioctl$TIOCSETD(r3, 0x5423, &(0x7f0000000580)=0x3)
+io_uring_enter(r0, 0x2ff, 0x0, 0x0, 0x0, 0x0)`)),
+		[]*entity.Subsystem{ioUring})
+	// nolint: lll
+	assert.ElementsMatch(t, obj.FromProg([]byte(
+		`syz_mount_image$nilfs2(&(0x7f0000000000), &(0x7f0000000100)='./file0\x00', 0x100000, 0x3b, &(0x7f0000000200)=[{&(0x7f0000011240)="02", 0x1}, {&(0x7f0000012a40)="03000000", 0x4, 0x1}], 0x0, &(0x7f00000131c0), 0x1)
+openat$incfs(0xffffffffffffff9c, &(0x7f0000000000)='.pending_reads\x00', 0x4040, 0x0)`)),
+		[]*entity.Subsystem{})
+}