sys/linux: update asset storage for new `syz_mount_image`

Asset storage is now significantly simpler: we just take the
Base64-encoded, compressed image and output it to a file. There is a
slight overhead in that we decompress from the `zlib` format and
re-compress to the `gzip` format.

This commit removes most of the logic from `init_images.go`,
and therefore most of the tests from `init_images_test.go`.
We could instead keep this logic around and use it to adapt old-style
`syz_mount_image` calls in existing corpuses to match the new format.

1 files changed, 11 insertions, 51 deletions

diff --git a/sys/linux/init_images_test.go b/sys/linux/init_images_test.go
index 1da41276e..c5b93c4be 100644
--- a/sys/linux/init_images_test.go
+++ b/sys/linux/init_images_test.go
@@ -7,14 +7,12 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"math/rand"
 	"os"
 	"path/filepath"
 	"reflect"
 	"sort"
 	"strings"
 	"testing"
-	"time"
 
 	"github.com/google/syzkaller/pkg/osutil"
 	"github.com/google/syzkaller/prog"
@@ -22,30 +20,24 @@ import (
 )
 
 // nolint: lll
+
 func TestSyzMountImageNeutralize(t *testing.T) {
 	prog.TestDeserializeHelper(t, targets.Linux, targets.AMD64, nil, []prog.DeserializeTest{
 		{
 			// A valid call, nothing should change.
-			In: `syz_mount_image$bfs(&(0x7f0000000000)='bfs\x00', &(0x7f0000000100)='./file0\x00', 0x2220, 0x2, &(0x7f0000000200)=[{&(0x7f0000010000)="cefaad1bc0210000ff0f0000ffffffffffffffffffffffffffffffff73797a6b616c73797a6b616c00"/64, 0x40, 0x0}, {&(0x7f0000010040)="0200000011000000140000001f22000002000000ed4100000000000001000000020000005ffb19635ffb19635ffb196300"/64, 0x40, 0x200}], 0x0, &(0x7f00000100a0)={[], [], 0x0}, 0x0)`,
+			In: `syz_mount_image$bfs(&(0x7f0000000000)='bfs\x00', &(0x7f0000000100)='./file0\x00', ` +
+				`0xdeadbeef, 0x15, 0x0, &(0x7f00000100a0)={[], [], 0x0}, 0x0, ` +
+				`&(0x7f0000000200)="$eJwqrqzKTszJSS0CBAAA//8TyQPi")`,
 		},
 		{
-			// Invalid total size.
-			In: `syz_mount_image$bfs(&(0x7f0000000000)='bfs\x00', &(0x7f0000000100)='./file1\x00', 0x20, 0x2, &(0x7f0000000200)=[{&(0x7f0000010000)="cefaad1bc0210000ff0f0000ffffffffffffffffffffffffffffffff73797a6b616c73797a6b616c00"/64, 0x40, 0x0}, {&(0x7f0000010040)="0200000011000000140000001f22000002000000ed4100000000000001000000020000005ffb19635ffb19635ffb196300"/64, 0x40, 0x200}], 0x0, &(0x7f00000100a0)={[], [], 0x0}, 0x0)`,
+			// Invalid compressed size.
+			In: `syz_mount_image$bfs(&(0x7f0000000000)='bfs\x00', &(0x7f0000000100)='./file0\x00', ` +
+				`0xdeadbeef, 0xdeadbeef, 0x0, &(0x7f00000100a0)={[], [], 0x0}, 0x0, ` +
+				`&(0x7f0000000200)="$eJwqrqzKTszJSS0CBAAA//8TyQPi")`,
 			// It should be able to fix up the size.
-			Out: `syz_mount_image$bfs(&(0x7f0000000000)='bfs\x00', &(0x7f0000000100)='./file1\x00', 0x240, 0x2, &(0x7f0000000200)=[{&(0x7f0000010000)="cefaad1bc0210000ff0f0000ffffffffffffffffffffffffffffffff73797a6b616c73797a6b616c00"/64, 0x40, 0x0}, {&(0x7f0000010040)="0200000011000000140000001f22000002000000ed4100000000000001000000020000005ffb19635ffb19635ffb196300"/64, 0x40, 0x200}], 0x0, &(0x7f00000100a0)={[], [], 0x0}, 0x0)`,
-		},
-		{
-			// Invalid offset.
-			In: `syz_mount_image$bfs(&(0x7f0000000000)='bfs\x00', &(0x7f0000000100)='./file1\x00', 0x20, 0x2, &(0x7f0000000200)=[{&(0x7f0000010000)="cefaad1bc0210000ff0f0000ffffffffffffffffffffffffffffffff73797a6b616c73797a6b616c00"/64, 0x40, 0x0}, {&(0x7f0000010040)="0200000011000000140000001f22000002000000ed4100000000000001000000020000005ffb19635ffb19635ffb196300"/64, 0x40, 0x9100000}], 0x0, &(0x7f00000100a0)={[], [], 0x0}, 0x0)`,
-			// The segment is deleted.
-			Out:       `syz_mount_image$bfs(&(0x7f0000000000)='bfs\x00', &(0x7f0000000100)='./file1\x00', 0x40, 0x1, &(0x7f0000000200)=[{&(0x7f0000010000)="cefaad1bc0210000ff0f0000ffffffffffffffffffffffffffffffff73797a6b616c73797a6b616c00"/64, 0x40, 0x0}], 0x0, &(0x7f00000100a0)={[], [], 0x0}, 0x0)`,
-			StrictErr: `got filtered out`,
-		},
-		{
-			// Overlapping and unsorted segments.
-			In:        `syz_mount_image$bfs(&(0x7f0000000000)='bfs\x00', &(0x7f0000000100)='./file0\x00', 0x2220, 0x3, &(0x7f0000000200)=[{&(0x7f0000010000)="cafef00d"/64, 0x50, 0x20}, {&(0x7f0000010040)="deadbeef"/64, 0x30, 0x10}, {&(0x7f0000010080)="abcdef"/64, 0x40, 0x20}], 0x0, &(0x7f00000100a0)={[], [], 0x0}, 0x0)`,
-			Out:       `syz_mount_image$bfs(&(0x7f0000000000)='bfs\x00', &(0x7f0000000100)='./file0\x00', 0x2220, 0x2, &(0x7f0000000200)=[{&(0x7f0000010040)="deadbeef00"/16, 0x10, 0x10}, {&(0x7f0000010000)="cafef00d00"/64, 0x40, 0x20}], 0x0, &(0x7f00000100a0)={[], [], 0x0}, 0x0)`,
-			StrictErr: `segments are not sorted`,
+			Out: `syz_mount_image$bfs(&(0x7f0000000000)='bfs\x00', &(0x7f0000000100)='./file0\x00', ` +
+				`0xdeadbeef, 0x15, 0x0, &(0x7f00000100a0)={[], [], 0x0}, 0x0, ` +
+				`&(0x7f0000000200)="$eJwqrqzKTszJSS0CBAAA//8TyQPi")`,
 		},
 	})
 }
@@ -120,35 +112,3 @@ func TestExtractSyzMountImage(t *testing.T) {
 		t.Fatalf("all out files: %v\ntested files: %v", allOutFiles, testedOutFiles)
 	}
 }
-
-// nolint: lll
-func TestSyzMountImageMutation(t *testing.T) {
-	// We cannot unfortunately just import InitTest from prog.
-	rs := rand.NewSource(time.Now().UnixNano())
-	iters := 100
-	target, err := prog.GetTarget("linux", "amd64")
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	var p *prog.Prog
-	var ct *prog.ChoiceTable
-
-	const mutateCount = 1000
-	const baseProg = `syz_mount_image$bfs(&(0x7f0000000000)='bfs\x00', &(0x7f0000000100)='./file0\x00', 0x2220, 0x2, &(0x7f0000000200)=[{&(0x7f0000010040)="deadbeef00"/16, 0x10, 0x10}, {&(0x7f0000010000)="cafef00d00"/64, 0x40, 0x20}], 0x0, &(0x7f00000100a0)={[], [], 0x0}, 0x0)`
-
-	for i := 0; i < iters; i++ {
-		if i%mutateCount == 0 {
-			var err error
-			p, err = target.Deserialize([]byte(baseProg), prog.NonStrict)
-			if err != nil {
-				t.Fatal(err)
-			}
-			ct = target.DefaultChoiceTable()
-		}
-		p.Mutate(rs, 1, ct, nil, nil)
-		// We only call the extraction code and do mutations to catch possible panics.
-		// It is absolutely normal for syzkaller to mutate the call to the level when the image can no longer be extracted.
-		p.Target.ExtractMountedImage(p.Calls[0])
-	}
-}