tools/syz-trace2syz/proggen: fix vma allocation

There are 2 bugs:
1. We always allocate 1 page, even if use more.
2. VMA addresses are not aligned, so most mmap-like functions fail with EINVAL.
The added test currently panics with "unaligned vma address".

3 files changed, 17 insertions, 1 deletions

diff --git a/prog/target.go b/prog/target.go
index f99c45c5b..56fbb860d 100644
--- a/prog/target.go
+++ b/prog/target.go
@@ -264,6 +264,12 @@ func (pg *ProgGen) Allocate(size uint64) uint64 {
 	return pg.ma.alloc(nil, size)
 }
 
+func (pg *ProgGen) AllocateVMA(npages uint64) uint64 {
+	psize := pg.target.PageSize
+	addr := pg.ma.alloc(nil, (npages+1)*psize)
+	return (addr + psize - 1) & ^(psize - 1)
+}
+
 func (pg *ProgGen) Finalize() (*Prog, error) {
 	if err := pg.p.validate(); err != nil {
 		return nil, err
diff --git a/tools/syz-trace2syz/proggen/proggen.go b/tools/syz-trace2syz/proggen/proggen.go
index 967167fe9..a1394d057 100644
--- a/tools/syz-trace2syz/proggen/proggen.go
+++ b/tools/syz-trace2syz/proggen/proggen.go
@@ -167,7 +167,7 @@ func genVma(syzType *prog.VmaType, _ parser.IrType, ctx *Context) prog.Arg {
 	if syzType.RangeBegin != 0 || syzType.RangeEnd != 0 {
 		npages = syzType.RangeEnd
 	}
-	return prog.MakeVmaPointerArg(syzType, ctx.pg.Allocate(ctx.Target.PageSize), npages)
+	return prog.MakeVmaPointerArg(syzType, ctx.pg.AllocateVMA(npages), npages)
 }
 
 func genArray(syzType *prog.ArrayType, traceType parser.IrType, ctx *Context) prog.Arg {
diff --git a/tools/syz-trace2syz/proggen/proggen_test.go b/tools/syz-trace2syz/proggen/proggen_test.go
index 1e7a5f3a6..8f56de2d5 100644
--- a/tools/syz-trace2syz/proggen/proggen_test.go
+++ b/tools/syz-trace2syz/proggen/proggen_test.go
@@ -62,6 +62,16 @@ func TestParseTraceBasic(t *testing.T) {
 	}
 }
 
+func TestParseVMA(t *testing.T) {
+	test := `pipe({0x0, 0x1}) = 0
+		 shmget(0x0, 0x1, 0x2, 0x3) = 0`
+	p := parseSingleTrace(t, test)
+	expectedSeq := "pipe-shmget"
+	if p.String() != expectedSeq {
+		t.Fatalf("expected: %s != %s", expectedSeq, p.String())
+	}
+}
+
 func TestParseTraceInnerResource(t *testing.T) {
 	test := `pipe([5,6]) = 0
 			 write(6, "\xff\xff\xfe\xff", 4) = 4`