Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

cmd/internal/obj/wasm: avoid invalid offsets for Load/Store

Browse source 
Offsets for Load and Store instructions have type i32. Bad index
expression offsets can cause an offset to be larger than MaxUint32,
which is not allowed. One example for this is the test test/index0.go.

Generate valid code by adding a guard to the responsible rewrite rule.
Also emit a proper error when using such a bad index in assembly code.

Change-Id: Ie90adcbf3ae3861c26680eb81790f28692913ccf
Reviewed-on: https://go-review.googlesource.com/111955
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit is contained in:
Richard Musiol 2018-05-07 16:18:19 +02:00 • committed by Cherry Zhang
parent 10529a01fd
commit bf23a4e61d
3 changed files with 34 additions and 33 deletions
Download patch file Download diff file Expand all files Collapse all files

6
src/cmd/internal/obj/wasm/wasmobj.go
View file

@ -870,6 +870,9 @@ func assemble(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
if p.From.Type != obj.TYPE_CONST {
panic("bad type for *Load")
}
if p.From.Offset > math.MaxUint32 {
ctxt.Diag("bad offset in %v", p)
}
writeUleb128(w, align(p.As))
writeUleb128(w, uint64(p.From.Offset))
@ -877,6 +880,9 @@ func assemble(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
if p.To.Offset < 0 {
panic("negative offset")
}
if p.From.Offset > math.MaxUint32 {
ctxt.Diag("bad offset in %v", p)
}
writeUleb128(w, align(p.As))
writeUleb128(w, uint64(p.To.Offset))