encoding/gob: use saferio.SliceCap when decoding a slice

This avoids allocating an overly large slice for corrupt input.

Change the saferio.SliceCap function to take a pointer to the element type,
so that we can handle slices of interface types. This revealed that a
couple of existing calls were actually incorrect, passing the slice type
rather than the element type.

No test case because the problem can only happen for invalid data. Let
the fuzzer find cases like this.

Fixes #55338

Change-Id: I3c1724183cc275d4981379773b0b8faa01a9cbd2
Reviewed-on: https://go-review.googlesource.com/c/go/+/433296
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/debug/pe/symbol.go b/src/debug/pe/symbol.go
index 0a5343f925..b1654f8726 100644
--- a/src/debug/pe/symbol.go
+++ b/src/debug/pe/symbol.go
@@ -59,7 +59,7 @@ func readCOFFSymbols(fh *FileHeader, r io.ReadSeeker) ([]COFFSymbol, error) {
 	if err != nil {
 		return nil, fmt.Errorf("fail to seek to symbol table: %v", err)
 	}
-	c := saferio.SliceCap(COFFSymbol{}, uint64(fh.NumberOfSymbols))
+	c := saferio.SliceCap((*COFFSymbol)(nil), uint64(fh.NumberOfSymbols))
 	if c < 0 {
 		return nil, errors.New("too many symbols; file may be corrupt")
 	}