tree 7a1091cde70530c889b72ad8bd471de1fcc0853f
parent 2043b3b47b3ca76d8ce44f05a77e48d2291b6fc6
author Cherry Mui <cherryyz@google.com> 1630615919 -0400
committer Michael Knyszek <mknyszek@google.com> 1633632353 +0000

misc/wasm, cmd/link: do not let command line args overwrite global data

On Wasm, wasm_exec.js puts command line arguments at the beginning
of the linear memory (following the "zero page"). Currently there
is no limit for this, and a very long command line can overwrite
the program's data section. Prevent this by limiting the command
line to 4096 bytes, and in the linker ensuring the data section
starts at a high enough address (8192).

(Arguably our address assignment on Wasm is a bit confusing. This
is the minimum fix I can come up with.)

Thanks to Ben Lubar for reporting this issue.

Fixes #48797
Fixes CVE-2021-38297

Change-Id: I0f50fbb2a5b6d0d047e3c134a88988d9133e4ab3
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1205933
Reviewed-by: Roland Shoemaker <bracewell@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/354571
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>