cmd/go: enforce flags with non-optional arguments
Enforce that linker flags which expect arguments get them, otherwise it
may be possible to smuggle unexpected flags through as the linker can
consume what looks like a flag as an argument to a preceding flag (i.e.
"-Wl,-O -Wl,-R,-bad-flag" is interpreted as "-O=-R -bad-flag"). Also be
somewhat more restrictive in the general format of some flags.
Thanks to Juho Nurminen of Mattermost for reporting this issue.
Fixes #60305
Fixes CVE-2023-29404
Change-Id: I913df78a692cee390deefc3cd7d8f5b031524fc9
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/
1876275
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/501225
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>