Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

x/net/icmp: PacketConn.ReadFrom on an unprivileged PacketConn on darwin returns the entire IP packet #47369

Open
magisterquis opened this issue Jul 24, 2021 · 0 comments
Open

x/net/icmp: PacketConn.ReadFrom on an unprivileged PacketConn on darwin returns the entire IP packet #47369

magisterquis opened this issue Jul 24, 2021 · 0 comments
Labels
NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one.
Milestone
Unreleased

Comments

@magisterquis
Copy link

What version of Go are you using (go version)?

$ go version
go version go1.16.6 openbsd/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output
$ go env
GO111MODULE="auto"
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/stuart/.cache/go-build"
GOENV="/home/stuart/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="openbsd"
GOINSECURE=""
GOMODCACHE="/home/stuart/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="openbsd"
GOPATH="/home/stuart/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/stuart/.goroot"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/stuart/.goroot/pkg/tool/openbsd_amd64"
GOVCS=""
GOVERSION="go1.16.6"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="0"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build1897681582=/tmp/go-build -gno-record-gcc-switches"

What did you do?

https://play.golang.org/p/oNQqxusHBf1

The program sends a ping first with a privileged socket and then with an unprivileged socket.

What did you expect to see?

I expect to see the returned ICMP payloads to be fairly similar. On Linux, they are.
Linux:

2021/07/24 10:43:11 [udp4] Read 8 bytes: 0000ba9700274541
2021/07/24 10:43:11 [ip4:icmp] Read 8 bytes: 000000d37f967f96

What did you see instead?

The read from the unprivileged socket on Darwin included the IP header before the ICMP header.
Darwin:

2021/07/24 12:43:43 [udp4] Read 28 bytes: 45600800000000007001269d080808080a0209d30000fcff01800180
2021/07/24 12:43:43 [ip4:icmp] Read 8 bytes: 0000c75e9c509c50

This seems due to the check in https://cs.opensource.google/go/x/net/+/853a4619:icmp/endpoint.go;l=54 which (apparently) doesn't apply to unprivileged sockets.
@gopherbot gopherbot added this to the Unreleased milestone Jul 24, 2021
@seankhliao seankhliao added the NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. label Jul 25, 2021
touchardv added a commit to touchardv/myhome-presence that referenced this issue Oct 3, 2021
@touchardv
Fix issue with icmp received bytes.
42ec38f 
It seems the packet is bigger than expected? Seems to be as golang/go#47369
"x/net/icmp: PacketConn.ReadFrom on an unprivileged PacketConn on darwin returns the entire IP packet #47369"
@floatingstatic floatingstatic mentioned this issue May 19, 2023
Merged
@myriadtim myriadtim mentioned this issue Jun 7, 2023
Open
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one.
Projects
None yet
Milestone
Unreleased
Development

No branches or pull requests
3 participants
@magisterquis @gopherbot @seankhliao