macOS crash unknown sockaddr

[ChristopherHX]

I would suggest skip copying unknown socket types to bionic and avoid a crash,
or better log them in debug mode.
cannot test myself, reported issues.

libc-shim/src/network.cpp

Line 310 in cdeba56

*res = bionic::from_host_alloc(hres);

libc-shim/src/file_misc.cpp

Line 59 in cdeba56

bionic::from_host(&hbuf.ifc_req[i].ifr_addr, &buf->req->addr);

[MCMrARM]

probably should only crash on shim errors in debug mode, and for release only log them

[MCMrARM]

there's a good chance the second one got fixed though

[ChristopherHX]

second one still crash with current libc-shim, unknown macOS version
minecraft-linux/mcpelauncher-manifest#341 (comment)
But now more somehow get a crash, most of them don't post a log.

[andy-mortimer]

Moving over from the referenced issue. I'm on 10.15.5. I've checked NG version 0.0.168 from https://github.com/ChristopherHX/osx-packaging-scripts/releases/tag/ng.dmg and confirmed that it does work, where the newer 0.0.175 does not. The last parts of the log probably don't help, but just in case it's useful:

linker: dlsym(handle=0x0("n/a"), sym_name="glPopGroupMarkerEXT", sym_ver="(null)", caller="/Users/andy-user/Library/Application Support/mcpelauncher/versions/1.16.0.2/lib/x86_64/libminecraftpe.so", caller_ns=@0x1081277f0) ...
linker: dlsym failed: invalid handle: 0x0
linker: ... dlsym failed: dlsym failed: invalid handle: 0x0
21:01:12 Warn  [Minecraft] NO LOG FILE! - [Device Lost] The graphics context was gained
21:01:12 Warn  [Minecraft] MinecraftGame::init && MinecraftGame::setSize!
21:01:13 Debug [XSAPI.Android] sign_in_impl: will NOT be showing UI
21:01:13 Info  [XboxInterop] InvokeMSA: requestCode=1 cid=6cf42dea7aadd41d
21:01:13 Trace [DaemonLauncher] Starting daemon: /Applications/Minecraft Bedrock Launcher.app/Contents/MacOS/./msa-daemon
21:01:18 Info  [Minecraft] NO LOG FILE! - IPv4 supported, port: 56662
21:01:18 Info  [Minecraft] NO LOG FILE! - IPv6 supported, port: 56663
21:01:18 Info  [Minecraft] NO LOG FILE! - IPv4 supported, port: 57562
21:01:18 Info  [Minecraft] NO LOG FILE! - IPv6 supported, port: 57563

... and then successfully shows the main menu. Logs from 0.0.175 at minecraft-linux/mcpelauncher-manifest#341 (comment) .

Let me know if there's anything else I can do to help test / narrow down the issue. I have XCode and am an experienced Windows developer but I'm fairly new to MacOS and its tools and libraries.

[ChristopherHX]

It would help if you could debug this line with gdb

libc-shim/src/network.cpp

Line 106 in f07b952

default: throw std::runtime_error("Unknown socket family when converting sockaddr from host");

Then provide us the value of in->sa_family.

src https://github.com/minecraft-linux/mcpelauncher-manifest/tree/ng

git clone https://github.com/minecraft-linux/mcpelauncher-manifest --recursive -b ng
mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Debug
make -j8 mcpelauncher-client

You could run it from a terminal

mcpelauncher-client/mcpelauncher-client -dg ~/Library/Application\ Support/mcpelauncher/versions/1.16.1.02

Debugging are more steps
I'm like you more a windows developer

[andy-mortimer]

It seems to be AF_LINK. I couldn't get gdb to work (got lost trying to get it codesigned) but printing the value to cerr gives 18, which is defined as AF_LINK in
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/sys/socket.h, and adding a case for AF_LINK does trigger:

diff --git a/src/network.cpp b/src/network.cpp
index e00207f..0ea906c 100644
--- a/src/network.cpp
+++ b/src/network.cpp
@@ -103,7 +103,11 @@ void bionic::from_host(const ::sockaddr *in, bionic::sockaddr *out) {
             memcpy(((bionic::sockaddr_in6 *) out)->addr, ((::sockaddr_in6*) in)->sin6_addr.s6_addr, 16);
             ((bionic::sockaddr_in6 *) out)->scope = ((::sockaddr_in6*) in)->sin6_scope_id;
             break;
-        default: throw std::runtime_error("Unknown socket family when converting sockaddr from host");
+       case AF_LINK:
+           throw std::runtime_error("AF_LINK socket family when converting sockaddr from host");
+        default: 
+           //std::cerr << "af_family " << (int)in->sa_family << std::endl;
+           throw std::runtime_error("Unknown socket family when converting sockaddr from host");
     }
 }
 

[andy-mortimer]

This crash appears to be triggered by 01d8ebb . If I go back to ab54671, it goes away.

Looking at the commit and doing a little googling, it looks like this is indeed fixing things compared to the original implementation, so presumably this is one of those problem-hides-another-problem cases and reverting this commit probably isn't the fix! I will see if I can find any more, but I'm a bit in the dark as to what this code is all about ... any clues welcome

[MCMrARM]

Proper fix is to add AF_LINK to the translation layer, no?

[andy-mortimer]

Yes, I think so. I will try it when I get a chance. I'm still learning my way around, so the little time I have for this doesn't progress me very fast!

[andy-mortimer]

It wasn't that easy! PR #4 updated to ignore them, let me know what you think.

[ChristopherHX]

I think found a problem, the loop is wrong for macOS
https://gist.github.com/OrangeTide/909204#file-showif-c-L60
sizeof ifreq is not the way to go on macOS

[MCMrARM]

Seems the correct way to do it is using _SIZEOF_ADDR_IFREQ if available. See: https://opensource.apple.com/source/postfix/postfix-174/postfix/src/util/inet_addr_local.c.auto.html for an example

#if defined(_SIZEOF_ADDR_IFREQ)
#define NEXT_INTERFACE(ifr)	((struct ifreq *) \
	((char *) ifr + _SIZEOF_ADDR_IFREQ(*ifr)))
#define IFREQ_SIZE(ifr)	_SIZEOF_ADDR_IFREQ(*ifr)
#elif defined(HAS_SA_LEN)
#define NEXT_INTERFACE(ifr)	((struct ifreq *) \
	((char *) ifr + sizeof(ifr->ifr_name) + ifr->ifr_addr.sa_len))
#define IFREQ_SIZE(ifr)	(sizeof(ifr->ifr_name) + ifr->ifr_addr.sa_len)
#else
#define NEXT_INTERFACE(ifr)	(ifr + 1)
#define IFREQ_SIZE(ifr)	sizeof(ifr[0])
#endif

That's unexpected to be honest thanks for investigating it @ChristopherHX .

[ChristopherHX]

Calling this method manually make it reproduceable for me, will add tests to this launcher soon.

My dump of inet families of the ioctl
AF_LINK=18
AF_INET6=30
AF_INET=2
Should be fixed soon in ng, ignoring AF_LINK to match linux

ifr_name: 'lo0'
sa_family: 18
ifr_name: 'lo0'
sa_family: 2
ifr_name: 'lo0'
sa_family: 30
ifr_name: 'lo0'
sa_family: 30
ifr_name: 'gif0'
sa_family: 18
ifr_name: 'stf0'
sa_family: 18
ifr_name: 'XHC20'
sa_family: 18
ifr_name: 'EHC29'
sa_family: 18

[ChristopherHX]

We might need to increase the storage for the host ifconf on macOS, because the list is so much longer than on Linux

[ChristopherHX]

SOCKET_CGIFNETMASK
Needs changes on macOS
ifreq has indeed not the size for storing the to_host addressfamily

oh got this part wrong only accept ipv4 for compatibility.

SIOCGIFCONF also have to return only AF_INET and skip ipv6 etc.for binary compatibility to linux apps

I will close this as fixed with the next release, no errors should happen after latest commits from today.

[ChristopherHX]

Can't keep up.
I might fixed this bug, but this spawened a new one with cxa_guard...

[ChristopherHX]

Has nothing to do with this issue, it is syscall()