[Bug 1922102] [NEW] Broken tap networking on macOS host

[Vladislav Yaroshchuk]

Public bug reported:

Building QEMU with GLib newer than 2.58.3 corrupts tap networking on macOS 
hosts.
Tap device was provided by Tun/Tap kernel extension installed from brew:
  brew install tuntap

Checked revisions:
  553032d (v5.2.0)
  6d40ce0 (v6.0.0-rc1)

Host:
 MacBook Pro (Retina, 15-inch, Mid 2015)
 macOS Catalina 10.15.6 (19G2021)

Guest:
  Linux Ubuntu 4.4.0-206-generic x86_64
  Also tested macOS Catalina 10.15.7 as a guest, the behaviour is the same.

QEMU command line:

qemu-system-x86_64 \
  -drive file=hdd.qcow2,if=virtio,format=qcow2 \
  -m 3G \
  -nic tap,script=tap-up.sh

tap-up.sh:

 #!/bin/sh

 TAPDEV="$1"
 BRIDGEDEV="bridge0"

 ifconfig "$BRIDGEDEV" addm "$TAPDEV"

Enabling/disabling Hypervisor.Framework acceleration (`-accel hvf`) has
no effect.

How to reproduce:
  1. Build & install GLib > 2.58.3 (tested 2.60.7, 2.60.7)
  2. Build qemu-system-x86_64 with GLib > 2.58.3
  3. Boot any guest any guest with tap networking enabled
  4. See that the external network is inaccessible

Hotfix:
  1. Build & install GLib 2.58.3
  2. Build qemu-system-x86_64 with GLib 2.58.3
  3. Boot any guest with tap networking enabled
  4. See that the external network is accessible, everything is working as 
expected

** Affects: qemu
     Importance: Undecided
         Status: New


** Tags: macos net network tap tap-net

** Description changed:

- Building QEMU with GLib newer than 2.58.3 corrupts tap networking. 
+ Building QEMU with GLib newer than 2.58.3 corrupts tap networking on macOS 
hosts.
  Tap device was provided by Tun/Tap kernel extension installed from brew:
-   brew install tuntap
+   brew install tuntap
  
  Checked revisions:
-   553032d (v5.2.0)
-   6d40ce0 (v6.0.0-rc1)
+   553032d (v5.2.0)
+   6d40ce0 (v6.0.0-rc1)
  
  Host:
-  MacBook Pro (Retina, 15-inch, Mid 2015)
-  macOS Catalina 10.15.6 (19G2021)
+  MacBook Pro (Retina, 15-inch, Mid 2015)
+  macOS Catalina 10.15.6 (19G2021)
  
  Guest:
-   Linux Ubuntu 4.4.0-206-generic x86_64
-   Also tested macOS Catalina 10.15.7 as a guest, the behaviour is the same.
+   Linux Ubuntu 4.4.0-206-generic x86_64
+   Also tested macOS Catalina 10.15.7 as a guest, the behaviour is the same.
  
  QEMU command line:
  
  qemu-system-x86_64 \
-   -drive file=hdd.qcow2,if=virtio,format=qcow2 \
-   -m 3G \
-   -nic tap,script=tap-up.sh
+   -drive file=hdd.qcow2,if=virtio,format=qcow2 \
+   -m 3G \
+   -nic tap,script=tap-up.sh
  
  tap-up.sh:
-  
-  #!/bin/sh
  
-  TAPDEV="$1"
-  BRIDGEDEV="bridge0"
+  #!/bin/sh
  
-  ifconfig "$BRIDGEDEV" addm "$TAPDEV"
+  TAPDEV="$1"
+  BRIDGEDEV="bridge0"
+ 
+  ifconfig "$BRIDGEDEV" addm "$TAPDEV"
  
  Enabling/disabling Hypervisor.Framework acceleration (`-accel hvf`) has
  no effect.
  
- How to reproduce: 
-   1. Build & install GLib > 2.58.3 (tested 2.60.7, 2.60.7)
-   2. Build qemu-system-x86_64 with GLib > 2.58.3
-   3. Boot any guest any guest with tap networking enabled
-   4. See that the external network is inaccessible
+ How to reproduce:
+   1. Build & install GLib > 2.58.3 (tested 2.60.7, 2.60.7)
+   2. Build qemu-system-x86_64 with GLib > 2.58.3
+   3. Boot any guest any guest with tap networking enabled
+   4. See that the external network is inaccessible
  
  Hotfix:
-   1. Build & install GLib 2.58.3
-   2. Build qemu-system-x86_64 with GLib 2.58.3
-   3. Boot any guest with tap networking enabled
-   4. See that the external network is accessible, everything is working as 
expected
+   1. Build & install GLib 2.58.3
+   2. Build qemu-system-x86_64 with GLib 2.58.3
+   3. Boot any guest with tap networking enabled
+   4. See that the external network is accessible, everything is working as 
expected

-- 
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https://bugs.launchpad.net/bugs/1922102

Title:
  Broken tap networking on macOS host

Status in QEMU:
  New

Bug description:
  Building QEMU with GLib newer than 2.58.3 corrupts tap networking on macOS 
hosts.
  Tap device was provided by Tun/Tap kernel extension installed from brew:
    brew install tuntap

  Checked revisions:
    553032d (v5.2.0)
    6d40ce0 (v6.0.0-rc1)

  Host:
   MacBook Pro (Retina, 15-inch, Mid 2015)
   macOS Catalina 10.15.6 (19G2021)

  Guest:
    Linux Ubuntu 4.4.0-206-generic x86_64
    Also tested macOS Catalina 10.15.7 as a guest, the behaviour is the same.

  QEMU command line:

  qemu-system-x86_64 \
    -drive file=hdd.qcow2,if=virtio,format=qcow2 \
    -m 3G \
    -nic tap,script=tap-up.sh

  tap-up.sh:

   #!/bin/sh

   TAPDEV="$1"
   BRIDGEDEV="bridge0"

   ifconfig "$BRIDGEDEV" addm "$TAPDEV"

  Enabling/disabling Hypervisor.Framework acceleration (`-accel hvf`)
  has no effect.

  How to reproduce:
    1. Build & install GLib > 2.58.3 (tested 2.60.7, 2.60.7)
    2. Build qemu-system-x86_64 with GLib > 2.58.3
    3. Boot any guest any guest with tap networking enabled
    4. See that the external network is inaccessible

  Hotfix:
    1. Build & install GLib 2.58.3
    2. Build qemu-system-x86_64 with GLib 2.58.3
    3. Boot any guest with tap networking enabled
    4. See that the external network is accessible, everything is working as 
expected

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