Public bug reported:
Hi
As a developer, while trying to get the wpa_supplicant status by using
wpa_cli, it always returns a timeout from the snap context on Ubuntu
Core 20.
The problem is not reproducible with Ubuntu Classic.
I did some further analysis to get strace output of `wpa_cli` as well as
`wpa_supplicant` for the good (running wpa_cli from host terminal) and
bad (running from snap context) cases.
Here is the strace output of the wpa_cli;
Good case:
```
bind(3, {sa_family=AF_UNIX, sun_path="/tmp/wpa_ctrl_29279-1"}, 110) = 0
connect(3, {sa_family=AF_UNIX, sun_path="/var/run/wpa_supplicant/wlp0s20f3"},
110) = 0
fcntl(3, F_GETFL) = 0x2 (flags O_RDWR)
fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0
sendto(3, "STATUS", 6, 0, NULL, 0) = 6
pselect6(4, [3], NULL, NULL, {tv_sec=10, tv_nsec=0}, NULL) = 1 (in [3], left
{tv_sec=9, tv_nsec=999998877})
recvfrom(3, "bssid=68:a0:3e:93:47:2f\nfreq=526"..., 4095, 0, NULL, NULL) = 316
newfstatat(1, "", {st_mode=S_IFCHR|0620, st_rdev=makedev(0x88, 0x4), ...},
AT_EMPTY_PATH) = 0
write(1, "bssid=68:a0:3e:93:47:2f\n", 24bssid=68:a0:3e:93:47:2f
) = 24
write(1, "freq=5260\n", 10freq=5260
) = 10
write(1, "ssid=SUPERBOX_Wi-Fi_472B\n", 25ssid=SUPERBOX_Wi-Fi_472B
) = 25
write(1, "id=0\n", 5id=0
) = 5
write(1, "mode=station\n", 13mode=station
) = 13
write(1, "wifi_generation=5\n", 18wifi_generation=5
) = 18
write(1, "pairwise_cipher=CCMP\n", 21pairwise_cipher=CCMP
) = 21
write(1, "group_cipher=CCMP\n", 18group_cipher=CCMP
) = 18
write(1, "key_mgmt=WPA2-PSK\n", 18key_mgmt=WPA2-PSK
) = 18
write(1, "wpa_state=COMPLETED\n", 20wpa_state=COMPLETED
) = 20
write(1, "ip_address=192.168.1.101\n", 25ip_address=192.168.1.101
) = 25
write(1, "p2p_device_address=b0:a4:60:e0:0"...,
37p2p_device_address=b0:a4:60:e0:0c:91
) = 37
write(1, "address=b0:a4:60:e0:0c:90\n", 26address=b0:a4:60:e0:0c:90
) = 26
write(1, "uuid=962ca758-c0a7-54c0-ae01-689"...,
42uuid=962ca758-c0a7-54c0-ae01-68990801f7a0
) = 42
write(1, "ieee80211ac=1\n", 14ieee80211ac=1
) = 14
unlink("/tmp/wpa_ctrl_29279-1") = 0
close(3) = 0
exit_group(0) = ?
```
Bad case (running from the snap context)
```
getpid() = 58024
bind(3, {sa_family=AF_UNIX, sun_path="/tmp/wpa_ctrl_58024-1"}, 110) = 0
connect(3, {sa_family=AF_UNIX, sun_path="/var/run/wpa_supplicant/wlp0s20f3"},
110) = 0
fcntl(3, F_GETFL) = 0x2 (flags O_RDWR)
fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0
sendto(3, "STATUS", 6, 0, NULL, 0) = 6
fstat(1, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0
unlink("/tmp/wpa_ctrl_58024-1") = 0
close(3) = 0
write(1, "'STATUS' command timed out.\n", 28'STATUS' command timed out.
) = 28
exit_group(-2) = ?
+++ exited with 254 +++
```
Here is the wpa_supplicant strace output;
For the good case, wpa_supplicant was able to send the message back to
the wpa_cli;
```
pselect6(19, [4 5 7 9 10 11 13 14 15 16 17 18], [], [4], {tv_sec=9,
tv_nsec=999997000}, NULL) = 1 (in [14], left {tv_sec=9, tv_nsec=281454971})
recvfrom(14, "STATUS", 8193, 0, {sa_family=AF_UNIX,
sun_path="/tmp/wpa_ctrl_172293-1"}, [128 => 25]) = 6
getsockopt(14, SOL_SOCKET, SO_SNDBUF, [212992], [4]) = 0
ioctl(14, TIOCOUTQ, [0]) = 0
socket(AF_INET, SOCK_DGRAM, IPPROTO_IP) = 19
ioctl(19, SIOCGIFADDR, {ifr_name="wlp0s20f3", ifr_addr={sa_family=AF_INET,
sin_port=htons(0), sin_addr=inet_addr("192.168.1.101")}}) = 0
close(19) = 0
getsockopt(14, SOL_SOCKET, SO_SNDBUF, [212992], [4]) = 0
ioctl(14, TIOCOUTQ, [0]) = 0
sendto(14, "bssid=68:a0:3e:93:47:2f\nfreq=526"..., 316, 0, {sa_family=AF_UNIX,
sun_path="/tmp/wpa_ctrl_172293-1"}, 25) = 316
pselect6(19, [4 5 7 9 10 11 13 14 15 16 17 18], [], [4], {tv_sec=9,
tv_nsec=278742000}, NULL
```
However, for the bad case (where wpa_cli is called from the snap
context), the data is available but while wpa_supplicant tries to send
it, the socket is probably not visible since we got a no such a file
error;
```
recvfrom(14, "STATUS", 8193, 0, {sa_family=AF_UNIX,
sun_path="/tmp/wpa_ctrl_172203-1"}, [128 => 25]) = 6
getsockopt(14, SOL_SOCKET, SO_SNDBUF, [212992], [4]) = 0
ioctl(14, TIOCOUTQ, [0]) = 0
socket(AF_INET, SOCK_DGRAM, IPPROTO_IP) = 19
ioctl(19, SIOCGIFADDR, {ifr_name="wlp0s20f3", ifr_addr={sa_family=AF_INET,
sin_port=htons(0), sin_addr=inet_addr("192.168.1.101")}}) = 0
close(19) = 0
getsockopt(14, SOL_SOCKET, SO_SNDBUF, [212992], [4]) = 0
ioctl(14, TIOCOUTQ, [0]) = 0
sendto(14, "bssid=68:a0:3e:93:47:2f\nfreq=526"..., 316, 0, {sa_family=AF_UNIX,
sun_path="/tmp/wpa_ctrl_172203-1"}, 25) = -1 ENOENT (No such file or directory)
getsockopt(14, SOL_SOCKET, SO_SNDBUF, [212992], [4]) = 0
ioctl(14, TIOCOUTQ, [0]) = 0
```
I dont see any denial for accessing to the unix socket and the same problem
also occurs within devmode.
I'm assuming that since all of the snaps have their own `/tmp` directory, they
may not be able to reach out to the `/tmp` of the host. Moreover, it seems like
the wpa_cli also opens a unix socket that exist within the `/tmp` directory.
Thus, we might be observing this behavior.
Could you please suggest a potential fixes?
Thanks,
Bugra
** Affects: wpa (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2074070
Title:
unable to get WPA supplicant status via wpa-cli utility from a snap
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