Cannot connect to KeePassXC

[rmbellovin]

I am running the deb version of firefox 121 on a fresh install of Ubuntu 23.10; I installed the KeePassXC-browser extension, but it says Cannot connect to KeePassXC. Check that browser integration is enabled in KeePassXC settings. When I click Reload, it says Cannot complete key exchange.

keepassxc-proxy is not running, but trying to launch it manually does not change this behavior. The output of sudo strace -f -p $(pgrep firefox) 2>&1 | grep keepass is

[pid  5891] newfstatat(AT_FDCWD, "/usr/bin/keepassxc-proxy",  <unfinished ...>
[pid  5891] newfstatat(AT_FDCWD, "/usr/bin/keepassxc-proxy",  <unfinished ...>
[pid  5891] newfstatat(AT_FDCWD, "/usr/bin/keepassxc-proxy",  <unfinished ...>
[pid  5891] newfstatat(AT_FDCWD, "/usr/bin/keepassxc-proxy",  <unfinished ...>
[pid  5891] newfstatat(AT_FDCWD, "/usr/bin/keepassxc-proxy",  <unfinished ...>
[pid 16267] execve("/usr/bin/keepassxc-proxy", ["/usr/bin/keepassxc-proxy", "/home/rmb/.mozilla/native-messag"..., "[email protected]"], 0x7ff5fdb7ac20 /* 61 vars */ <unfinished ...>
[pid  2083] <... recvmsg resumed>{msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\7\0\0\200\4\0\377\377childId\0-\0\0\200\4\0\377\377keepassx"..., iov_len=4096}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, MSG_DONTWAIT) = 4096
[pid  2083] recvmsg(110, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\7\0\0\200\4\0\377\377childId\0-\0\0\200\4\0\377\377keepassx"..., iov_len=4096}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, MSG_DONTWAIT) = 2428
[pid  2083] <... recvmsg resumed>{msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\7\0\0\200\4\0\377\377childId\0-\0\0\200\4\0\377\377keepassx"..., iov_len=4096}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, MSG_DONTWAIT) = 4096
[pid  2083] <... recvmsg resumed>{msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\7\0\0\200\4\0\377\377childId\0-\0\0\200\4\0\377\377keepassx"..., iov_len=4096}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, MSG_DONTWAIT) = 4096
[pid  2083] <... recvmsg resumed>{msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="[email protected]\0\6\0\0\200\4\0\377\377hold"..., iov_len=4096}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, MSG_DONTWAIT) = 4096
[pid  2083] <... recvmsg resumed>{msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="r/[email protected]"..., iov_len=4096}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, MSG_DONTWAIT) = 4096
[pid  2083] <... recvmsg resumed>{msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\7\0\0\200\4\0\377\377childId\0-\0\0\200\4\0\377\377keepassx"..., iov_len=4096}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, MSG_DONTWAIT) = 4096
[pid  2083] <... recvmsg resumed>{msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="[email protected]\0\6\0\0\200\4\0\377\377hold"..., iov_len=4096}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, MSG_DONTWAIT) = 4096
[pid  2083] <... recvmsg resumed>{msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\7\0\0\200\4\0\377\377childId\0-\0\0\200\4\0\377\377keepassx"..., iov_len=4096}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, MSG_DONTWAIT) = 4096

I have tried disabling integration, removing the extension, and rebooting.

The browser integration is running on an old laptop running the same versions of firefox, keepassxc, and keepassxc-browser but Ubuntu 22.04; interestingly, a few weeks ago I started having to click reload on the browser extension after every suspend/resume on that laptop.

Debug info

[Error ] KeePassXC-Browser - Failed to connect: Unknown error [global.js:145:13](moz-extension://ae45d0a9-344e-4581-99a9-84179cd9f2be/common/global.js)
[Error client.js:386] KeePassXC-Browser - No content script available for this tab. [global.js:145:13](moz-extension://ae45d0a9-344e-4581-99a9-84179cd9f2be/common/global.js)
[Error keepass.js:811] KeePassXC-Browser - 9: Key exchange was not successful. [global.js:145:13](moz-extension://ae45d0a9-344e-4581-99a9-84179cd9f2be/common/global.js)
[Error keepass.js:421] KeePassXC-Browser - No content script available for this tab. [global.js:145:13](moz-extension://ae45d0a9-344e-4581-99a9-84179cd9f2be/common/global.js)```
KeePassXC - 2.7.6
KeePassXC-Browser - 1.8.10
Operating system: Ubuntu 23.10
Browser: Firefox 121.0

[varjolintu]

Did you check the AppArmor settings from the Troubleshooting Guide?
https://github.com/keepassxreboot/keepassxc-browser/wiki/Troubleshooting-guide#6-apparmor-with-ubuntu

[plocharz-9livesdata]

I had the same problem today, and I've noticed that firefox has updates itself to version from snap. @rmbellovin can you check if you have snap version installed?

[varjolintu]

To check this, go to about:support and check the value of Application Binary.

[jhard]

FYI: possibly unrelated, but I experienced the same on a fresh install on 22.04 and none of the debugging tips produced anything that made sense to me. The proxy would start, but the connection would fail.

What did eventually work was not using firefox deb but instead installing the snap version (pretty much the opposite of what's recommended in most issues) and then applying the flatpak permission tips from #1426.

[droidmonkey]

@jhard that means you did not perform the AppArmor troubleshooting action correctly with your deb install.

[varjolintu]

I'm closing this as a duplicate. Please continue the discussion in the pinned issue: #1863.