[Bug 1511735] Re: libnl: fail to bind() netlink sockets
Ryan Harper
1511735 at bugs.launchpad.net
Wed Dec 16 17:03:28 UTC 2015
Tarball of the test-case used to confirm failure and fix.
** Attachment added: "lp_1511735_test.tar"
https://bugs.launchpad.net/ubuntu/+source/libnl3/+bug/1511735/+attachment/4535781/+files/lp_1511735_test.tar
** Description changed:
- The following upstream patches are needed in order to avoid failures
- when binding a netlink socket:
+ [Impact]
+
+ * Applications in Trusty using libnl-3-200 which frequently open and
+ close netlink sockets can easily fail when attempting to bind the
+ local socket. The problem happens when libnl choose a port id
+ already used by another application and subsequently libnl fails
+ instead of trying another port id.
+
+ The original bug was discovered when attempting to start a virtual
+ machine under libvirt, which is a user of this library.
+
+ * Backporting fixes from upstream release fixes a real bug in the
+ current version of the library in Trusty. The alternative is for all
+ applications to manually manage their local port allocation, or as
+ upstream has accepted allowing libnl to attempt to try for other
+ local ports.
+
+ * All patches applied are already accepted upstream and newer Ubuntu
+ releases are not affected.
+
+ [Test Case]
+
+ * On a Trusty 14.04 system
+ 1. sudo apt-get install libnl-3-200 libnl-3-dev libnl-3-dev \
+ libnl-genl-3-dev libnl-route-3-200 \
+ make gcc build-essential libnl1
+ 2. download and unpack attachment: lp_1511735_test.tar
+ 3. Run testcases:
+
+ % if ./example.sh; then echo "libnl OK"; else echo "libnl FAILED"; fi
+ gcc -o example -I/usr/include/libnl3 example.c -lnl-3 -lnl-genl-3
+ set manually the local port to 6975 (pid: 6974)
+ local port has been set by the libnl to 6975 (pid: 6975)
+ ERROR: genl_connect(): Object exists (local port: 6975, pid: 6975)
+ libnl FAILED
+ % python libnl3-test-rh1249158.py a b c d
+ ulimit(NOFILE) = (2048, 4096)
+ Test: PID=6978
+ TEST (a)...
+ Traceback (most recent call last):
+ File "libnl3-test-rh1249158.py", line 226, in <module>
+ locals()["TEST_" + arg]()
+ File "libnl3-test-rh1249158.py", line 140, in TEST_a
+ sk = nl_get_socket()
+ File "libnl3-test-rh1249158.py", line 115, in nl_get_socket
+ raise IOError(-err, _nl_geterror())
+ OSError: [Errno 6] b'Unspecific failure'
+
+ 4. After applying the updated packages:
+
+ % if ./example.sh; then echo "libnl OK"; else echo "libnl FAILED"; fi
+ gcc -o example -I/usr/include/libnl3 example.c -lnl-3 -lnl-genl-3
+ set manually the local port to 11295 (pid: 11294)
+ local port has been set by the libnl to 2894081055 (pid: 11295)
+ libnl OK
+ % python libnl3-test-rh1249158.py a b c d
+ ulimit(NOFILE) = (2048, 4096)
+ Test: PID=11296
+ TEST (a)...
+ ...done
+ TEST (b)...
+ ...done
+ TEST (c)...
+ ...done
+ TEST (d)...
+ ...done
+
+ [Regression Potential]
+
+ * There are quite a few high profile packages that depend on this package,
+ notably libvirt and network-manager. The complete list is here:
+
+ # on Trusty
+ % apt-rdepends -r libnl-3-200 | head -n 33
+ libnl-3-200
+ Reverse Depends: batctl (>= 2013.4.0-2)
+ Reverse Depends: bmon (>= 1:3.1-1)
+ Reverse Depends: crda (>= 1.1.2-1ubuntu2)
+ Reverse Depends: hostapd (>= 1:2.1-0ubuntu1)
+ Reverse Depends: ipvsadm (>= 1:1.26-2ubuntu1)
+ Reverse Depends: iw (>= 3.4-1)
+ Reverse Depends: keepalived (>= 1:1.2.7-1ubuntu1)
+ Reverse Depends: kismet (>= 2013.03.R1b-3)
+ Reverse Depends: knemo (>= 0.7.6-2)
+ Reverse Depends: libfsobasics3 (>= 0.12.0-4)
+ Reverse Depends: libnetcf1 (>= 1:0.2.3-4ubuntu1)
+ Reverse Depends: libnl-3-200-dbg (= 3.2.21-1)
+ Reverse Depends: libnl-3-dev (= 3.2.21-1)
+ Reverse Depends: libnl-cli-3-200 (= 3.2.21-1)
+ Reverse Depends: libnl-genl-3-200 (= 3.2.21-1)
+ Reverse Depends: libnl-nf-3-200 (= 3.2.21-1)
+ Reverse Depends: libnl-route-3-200 (= 3.2.21-1)
+ Reverse Depends: libnl-utils (>= 3.2.21-1)
+ Reverse Depends: libnss-gw-name (>= 0.3-2)
+ Reverse Depends: libvirt-bin (>= 1.2.2-0ubuntu13)
+ Reverse Depends: libvirt0 (>= 1.2.2-0ubuntu13)
+ Reverse Depends: lowpan-test-tools (>= 0.3-1)
+ Reverse Depends: lowpan-tools (>= 0.3-1)
+ Reverse Depends: neard (>= 0.11-1)
+ Reverse Depends: neard-tools (>= 0.11-1)
+ Reverse Depends: network-manager (>= 0.9.8.8-0ubuntu7)
+ Reverse Depends: ntrack-module-libnl-0 (>= 016-1.2ubuntu2)
+ Reverse Depends: plainbox-provider-resource-generic (>= 0.3-1)
+ Reverse Depends: powertop (>= 2.5-1ubuntu1)
+ Reverse Depends: quota (>= 4.01-3)
+ Reverse Depends: sssd-common (>= 1.11.5-1ubuntu3)
+ Reverse Depends: wpasupplicant (>= 2.1-0ubuntu1)
+
+
+ * This patch does change the default behavoir when asking libnl-3-200
+ to generate local ports. Applications (or libraries) may already
+ have retry code in-place and it's not clear if those applications
+ would break.
+
+
+ [Original Description]
+ The following upstream patches are needed in order to avoid failures when binding a netlink socket:
1f734a8f892a lib/socket: randomize the generated local port
http://git.infradead.org/users/tgr/libnl.git/commitdiff/1f734a8f892a
4dd5fdd0af2c lib/socket: retry generate local port in nl_connect on ADDRINUSE
http://git.infradead.org/users/tgr/libnl.git/commitdiff/4dd5fdd0af2c
027157898708 lib/socket: don't fail if no more local ports can be assigned in nl_socket_alloc
http://git.infradead.org/users/tgr/libnl.git/commitdiff/027157898708
0fd510b3673f lib/socket: use proper typed constant UINT32_MAX for uint32_t typed port
http://git.infradead.org/users/tgr/libnl.git/commitdiff/0fd510b3673f
Without these patches, an application which opens and closes regularly
netlink sockets can easily fails to bind them.
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https://bugs.launchpad.net/bugs/1511735
Title:
libnl: fail to bind() netlink sockets
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