Bug#1060285: mptcpd: FTBFS with a segmentation fault in the testsuite when SCTP disabled and no /etc/protocols
Source: mptcpd
Version: 0.12-2
Severity: serious
Tags: ftbfs upstream
Justification: fails to build from source (but built successfully in the past)
User: debian-riscv@lists.debian.org
Usertags: riscv64
X-Debbugs-Cc: debian-riscv@lists.debian.org
Dear maintainer,
On riscv64, mptcpd fails to build from source with a segmentation fault
in the test-mptcpwrap test:
| =======================================
| mptcpd 0.12: tests/test-suite.log
| =======================================
|
| # TOTAL: 19
| # PASS: 17
| # SKIP: 1
| # XFAIL: 0
| # FAIL: 1
| # XPASS: 0
| # ERROR: 0
|
| .. contents:: :depth: 2
|
| SKIP: test-start-stop
| =====================
|
| Running non-interactive sudo check...
| sudo: a password is required
| fail, skipping the test
| SKIP test-start-stop (exit status: 77)
|
| FAIL: test-mptcpwrap
| ====================
|
| Test case 0: PASS
| Test case 1: Segmentation fault
| FAIL test-mptcpwrap (exit status: 139)
A full build log is available here:
https://buildd.debian.org/status/fetch.php?pkg=mptcpd&arch=riscv64&ver=0.12-2%2Bb1&stamp=1704714971&raw=0
Investigation shows that 3 conditions are needed to trigger this issue:
- A recent kernel that supports mptcp, to be checked with
/proc/sys/net/mptcp/enabled
- Something that prevents SCTP to be used, for instance on the build
daemons /proc/sys/kernel/modules_disabled is set to 1, preventing the
sctp.ko module to be loaded
- A system without /etc/protocols, for instance without the netbase
package installed.
With this three conditions, this triggers the following code path from
the mptcpwrap-tester.c file:
| static void test_socket_data(struct socket_data const *data)
| {
| int const fd = socket(data->domain, data->type, data->protocol);
|
| if (fd == -1) {
| if (errno == EPROTONOSUPPORT) {
| struct protoent const *const p =
| getprotobynumber(data->protocol);
|
| fprintf(stderr,
| "WARNING: Ignoring unsupported "
| "protocol: %d - %s\n",
| data->protocol,
| p->p_name);
|
| return;
| }
The output of getprotobynumber() is used directly, without checking for
a NULL pointer in case of error, for instance because /etc/protocols
does not exist. This causes a segmentation fault when trying to
dereference it. A workaround is to build-depends on netbase, and a
proper fix to test for this error.
In the latest rebuild of mptpcd, the conditions where met only on the
riscv64 buildd, and riscv64 is not a release architecture. That said a
few mips64el buildds also met the 3 conditions and it will be the case
of more and more buildds once they are upgraded to bookworm. I am
therefore filling this issue as severity serious.
Regards
Aurelien
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