1754797 - Assert in nricectx.cpp due to invalid subscript

Status: RESOLVED FIXED

(Core :: WebRTC: Signaling, defect, P2)

Description

[Jan Alexander Steffens [:heftig]]

Attempting to start a WebRTC peer connection (e.g. via https://webrtc.github.io/samples/src/content/peerconnection/audio/) causes the Socket Process to crash with an assert.

/usr/include/c++/11.1.0/bits/stl_vector.h:1045: std::vector::reference std::vector<nr_ice_stun_server_>::operator[](std::vector::size_type) [_Tp = nr_ice_stun_server_, _Alloc = std::allocator<nr_ice_stun_server_>]: Assertion '__n < this->size()' failed.
Redirecting call to abort() to mozalloc_abort

See e.g. bp-6ccca384-8c51-471b-aeb3-465460220210, which points us at nricectx.cpp:812. servers[0] is invalid when servers is empty.

This is only happening because we compile with stdlib assertions enabled (CXXFLAGS contains -Wp,-D_GLIBCXX_ASSERTIONS).

Bug 1253706, specifically 3bbb2706fe05 removed the guards that presumably kept this from exploding before.

Comment 1

[Jan Alexander Steffens [:heftig]]

Some other lines, nricectx.cpp:265 and nricectx.cpp:921 correctly turn an empty vector into a nullptr instead of trying to subscript it like SetStunServers and SetTurnServers do.

Comment 2

[Byron Campen [:bwc]]

The right fix here is probably to use servers.data() instead of &servers[0]

Comment 3

[Byron Campen [:bwc]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=4f683d017c945aae58951ba4acaa28c0902322a0
https://treeherder.mozilla.org/#/jobs?repo=try&revision=a435927ed466e0d3cc5a4ac1da66871144c7e55e
https://treeherder.mozilla.org/#/jobs?repo=try&revision=122ec5ac409e12095254a74793946500e40295c7

Comment 4

[Byron Campen [:bwc]]

Attachment: Bug 1754797: Use .data() instead of subscripting at 0. r?mjf

Comment 5

[Byron Campen [:bwc]]

Try looks good.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a7d2fd1431db
Use .data() instead of subscripting at 0. r=mjf,heftig

Comment 7

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/a7d2fd1431db

Comment 8

[BugBot [:suhaib / :marco]]

Set release status flags based on info from the regressing bug 1253706