971635 - [seccomp] Seccomp violation when taking a photo on Buri

Status: RESOLVED DUPLICATE of bug 971514

(Firefox OS Graveyard :: General, defect)

Description

[Paul Theriault [:pauljt] (no longer reading bugmail)]

After applying the patch for 970676, I get the camera app crashes when I take a photo. Logcat output looks like:

E/mm-camera(  157): out2CbCrImageHeight = 160
E/mm-camera(  157): out2CbCrImageWidthIn64BitWords = 60
E/mm-camera(  157): out2CbCrBurstLen = 1
E/mm-camera(  157): out2CbCrNumRows = 160
E/mm-camera(  157): out2CbCrRowIncIn64bitIncs = 60
E/mm-camera(  157): axi_config AXI Configuration success 
E/mm-camera(  157): config_MSG_ID_RESET_ACK: 3375
E/mm-camera(  157): config_MSG_ID_RESET_ACK: 3405
E/Sandbox ( 1107): seccomp sandbox violation: pid 1107, syscall 251, args 12 3 3 1139358312 12 1139358312.  Killing process.
I/Gecko   (  645): [Parent 645] WARNING: pipe error (115): Connection reset by peer: file /Volumes/b2gdisk.dmg/B2G/gecko/ipc/chromium/src/chrome/common/ipc_channel_posix.cc, line 445
I/Gecko   (  645): 
I/Gecko   (  645): ###!!! [Parent][MessageChannel] Error: Channel error: cannot send/recv
I/Gecko   (  645): 

I am using a debug build, built a couple hours ago.

Comment 1

[Paul Theriault [:pauljt] (no longer reading bugmail)]

Syscall 251 seems to be __NR_epoll_ctl

Searching through moz-central, Nuwa.cpp uses this:

1222 extern "C" MFBT_API int
1223 __wrap_epoll_ctl(int aEpollFd, int aOp, int aFd, struct epoll_event *aEvent) {
1224   int rv = REAL(epoll_ctl)(aEpollFd, aOp, aFd, aEvent);
1225 
1226   if (!sIsNuwaProcess || rv == -1) {
1227     return rv;
1228   }

There are other uses, but the camera was working yesterday, so maybe this is the culprit.

Comment 2

[Paul Theriault [:pauljt] (no longer reading bugmail)]

Link for above code: http://mxr.mozilla.org/mozilla-central/source/mozglue/build/Nuwa.cpp#1224

Comment 3

[Paul Theriault [:pauljt] (no longer reading bugmail)]

Seccomp filter does not whitelist epoll_ctl. I allows epoll_wait though:

http://mxr.mozilla.org/mozilla-central/source/security/sandbox/linux/seccomp_filter.h#120

Comment 4

[Stephanie Ouillon [:arroway] (needinfo me)]

I try building the same version of gecko but without applying jld's patch (see bug 970676), and I don't get any crash.

Comment 5

[Jed Davis [:jld] ⟨⏰|UTC-7⟩ ⟦he/him⟧]

Sorry; I ran into this myself and analyzed it but forgot to update the patch.