We already check our /proc/`getppid()` fd every time we attach a thread, so
these were unneeded at best. The one that happened after dropping
capabilities was actively wrong, though, because /proc/pid access
checks happen on every operation. (only on some kernels?)
Also, add a check that getppid() doesn't change after opening
/proc/getppid().
Bug: http://b/35241370
Test: debuggerd -b `pidof com.android.bluetooth`
Change-Id: I807439d8c2afd027f3c382face50167a8a7946c4
Do an in-process unwind for processes that have PR_SET_NO_NEW_PRIVS
enabled.
Bug: http://b/34684590
Test: debuggerd_test, killall -ABRT media.codec
Change-Id: I62562ec2c419d6643970100ab1cc0288982a1eed
Set and restore PR_SET_DUMPABLE when performing a dump, so that
processes that have it implicitly cleared (e.g. services that acquire
filesystem capabilities) still get crash dumps.
Bug: http://b/35174939
Test: debuggerd -b `pidof surfaceflinger`
Change-Id: Ife933c10086e546726dec12a7efa3f9cedfeea60
/proc/<pid>/fd is also limited by ptrace_may_access.
Test: manual inspection of "debuggerd -b `pidof zygote`"
Change-Id: I1a28c21c0438fe8729bd8e041c6b418d6a84c586
Reading /proc/<pid>/maps does a ptrace_may_access check, which will
fail if we have fewer capabilities than the target, even if we've
already ptraced it.
Bug: http://b/35070339
Test: debuggerd -b `pidof zygote`
Change-Id: I984a061022bd945a7950b88f6d579e1bd735e893
Dump all of the threads when using `debuggerd -b`.
Bug: http://b/34719257
Test: `debuggerd -b mediaserver`
Change-Id: I2f57100985e5b0c2bf019482ba9feff31921692f
PTRACE_DETACH is only necessary if the process is in group-stop state,
the tracer exiting is sufficient to detach and resume tracees.
Using this, set a 5 second timer with alarm(2) that just kills us, to
avoid leaving processes stopped.
Bug: http://b/34472671
Test: debuggerd_test
Test: crasher + manually inserting a 10 second sleep into crash_dump
Change-Id: Iacaa796f79037aa1585f3f2159abe45ef0069311
ptrace(PTRACE_ATTACH) does not immediately put the traced process in a
stopped state. If we manage to call PTRACE_CONT on it before it
finishes, we'll fail. Switch to using PTRACE_SEIZE and PTRACE_INTERRUPT
to guarantee that the target stops immediately.
This also has the advantage of never putting the process in group-stop
state, which means if we exit prematurely (e.g. if we crash during
stack unwinding), the target process will be resumed without any
intervention needed.
Bug: http://b/34472671
Test: while true; do debuggerd -b `pidof audioserver`; done
Change-Id: I7549f67489646cf300b8c9aa8c735e5e897806ef
crash_dump is a dynamic executable that gets the default crash dumping
handlers set by the linker. Turn them off to prevent crash_dump from
dumping itself.
Bug: http://b/34472671
Test: inserted an abort into crash_dump
Change-Id: Ic9d708805ad47afbb2a9ff37e2ca059f23f421de
A TOCTOU race can occur between listing threads and attaching them.
Don't abort and leave the process in a stopped state when this happens.
Bug: http://b/34472671
Test: while true; do debuggerd -b `pidof audioserver`; done
Change-Id: Ib1632c3423fddf506b5c7874223c82fada78a85e
Remove debuggerd in favor of a helper process that gets execed by
crashing processes.
Bug: http://b/30705528
Test: debuggerd_test
Change-Id: I9906c69473989cbf7fe5ea6cccf9a9c563d75906
