`1 << 32` overflows, resulting in bogus PR_CAP_AMBIENT_RAISE attempts,
and breaking dumping for processes with capabilities in the top 32 bits.
Bug: http://b/35241370
Test: debuggerd -b `pidof com.android.bluetooth`
Change-Id: I29c45a8bd36bdeb3492c9f74599993c139821088
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
snprintf isn't safe to call in the linker after initialization, because
it uses MB_CUR_MAX which is implemented via pthread_getspecific, which
uses TLS slots shared with libc. If the TLS slots are assigned in a
different order between libc.so and the linker, MB_CUR_MAX will
evaluate to an incorrect value, and lead to snprintf doing bad things.
Switch to __libc_format_buffer.
Bug: http://b/35367169
Test: debuggerd -b `pidof zygote`
Change-Id: I9d315cf63e5f3fd2f4545d6e3f707cdbe94ec606
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
Raise CapInh and CapAmb after forking to exec crash_dump, so that it
can ptrace us.
Bug: http://b/35174939
Test: debuggerd -b `pidof surfaceflinger`
Change-Id: I32567010a3603cfa494aae9dc0e3ce73fb86b590
waitpid(..., __WCLONE) fails with ECHILD when passed an explicit PID to
wait for. __WALL and __WCLONE don't seem to be necessary when waiting
for a specific pid, so just pass 0 in the flags instead.
Bug: http://b/35327712
Test: /data/nativetest/debuggerd_test/debuggerd_test32 --gtest_filter="*zombie*"
Change-Id: I3dd7a1bdf7ff35fdfbf631429c089ef4e3172855
/proc/<pid>/fd is also limited by ptrace_may_access.
Test: manual inspection of "debuggerd -b `pidof zygote`"
Change-Id: I1a28c21c0438fe8729bd8e041c6b418d6a84c586
https://android-review.googlesource.com/#/c/331200 moved crasher to
using soong, which changed its location from /system/xbin/crasher to
/system/bin/crasher.
Bug: http://b/35100742
Test: /data/nativetest/debuggerd_test/debuggerd_test32
Test: /data/nativetest64/debuggerd_test/debuggerd_test64
Change-Id: I16a2050b257277023773cc0c960b5ab36e0c7cd4
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
Fixed this when I tested on internal, but failed to copy the fix over
when submitting to AOSP.
Bug: http://b/35070339
Test: `adb bugreport` on angler
Change-Id: Ib84d212e5f890958cd21f5c018fbc6f368138d1e
* changes:
debuggerd_handler: don't use clone(..., SIGCHLD, ...)
crash_dump: drop capabilities after we ptrace attach.
crash_dump: use /proc/<pid> fd to check tid process membership.
debuggerd_handler: raise ambient capset before execing.
Revert "Give crash_dump CAP_SYS_PTRACE."
Processes that handle SIGCHLD can race with the crash handler to wait
on the crash_dump process. Use clone flags that cause the forked
child's death to not be reported via SIGCHLD, and don't bail out of
dumping when waitpid returns ECHILD (in case another thread is already
in a waitpid(..., __WALL))
Note that the use of waitid was switched to waitpid, because waitid
doesn't support __WCLONE until kernel version 4.7.
Bug: none
Test: "debuggerd -b `pidof zygote64`" a few times (failed roughly 50%
of the time previously)
Change-Id: Ia41a26a61f13c6f9aa85c4c2f88aef8d279d35ad
Raise the ambient capability set to match CapEff so that crash_dump can
inherit all of the capabilities of the dumped process to be able to
ptrace. Note that selinux will prevent crash_dump from actually use
any of the capabilities.
Bug: http://b/34853272
Test: debuggerd -b `pidof system_server`
Test: debuggerd -b `pidof zygote`
Change-Id: I1fe69eff54c1c0a5b3ec63f6fa504b2681c47a88
Dump all of the threads when using `debuggerd -b`.
Bug: http://b/34719257
Test: `debuggerd -b mediaserver`
Change-Id: I2f57100985e5b0c2bf019482ba9feff31921692f
We can't do an selinux transition when this is on.
Bug: http://b/34472671
Test: logcat -c; debuggerd `pidof media.codec`; logcat
Change-Id: Ie6c1832ab838df48879c32a86126862de9a15420
Actually exit when receiving a signal via kill(2) or raise(2) and
PR_GET_DUMPABLE is 0.
Bug: none
Test: /data/nativetest/debuggerd_test/debuggerd_test32
Test: /data/nativetest64/bionic-unit-tests/bionic-unit-tests --gtest_filter=pthread_DeathTest.pthread_mutex_lock_null_64
Change-Id: I833a2a34238129237bd9f953959ebda51d8d04d7
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
Occasionally, the pseudothread wouldn't exit in time after unlocking
the mutex to get crash_dump to proceed, resulting in spurious error
messages. Instead of using a mutex to emulate pthread_join, just
implement it correctly.
Bug: http://b/34472671
Test: debuggerd_test
Change-Id: I5c2658a84e9407ed8cc0ef2ad0fb648c388b7ad1
