ACPR/android_system_core
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crash_dump: drop capabilities after we ptrace attach.

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Bug: http://b/34853272
Test: debuggerd -b `pidof system_server`
Test: debuggerd -b `pidof zygote`
Change-Id: Ic1e1a4b0eb1f561621800cd4cc9a5b848fc5ffd8
This commit is contained in:
Josh Gao 2017-02-01 16:35:31 -08:00
parent fe90276aee
commit 85bcaf68d3
1 changed files with 24 additions and 1 deletions
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25
debuggerd/crash_dump.cpp
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@ -18,10 +18,12 @@
#include <dirent.h>
#include <fcntl.h>
#include <stdlib.h>
#include <syscall.h>
#include <sys/capability.h>
#include <sys/prctl.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <sys/un.h>
#include <syscall.h>
#include <unistd.h>
#include <limits>
@ -191,6 +193,24 @@ static void abort_handler(pid_t target, const bool& tombstoned_connected,
_exit(1);
}
static void drop_capabilities() {
__user_cap_header_struct capheader;
memset(&capheader, 0, sizeof(capheader));
capheader.version = _LINUX_CAPABILITY_VERSION_3;
capheader.pid = 0;
__user_cap_data_struct capdata[2];
memset(&capdata, 0, sizeof(capdata));
if (capset(&capheader, &capdata[0]) == -1) {
PLOG(FATAL) << "failed to drop capabilities";
}
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) != 0) {
PLOG(FATAL) << "failed to set PR_SET_NO_NEW_PRIVS";
}
}
static void check_process(int proc_fd, pid_t expected_pid) {
android::procinfo::ProcessInfo proc_info;
if (!android::procinfo::GetProcessInfoFromProcPidFd(proc_fd, &proc_info)) {
@ -338,6 +358,9 @@ int main(int argc, char** argv) {
}
}
// Drop our capabilities now that we've attached to the threads we care about.
drop_capabilities();
check_process(target_proc_fd, target);
// TODO: Use seccomp to lock ourselves down.