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Merge "Better seccomp/kuser_helper diagnostics from debuggerd."

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This commit is contained in:
Elliott Hughes 2017-02-02 17:37:24 +00:00 committed by Gerrit Code Review
commit f4ae6203a9
5 changed files with 164 additions and 78 deletions
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4
debuggerd/Android.bp
View file

@ -195,3 +195,7 @@ cc_binary {
init_rc: ["tombstoned/tombstoned.rc"]
}
subdirs = [
"crasher",
]

81
debuggerd/crasher/Android.bp Normal file
View file

@ -0,0 +1,81 @@
cc_defaults {
name: "crasher-defaults",
cppflags: [
"-std=gnu++14",
"-W",
"-Wall",
"-Wextra",
"-Wunused",
"-Werror",
"-O0",
"-fstack-protector-all",
"-Wno-free-nonheap-object",
"-Wno-date-time",
],
srcs: ["crasher.cpp"],
arch: {
arm: {
srcs: ["arm/crashglue.S"],
armv7_a_neon: {
asflags: ["-DHAS_VFP_D32"],
},
},
arm64: {
srcs: ["arm64/crashglue.S"],
},
mips: {
srcs: ["mips/crashglue.S"],
},
mips64: {
srcs: ["mips64/crashglue.S"],
},
x86: {
srcs: ["x86/crashglue.S"],
},
x86_64: {
srcs: ["x86_64/crashglue.S"],
},
},
compile_multilib: "both",
}
cc_binary {
name: "crasher",
defaults: ["crasher-defaults"],
shared_libs: [
"libbase",
"liblog",
],
multilib: {
lib32: {
stem: "crasher",
},
lib64: {
stem: "crasher64",
},
},
}
cc_binary {
name: "static_crasher",
defaults: ["crasher-defaults"],
cppflags: ["-DSTATIC_CRASHER"],
static_executable: true,
static_libs: [
"libdebuggerd_handler",
"libbase",
"liblog",
],
multilib: {
lib32: {
stem: "static_crasher",
},
lib64: {
stem: "static_crasher64",
},
},
}

66
debuggerd/crasher/Android.mk
View file

@ -1,66 +0,0 @@
LOCAL_PATH := $(call my-dir)
crasher_cppflags := \
-std=gnu++14 \
-W \
-Wall \
-Wextra \
-Wunused \
-Werror \
-O0 \
-fstack-protector-all \
-Wno-free-nonheap-object \
-Wno-date-time
include $(CLEAR_VARS)
LOCAL_SRC_FILES := crasher.cpp
LOCAL_SRC_FILES_arm := arm/crashglue.S
LOCAL_SRC_FILES_arm64 := arm64/crashglue.S
LOCAL_SRC_FILES_mips := mips/crashglue.S
LOCAL_SRC_FILES_mips64 := mips64/crashglue.S
LOCAL_SRC_FILES_x86 := x86/crashglue.S
LOCAL_SRC_FILES_x86_64 := x86_64/crashglue.S
LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES)
LOCAL_MODULE_TAGS := optional
LOCAL_CPPFLAGS := $(crasher_cppflags)
LOCAL_SHARED_LIBRARIES := libbase liblog
# The arm emulator has VFP but not VFPv3-D32.
ifeq ($(ARCH_ARM_HAVE_VFP_D32),true)
LOCAL_ASFLAGS_arm += -DHAS_VFP_D32
endif
LOCAL_MODULE := crasher
LOCAL_MODULE_STEM_32 := crasher
LOCAL_MODULE_STEM_64 := crasher64
LOCAL_MULTILIB := both
include $(BUILD_EXECUTABLE)
include $(CLEAR_VARS)
LOCAL_SRC_FILES := crasher.cpp
LOCAL_SRC_FILES_arm := arm/crashglue.S
LOCAL_SRC_FILES_arm64 := arm64/crashglue.S
LOCAL_SRC_FILES_mips := mips/crashglue.S
LOCAL_SRC_FILES_mips64 := mips64/crashglue.S
LOCAL_SRC_FILES_x86 := x86/crashglue.S
LOCAL_SRC_FILES_x86_64 := x86_64/crashglue.S
LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES)
LOCAL_MODULE_TAGS := optional
LOCAL_CPPFLAGS := $(crasher_cppflags) -DSTATIC_CRASHER
LOCAL_FORCE_STATIC_EXECUTABLE := true
LOCAL_SHARED_LIBRARIES := libbase liblog
# The arm emulator has VFP but not VFPv3-D32.
ifeq ($(ARCH_ARM_HAVE_VFP_D32),true)
LOCAL_ASFLAGS_arm += -DHAS_VFP_D32
endif
LOCAL_MODULE := static_crasher
LOCAL_MODULE_STEM_32 := static_crasher
LOCAL_MODULE_STEM_64 := static_crasher64
LOCAL_MULTILIB := both
LOCAL_STATIC_LIBRARIES := libdebuggerd_handler libbase liblog
include $(BUILD_EXECUTABLE)

43
debuggerd/crasher/crasher.cpp
View file

@ -36,6 +36,19 @@
#include "debuggerd/handler.h"
#endif
#if defined(__arm__)
// See https://www.kernel.org/doc/Documentation/arm/kernel_user_helpers.txt for details.
#define __kuser_helper_version (*(int32_t*) 0xffff0ffc)
typedef void * (__kuser_get_tls_t)(void);
#define __kuser_get_tls (*(__kuser_get_tls_t*) 0xffff0fe0)
typedef int (__kuser_cmpxchg_t)(int oldval, int newval, volatile int *ptr);
#define __kuser_cmpxchg (*(__kuser_cmpxchg_t*) 0xffff0fc0)
typedef void (__kuser_dmb_t)(void);
#define __kuser_dmb (*(__kuser_dmb_t*) 0xffff0fa0)
typedef int (__kuser_cmpxchg64_t)(const int64_t*, const int64_t*, volatile int64_t*);
#define __kuser_cmpxchg64 (*(__kuser_cmpxchg64_t*) 0xffff0f60)
#endif
#define noinline __attribute__((__noinline__))
// Avoid name mangling so that stacks are more readable.
@ -142,22 +155,36 @@ static int usage() {
fprintf(stderr, "where KIND is:\n");
fprintf(stderr, " smash-stack overwrite a -fstack-protector guard\n");
fprintf(stderr, " stack-overflow recurse until the stack overflows\n");
fprintf(stderr, " nostack crash with a NULL stack pointer\n");
fprintf(stderr, "\n");
fprintf(stderr, " heap-corruption cause a libc abort by corrupting the heap\n");
fprintf(stderr, " heap-usage cause a libc abort by abusing a heap function\n");
fprintf(stderr, " nostack crash with a NULL stack pointer\n");
fprintf(stderr, "\n");
fprintf(stderr, " abort call abort()\n");
fprintf(stderr, " assert call assert() without a function\n");
fprintf(stderr, " assert2 call assert() with a function\n");
fprintf(stderr, " exit call exit(1)\n");
fprintf(stderr, "\n");
fprintf(stderr, " fortify fail a _FORTIFY_SOURCE check\n");
fprintf(stderr, " seccomp fail a seccomp check\n");
#if defined(__arm__)
fprintf(stderr, " kuser_helper_version call kuser_helper_version\n");
fprintf(stderr, " kuser_get_tls call kuser_get_tls\n");
fprintf(stderr, " kuser_cmpxchg call kuser_cmpxchg\n");
fprintf(stderr, " kuser_memory_barrier call kuser_memory_barrier\n");
fprintf(stderr, " kuser_cmpxchg64 call kuser_cmpxchg64\n");
#endif
fprintf(stderr, "\n");
fprintf(stderr, " LOG_ALWAYS_FATAL call liblog LOG_ALWAYS_FATAL\n");
fprintf(stderr, " LOG_ALWAYS_FATAL_IF call liblog LOG_ALWAYS_FATAL_IF\n");
fprintf(stderr, " LOG-FATAL call libbase LOG(FATAL)\n");
fprintf(stderr, "\n");
fprintf(stderr, " SIGFPE cause a SIGFPE\n");
fprintf(stderr, " SIGSEGV cause a SIGSEGV at address 0x0 (synonym: crash)\n");
fprintf(stderr, " SIGSEGV-non-null cause a SIGSEGV at a non-zero address\n");
fprintf(stderr, " SIGSEGV-unmapped mmap/munmap a region of memory and then attempt to access it\n");
fprintf(stderr, " SIGTRAP cause a SIGTRAP\n");
fprintf(stderr, "\n");
fprintf(stderr, " fprintf-NULL pass a null pointer to fprintf\n");
fprintf(stderr, " readdir-NULL pass a null pointer to readdir\n");
fprintf(stderr, " strlen-NULL pass a null pointer to strlen\n");
@ -235,6 +262,20 @@ noinline int do_action(const char* arg) {
MAP_SHARED | MAP_ANONYMOUS, -1, 0));
munmap(map, sizeof(int));
map[0] = '8';
} else if (!strcasecmp(arg, "seccomp")) {
syscall(99999);
#if defined(__arm__)
} else if (!strcasecmp(arg, "kuser_helper_version")) {
return __kuser_helper_version;
} else if (!strcasecmp(arg, "kuser_get_tls")) {
return !__kuser_get_tls();
} else if (!strcasecmp(arg, "kuser_cmpxchg")) {
return __kuser_cmpxchg(0, 0, 0);
} else if (!strcasecmp(arg, "kuser_memory_barrier")) {
__kuser_dmb();
} else if (!strcasecmp(arg, "kuser_cmpxchg64")) {
return __kuser_cmpxchg64(0, 0, 0);
#endif
} else {
return usage();
}

48
debuggerd/libdebuggerd/tombstone.cpp
View file

@ -49,6 +49,8 @@
#include "open_files_list.h"
#include "tombstone.h"
using android::base::StringPrintf;
#define STACK_WORDS 16
#define MAX_TOMBSTONES 10
@ -74,7 +76,7 @@ static bool signal_has_si_addr(int si_signo, int si_code) {
}
static const char* get_signame(int sig) {
switch(sig) {
switch (sig) {
case SIGABRT: return "SIGABRT";
case SIGBUS: return "SIGBUS";
case SIGFPE: return "SIGFPE";
@ -195,6 +197,29 @@ static void dump_header_info(log_t* log) {
_LOG(log, logtype::HEADER, "ABI: '%s'\n", ABI_STRING);
}
static void dump_probable_cause(log_t* log, const siginfo_t& si) {
std::string cause;
if (si.si_signo == SIGSEGV && si.si_code == SEGV_MAPERR) {
if (si.si_addr < reinterpret_cast<void*>(4096)) {
cause = StringPrintf("null pointer dereference");
} else if (si.si_addr == reinterpret_cast<void*>(0xffff0ffc)) {
cause = "call to kuser_helper_version";
} else if (si.si_addr == reinterpret_cast<void*>(0xffff0fe0)) {
cause = "call to kuser_get_tls";
} else if (si.si_addr == reinterpret_cast<void*>(0xffff0fc0)) {
cause = "call to kuser_cmpxchg";
} else if (si.si_addr == reinterpret_cast<void*>(0xffff0fa0)) {
cause = "call to kuser_memory_barrier";
} else if (si.si_addr == reinterpret_cast<void*>(0xffff0f60)) {
cause = "call to kuser_cmpxchg64";
}
} else if (si.si_signo == SIGSYS && si.si_code == SYS_SECCOMP) {
cause = StringPrintf("seccomp prevented call to disallowed system call %d", si.si_syscall);
}
if (!cause.empty()) _LOG(log, logtype::HEADER, "Cause: %s\n", cause.c_str());
}
static void dump_signal_info(log_t* log, pid_t tid) {
siginfo_t si;
memset(&si, 0, sizeof(si));
@ -212,6 +237,8 @@ static void dump_signal_info(log_t* log, pid_t tid) {
_LOG(log, logtype::HEADER, "signal %d (%s), code %d (%s), fault addr %s\n", si.si_signo,
get_signame(si.si_signo), si.si_code, get_sigcode(si.si_signo, si.si_code), addr_desc);
dump_probable_cause(log, si);
}
static void dump_thread_info(log_t* log, pid_t pid, pid_t tid) {
@ -262,11 +289,11 @@ static void dump_stack_segment(
line = " ";
if (i == 0 && label >= 0) {
// Print the label once.
line += android::base::StringPrintf("#%02d ", label);
line += StringPrintf("#%02d ", label);
} else {
line += " ";
}
line += android::base::StringPrintf("%" PRIPTR " %" PRIPTR, *sp, stack_data[i]);
line += StringPrintf("%" PRIPTR " %" PRIPTR, *sp, stack_data[i]);
backtrace_map_t map;
backtrace->FillInMap(stack_data[i], &map);
@ -277,7 +304,7 @@ static void dump_stack_segment(
if (!func_name.empty()) {
line += " (" + func_name;
if (offset) {
line += android::base::StringPrintf("+%" PRIuPTR, offset);
line += StringPrintf("+%" PRIuPTR, offset);
}
line += ')';
}
@ -336,11 +363,11 @@ static void dump_stack(Backtrace* backtrace, log_t* log) {
static std::string get_addr_string(uintptr_t addr) {
std::string addr_str;
#if defined(__LP64__)
addr_str = android::base::StringPrintf("%08x'%08x",
static_cast<uint32_t>(addr >> 32),
static_cast<uint32_t>(addr & 0xffffffff));
addr_str = StringPrintf("%08x'%08x",
static_cast<uint32_t>(addr >> 32),
static_cast<uint32_t>(addr & 0xffffffff));
#else
addr_str = android::base::StringPrintf("%08x", addr);
addr_str = StringPrintf("%08x", addr);
#endif
return addr_str;
}
@ -426,8 +453,7 @@ static void dump_all_maps(Backtrace* backtrace, BacktraceMap* map, log_t* log, p
} else {
line += '-';
}
line += android::base::StringPrintf(" %8" PRIxPTR " %8" PRIxPTR,
it->offset, it->end - it->start);
line += StringPrintf(" %8" PRIxPTR " %8" PRIxPTR, it->offset, it->end - it->start);
bool space_needed = true;
if (it->name.length() > 0) {
space_needed = false;
@ -441,7 +467,7 @@ static void dump_all_maps(Backtrace* backtrace, BacktraceMap* map, log_t* log, p
if (space_needed) {
line += ' ';
}
line += android::base::StringPrintf(" (load base 0x%" PRIxPTR ")", it->load_base);
line += StringPrintf(" (load base 0x%" PRIxPTR ")", it->load_base);
}
_LOG(log, logtype::MAPS, "%s\n", line.c_str());
}