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am 17361134: Merge "Add a "smash-stack" option to crasher."

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# Via Elliott Hughes (1) and Gerrit Code Review (1)
* commit '17361134180b178531979897f9c9867346a57f10':
  Add a "smash-stack" option to crasher.
This commit is contained in:
Elliott Hughes 2013-02-14 16:16:26 -08:00 • committed by Android Git Automerger
commit 910b7a8b88
2 changed files with 14 additions and 0 deletions
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1
debuggerd/Android.mk
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@ -37,6 +37,7 @@ LOCAL_SRC_FILES += $(TARGET_ARCH)/crashglue.S
LOCAL_MODULE := crasher
LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES)
LOCAL_MODULE_TAGS := optional
LOCAL_CFLAGS += -fstack-protector-all
#LOCAL_FORCE_STATIC_EXECUTABLE := true
LOCAL_SHARED_LIBRARIES := libcutils libc
include $(BUILD_EXECUTABLE)

13
debuggerd/crasher.c
View file

@ -35,6 +35,18 @@ static void debuggerd_connect()
}
}
int smash_stack(int i) {
printf("crasher: deliberately corrupting stack...\n");
// Unless there's a "big enough" buffer on the stack, gcc
// doesn't bother inserting checks.
char buf[8];
// If we don't write something relatively unpredicatable
// into the buffer and then do something with it, gcc
// optimizes everything away and just returns a constant.
*(int*)(&buf[7]) = (uintptr_t) &buf[0];
return *(int*)(&buf[0]);
}
void test_call1()
{
*((int*) 32) = 1;
@ -95,6 +107,7 @@ int do_action(const char* arg)
return do_action_on_thread(arg + strlen("thread-"));
}
if(!strcmp(arg,"smash-stack")) return smash_stack(42);
if(!strcmp(arg,"nostack")) crashnostack();
if(!strcmp(arg,"ctest")) return ctest();
if(!strcmp(arg,"exit")) exit(1);