Xorl %eax, %eax make sure that noone can read the random value afterwards Movl %eax, 12(%esp) store value as a guard variable The following is the (simplified and commented) smash.S file:
#Stack smashing detected how does it work code
Lets look at the code which is generated by the compiler: When we compile and run this application, we will get a runtime error: Lets take a closer look at gs:0x10 which I mentioned above: The stack_guard member contains a random value which is used to protect against stack smashing – consider the following sample which contains an obvious buffer overflow: Void *_private_ss /* gs:0x34 GCC split stack support. Void *_private_tm /* gs:0x24 Reservation of some values for the TM ABI. Uintptr_t pointer_guard /* gs:0x18 Random value used for pointer protection */ Uintptr_t stack_guard /* gs:0x14 Random value used for stack protection */ Uintptr_t sysinfo /* gs:0x10 Syscall interface */ Void *self /* gs:0x08 Pointer to the thread descriptor. The Thread Control Block header is a structure which is defined in the C library, for example in eglibc-2.19/nptl/sysdeps/i386/tls.h (slightly simplified and added the gs segment offsets): Here, gs refers to the Thread Control Block (TCB) header which stores per-CPU and thread local data (Thread Local Storage, TLS). When disassembling (32 bit i386 / x86) code on Linux, we sometimes come across instructions like Wrapping a Java Bean into a Data Control.Using database links in the Oracle RDBMS.Setting up the Application Server: JBoss.
Setting up the Application Server: WebLogic.Setting up the Application Server: Tomcat.Installing the required Eclipse plugins.Setting up a web development environment with Eclipse.Code which implements the custom EL resolver.Implementing a custom EL resolver in ADF.Manually adding the Method Call Activity.Adding a Method Call Activitiy to an ADF task flow.Overview of Oracle Platform Security Services.Introduction into functional programming.Hierarchical queries using the Oracle RDBMS.JDK’s bin directory – Command line monitoring tools.JDK’s bin directory – GUI monitoring tools.JDK’s bin directory – general development tools.Electronic circuit simulation with NG-SPICE.Configuring Linux with initial ramdisk support.
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