mprotect

Hi I'm trying to load raw machine code into memory and run it from within a C program, right now when the program executes it breaks when trying to run mprotect on the memory to make it executable. I'm also not entirely sure that if the memory does get set right it will execute. I am currently running this on Ubuntu Linux x86 (Maybe the problem is Ubuntu's over-protection?) What I currently have is the following: #include <memory.h> #include <sys/mman.h> #include <stdio.h> int main ( int argc, char **argv ) { FILE *fp; int sz = 0; char *membuf; int output = 0; fp = fopen(argv[1],"rb"); if(fp =

I'm writing an iPhone application using Monotouch and recently the app has started crashing stating Mprotect failed at 0x863a000 (length 8192) with errno 12 followed by a rather lengthly stack trace and Springboard informing that "the application exited abormally with signal 6". I've read this question which states that the app has exhaused all the memory available on the iPhone. We have applied some general Dispose patterns to the app and generally disposed of any heavy objects as soon as we could. This meant the app now runs using less memory. However we are still getting the MProtect failed

I'm constructing a program which uses mprotect() to restrict a block of memory from accessing. When the memory is requested, a SIGSEGV is thrown which I listen for using a signal() call. Once the SIGSEGV has been detected, I need to somehow access the pointer to the memory that was requested (that threw the fault) and the size of the segment requested. Is this possible? void fifoSigHandler(){ // Needs to only remove protection from requested block of virtual memory mprotect(fifoVm,(size_t)fifoVm_size,PROT_WRITE); printf("Caught Seg Fault"); } void fifo_init(void* vm, int vm_size, int n_frames,

I've been trying to use mprotect against reading first, and then writing. Is here my code #include <sys/types.h> #include <sys/mman.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> int main(void) { int pagesize = sysconf(_SC_PAGE_SIZE); int *a; if (posix_memalign((void**)&a, pagesize, sizeof(int)) != 0) perror("memalign"); *a = 42; if (mprotect(a, pagesize, PROT_WRITE) == -1) /* Resp. PROT_READ */ perror("mprotect"); printf("a = %d\n", *a); *a = 24; printf("a = %d\n", *a); free (a); return 0; } Under Linux here are the results: Here is the output for PROT_WRITE : $ ./main a = 42 a

I have a problem with my iPhone application developed with MonoTouch. I am developing an application that contacts a WCF Service, and when the WCF Service answer back, I update an UITableView with the returned data, when this is done it sends a new WCF async call, and when it answer back it updates the table again and so on. The problem is that when it has done this in a variable amount of time, it crashes with an Mprotect failed error 12. This only happens when the application is running directly on the phone and not in the simulator. I have tried to out comment where the update of the table

On Linux (or Solaris) is there a better way than hand parsing /proc/self/maps repeatedly to figure out whether or not you can read, write or execute whatever is stored at one or more addresses in memory? For instance, in Windows you have VirtualQuery . In Linux, I can mprotect to change those values, but I can't read them back. Furthermore, is there any way to know when those permissions change (e.g. when someone uses mmap on a file behind my back) other than doing something terribly invasive and using ptrace on all threads in the process and intercepting any attempt to make a syscall that