Messages in this thread | | | Date | Tue, 20 Apr 2004 11:09:19 +0200 | From | Zoltan Menyhart <> | Subject | Dynamic System Calls & System Call Hijacking - demo syscall |
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/* * Demo dynamic syscall */
#include <linux/module.h> #include <asm/dyn_syscall.h>
const char name[] = "foo";
asmlinkage long sys_foo(const int cmd, const caddr_t address, const size_t length, const int node, const pid_t pid) { printk("\nsys_foo(%d, 0x%p, 0x%lx, %d, %d)\n", cmd, address, length, node, pid); return 0; }
int syscall;
static int __init init_foo(void) { int rc;
printk("\nModule Foo\n"); rc = dyn_syscall_reg(name, 0, (dyn_syscall_t) sys_foo); printk("dyn_syscall_reg() returned: %d\n", rc); if (rc < 0) return rc; syscall = rc; rc = syscall_unlock(name, syscall); if (rc < 0) panic("syscall_unlock() returned: %d\n", rc); return 0; }
static void __exit exit_foo(void) { printk("\nModule Foo getting unloaded\n"); int rc; rc = prep_restore_syscall(name, syscall); if (rc < 0) panic("prep_restore_syscall() returned: %d\n", rc); while((rc = syscall_trylock(name, syscall)) == -EAGAIN){ /* * Having some blocking syscalls? Don't just busy wait, * wake them up, sleep a bit in the mean time. */ } if (rc < 0) panic("syscall_trylock() returned: %d\n", rc); rc = dyn_syscall_unreg(name, syscall); if (rc < 0) panic("dyn_syscall_unreg() returned: %d\n", rc); }
module_init(init_foo); module_exit(exit_foo);
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