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#include <Python.h>
#include <stdio.h> //remove when you remove printf
#include <string.h>
#include <gelf.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#define HF_PAX_PAGEEXEC 1
#define HF_PAX_EMUTRAMP 2
#define HF_PAX_MPROTECT 4
#define HF_PAX_RANDMMAP 8
#define HF_PAX_RANDEXEC 16
#define HF_PAX_SEGMEXEC 32
#define EI_PAX 14 // Index to read the PaX flags into ELF header e_ident[] array
#define BUF_SIZE 7 //Buffer for holding human readable flags
static PyObject * pax_getflags(PyObject *, PyObject *);
static PyMethodDef PaxMethods[] = {
{"getflags", pax_getflags, METH_VARARGS, "Get the pax flags."},
{NULL, NULL, 0, NULL}
};
static PyObject *PaxError;
PyMODINIT_FUNC
initpax(void)
{
PyObject *m;
m = Py_InitModule("pax", PaxMethods);
if (m == NULL)
return;
PaxError = PyErr_NewException("pax.error", NULL, NULL);
Py_INCREF(PaxError);
PyModule_AddObject(m, "error", PaxError);
}
static PyObject *
pax_getflags(PyObject *self, PyObject *args)
{
const char *f_name;
int fd, sts;
Elf *elf;
char pax_buf[BUF_SIZE];
GElf_Ehdr ehdr;
uint16_t ei_flags;
GElf_Phdr phdr;
char found_pt_pax;
size_t i, phnum;
memset(pax_buf, 0, BUF_SIZE);
if (!PyArg_ParseTuple(args, "s", &f_name))
{
PyErr_SetString(PaxError, "pax_getflags: PyArg_ParseTuple failed");
return NULL;
}
if(elf_version(EV_CURRENT) == EV_NONE)
{
PyErr_SetString(PaxError, "pax_getflags: library out of date");
return NULL;
}
if((fd = open(f_name, O_RDONLY)) < 0)
{
PyErr_SetString(PaxError, "pax_getflags: open() failed");
return NULL;
}
if((elf = elf_begin(fd, ELF_C_READ_MMAP, NULL)) == NULL)
{
close(fd);
PyErr_SetString(PaxError, "pax_getflags: elf_begin() failed");
return NULL;
}
if(elf_kind(elf) != ELF_K_ELF)
{
elf_end(elf);
close(fd);
PyErr_SetString(PaxError, "pax_getflags: elf_kind() failed: this is not an elf file.");
return NULL;
}
found_pt_pax = 0;
elf_getphdrnum(elf, &phnum);
for(i=0; i<phnum; ++i)
{
if(gelf_getphdr(elf, i, &phdr) != &phdr)
{
elf_end(elf);
close(fd);
PyErr_SetString(PaxError, "pax_getflags: gelf_getphdr() failed");
return NULL;
}
if(phdr.p_type == PT_PAX_FLAGS)
{
found_pt_pax = 1;
pax_buf[0] = phdr.p_flags & PF_PAGEEXEC ? 'P' :
phdr.p_flags & PF_NOPAGEEXEC ? 'p' : '-' ;
pax_buf[1] = phdr.p_flags & PF_SEGMEXEC ? 'S' :
phdr.p_flags & PF_NOSEGMEXEC ? 's' : '-';
pax_buf[2] = phdr.p_flags & PF_MPROTECT ? 'M' :
phdr.p_flags & PF_NOMPROTECT ? 'm' : '-';
pax_buf[3] = phdr.p_flags & PF_EMUTRAMP ? 'E' :
phdr.p_flags & PF_NOEMUTRAMP ? 'e' : '-';
pax_buf[4] = phdr.p_flags & PF_RANDMMAP ? 'R' :
phdr.p_flags & PF_NORANDMMAP ? 'r' : '-';
pax_buf[5] = phdr.p_flags & PF_RANDEXEC ? 'X' :
phdr.p_flags & PF_NORANDEXEC ? 'x' : '-';
}
}
if(!found_pt_pax)
{
if(gelf_getehdr(elf, &ehdr) != &ehdr)
{
elf_end(elf);
close(fd);
PyErr_SetString(PaxError, "pax_getflags: gelf_getehdr() failed");
return NULL;
}
ei_flags = ehdr.e_ident[EI_PAX] + (ehdr.e_ident[EI_PAX + 1] << 8);
pax_buf[0] = ei_flags & HF_PAX_PAGEEXEC ? 'p' : 'P';
pax_buf[1] = ei_flags & HF_PAX_SEGMEXEC ? 's' : 'S';
pax_buf[2] = ei_flags & HF_PAX_MPROTECT ? 'm' : 'M';
pax_buf[3] = ei_flags & HF_PAX_EMUTRAMP ? 'E' : 'e';
pax_buf[4] = ei_flags & HF_PAX_RANDMMAP ? 'r' : 'R';
pax_buf[5] = ei_flags & HF_PAX_RANDEXEC ? 'X' : 'x';
}
elf_end(elf);
close(fd);
return Py_BuildValue("s", pax_buf);
}
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