Add executable= argument to ELF.search (#1576)

* Add `executable=` argument like `writable=` to ELF.search

* Add doctest using ELF.search with `executable = True`

* Fix `__next__()` issue.

pwnlib/elf/elf.py

@@ -1115,8 +1115,8 @@ def libc_start_main_return(self):
         return_from_main = int(return_from_main[ : return_from_main.index(':') ], 16)
         return return_from_main
 
-    def search(self, needle, writable = False):
-        """search(needle, writable = False) -> generator
+    def search(self, needle, writable = False, executable = False):
+        """search(needle, writable = False, executable = False) -> generator
 
         Search the ELF's virtual address space for the specified string.
 
@@ -1129,6 +1129,7 @@ def search(self, needle, writable = False):
         Arguments:
             needle(str): String to search for.
             writable(bool): Search only writable sections.
+            executable(bool): Search only executable sections.
 
         Yields:
             An iterator for each virtual address that matches.
@@ -1146,11 +1147,20 @@ def search(self, needle, writable = False):
 
             >>> len(list(bash.search(b'GNU bash'))) > 0
             True
+
+            It is also possible to search for instructions in executable sections.
+
+            >>> binary = ELF.from_assembly('nop; mov eax, 0; jmp esp; ret')
+            >>> jmp_addr = next(binary.search(asm('jmp esp'), executable = True))
+            >>> binary.read(jmp_addr, 2) == asm('jmp esp')
+            True
         """
         load_address_fixup = (self.address - self.load_addr)
 
         if writable:
             segments = self.writable_segments
+        elif executable:
+            segments = self.executable_segments
         else:
             segments = self.segments