added elf_executable_text_filesz to header file

examples/Makefile

@@ -33,6 +33,7 @@ all:
 	$(CC) -Wl,-z,separate-code test.c -o test_scop_pie
 	$(CC) -no-pie -Wl,-z,separate-code test.c -o test_scop_binary
 	$(CC) -O2 -g pltgot.c -o pltgot ../src/libelfmaster.a
+	$(CC) -O2 -g scop_check.c -o scop_check ../src/libelfmaster.a
 	$(CC) phoff.c -o phoff ../src/libelfmaster.a
 	./stripx test_stripped
 	./stripx test32_stripped

include/libelfmaster.h

@@ -866,7 +866,7 @@ bool elf_write_address(elfobj_t *, uint64_t, uint64_t, typewidth_t width);
 size_t __attribute__((deprecated)) elf_scop_text_filesz(elfobj_t *);
 uint64_t elf_executable_text_offset(elfobj_t *);
 uint64_t elf_executable_text_base(elfobj_t *);
-
+uint64_t elf_executable_text_filesz(elfobj_t *);
 /*
  * 2nd arg is an output of the number of entries in .symtab
  * returns true on success. Same thing for elf_dynsym_count

src/libelfmaster.c

@@ -1041,6 +1041,18 @@ elf_executable_text_filesz(struct elfobj *obj)
 					 */
 					struct elf_section section;
 
+					/*
+					 * If the segment address segment.vaddr is within
+					 * the range of an ELF section who is also claiming
+					 * it has executable perms, then we can avoid finding
+					 * a segment that was marked executable by an attacker
+					 * and assume the linker made the right choice in marking
+					 * the section as executable progbits.
+					 *
+					 * ON THE FLIP SIDE: If an attacker were to modify the
+					 * perm flags of the section that our address resides in...
+					 * well we might not find the right segment.
+					 */
                                         if (elf_section_by_address(obj, segment.vaddr,
                                             &section) == true) {
                                                 if (section.flags & SHF_EXECINSTR)