libctf: add the object index and function index sections

No code handles these yet, but our latest GCC patches are generating
them, so we have to be ready for them or erroneously conclude that we
have file corruption.

(This simultaneously fixes a longstanding bug, concealed because nothing
was generating anything in the object or function info sections, where
the end of the section was being tested against the wrong thing: it
would have walked over the entire contents of the variable section and
treated them as part of the function info section.  This had to change
now anyway because the new sections have landed in between.)

include/
	* ctf.h: Add object index and function index sections.  Describe
	them. Improve the description of the variable section and clarify
	the constraints on backward-pointing type nodes.
	(ctf_header): Add cth_objtidxoff, cth_funcidxoff.

libctf/
	* ctf-open.c (init_symtab): Check for overflow against the right
	section.
	(upgrade_header): Set cth_objtidxoff, cth_funcidxoff to zero-length.
	(upgrade_types_v1): Note that these sections are not checked.
	(flip_header): Endian-swap the header fields.
	(flip_ctf): Endian-swap the sections.
	(flip_objts): Update comment.
	(ctf_bufopen): Check header offsets and alignment for validity.

2 files changed, 33 insertions, 9 deletions

diff --git a/libctf/ChangeLog b/libctf/ChangeLog
index 7fa9fc0..64d644f 100644
--- a/libctf/ChangeLog
+++ b/libctf/ChangeLog
@@ -1,5 +1,16 @@
 2019-07-13  Nick Alcock  <nick.alcock@oracle.com>
 
+	* ctf-open.c (init_symtab): Check for overflow against the right
+	section.
+	(upgrade_header): Set cth_objtidxoff, cth_funcidxoff to zero-length.
+	(upgrade_types_v1): Note that these sections are not checked.
+	(flip_header): Endian-swap the header fields.
+	(flip_ctf): Endian-swap the sections.
+	(flip_objts): Update comment.
+	(ctf_bufopen): Check header offsets and alignment for validity.
+
+2019-07-13  Nick Alcock  <nick.alcock@oracle.com>
+
 	* ctf-open-bfd.c: Add <assert.h>.
 	(ctf_bfdopen_ctfsect): Open string and symbol tables using
 	techniques borrowed from bfd_elf_sym_name.
diff --git a/libctf/ctf-open.c b/libctf/ctf-open.c
index 51f9edc..c96bad7 100644
--- a/libctf/ctf-open.c
+++ b/libctf/ctf-open.c
@@ -278,7 +278,7 @@ init_symtab (ctf_file_t *fp, const ctf_header_t *hp,
 	  break;
 
 	case STT_FUNC:
-	  if (funcoff >= hp->cth_typeoff)
+	  if (funcoff >= hp->cth_objtidxoff)
 	    {
 	      *xp = -1u;
 	      break;
@@ -376,6 +376,8 @@ upgrade_header (ctf_header_t *hp)
   hp->cth_stroff = oldhp->cth_stroff;
   hp->cth_typeoff = oldhp->cth_typeoff;
   hp->cth_varoff = oldhp->cth_varoff;
+  hp->cth_funcidxoff = hp->cth_varoff;		/* No index sections.  */
+  hp->cth_objtidxoff = hp->cth_funcidxoff;
   hp->cth_funcoff = oldhp->cth_funcoff;
   hp->cth_objtoff = oldhp->cth_objtoff;
   hp->cth_lbloff = oldhp->cth_lbloff;
@@ -388,6 +390,9 @@ upgrade_header (ctf_header_t *hp)
    The upgrade is not done in-place: the ctf_base is moved.  ctf_strptr() must
    not be called before reallocation is complete.
 
+   Sections not checked here due to nonexistence or nonpopulated state in older
+   formats: objtidx, funcidx.
+
    Type kinds not checked here due to nonexistence in older formats:
       CTF_K_SLICE.  */
 static int
@@ -967,6 +972,8 @@ flip_header (ctf_header_t *cth)
   swap_thing (cth->cth_cuname);
   swap_thing (cth->cth_objtoff);
   swap_thing (cth->cth_funcoff);
+  swap_thing (cth->cth_objtidxoff);
+  swap_thing (cth->cth_funcidxoff);
   swap_thing (cth->cth_varoff);
   swap_thing (cth->cth_typeoff);
   swap_thing (cth->cth_stroff);
@@ -987,10 +994,10 @@ flip_lbls (void *start, size_t len)
     }
 }
 
-/* Flip the endianness of the data-object or function sections, an array of
-   uint32_t.  (The function section has more internal structure, but that
-   structure is an array of uint32_t, so can be treated as one big array for
-   byte-swapping.)  */
+/* Flip the endianness of the data-object or function sections or their indexes,
+   all arrays of uint32_t.  (The function section has more internal structure,
+   but that structure is an array of uint32_t, so can be treated as one big
+   array for byte-swapping.)  */
 
 static void
 flip_objts (void *start, size_t len)
@@ -1176,7 +1183,9 @@ flip_ctf (ctf_header_t *cth, unsigned char *buf)
 {
   flip_lbls (buf + cth->cth_lbloff, cth->cth_objtoff - cth->cth_lbloff);
   flip_objts (buf + cth->cth_objtoff, cth->cth_funcoff - cth->cth_objtoff);
-  flip_objts (buf + cth->cth_funcoff, cth->cth_varoff - cth->cth_funcoff);
+  flip_objts (buf + cth->cth_funcoff, cth->cth_objtidxoff - cth->cth_funcoff);
+  flip_objts (buf + cth->cth_objtidxoff, cth->cth_funcidxoff - cth->cth_objtidxoff);
+  flip_objts (buf + cth->cth_funcidxoff, cth->cth_varoff - cth->cth_funcidxoff);
   flip_vars (buf + cth->cth_varoff, cth->cth_typeoff - cth->cth_varoff);
   return flip_types (buf + cth->cth_typeoff, cth->cth_stroff - cth->cth_typeoff);
 }
@@ -1330,19 +1339,23 @@ ctf_bufopen (const ctf_sect_t *ctfsect, const ctf_sect_t *symsect,
 	       (unsigned long) fp->ctf_size);
 
   if (hp->cth_lbloff > fp->ctf_size || hp->cth_objtoff > fp->ctf_size
-      || hp->cth_funcoff > fp->ctf_size || hp->cth_typeoff > fp->ctf_size
+      || hp->cth_funcoff > fp->ctf_size || hp->cth_objtidxoff > fp->ctf_size
+      || hp->cth_funcidxoff > fp->ctf_size || hp->cth_typeoff > fp->ctf_size
       || hp->cth_stroff > fp->ctf_size)
     return (ctf_set_open_errno (errp, ECTF_CORRUPT));
 
   if (hp->cth_lbloff > hp->cth_objtoff
       || hp->cth_objtoff > hp->cth_funcoff
       || hp->cth_funcoff > hp->cth_typeoff
-      || hp->cth_funcoff > hp->cth_varoff
+      || hp->cth_funcoff > hp->cth_objtidxoff
+      || hp->cth_objtidxoff > hp->cth_funcidxoff
+      || hp->cth_funcidxoff > hp->cth_varoff
       || hp->cth_varoff > hp->cth_typeoff || hp->cth_typeoff > hp->cth_stroff)
     return (ctf_set_open_errno (errp, ECTF_CORRUPT));
 
   if ((hp->cth_lbloff & 3) || (hp->cth_objtoff & 2)
-      || (hp->cth_funcoff & 2) || (hp->cth_varoff & 3)
+      || (hp->cth_funcoff & 2) || (hp->cth_objtidxoff & 2)
+      || (hp->cth_funcidxoff & 2) || (hp->cth_varoff & 3)
       || (hp->cth_typeoff & 3))
     return (ctf_set_open_errno (errp, ECTF_CORRUPT));