From b5796c9a30c81c35b9849094344f86d60a16e2c2 Mon Sep 17 00:00:00 2001
From: Aleksandar Ristovski <ARistovski@qnx.com>
Date: Wed, 27 Mar 2013 16:05:19 -0400
Subject: [PATCH 7/8] Validate symbol file using build-id.

	* solib-darwin.c (_initialize_darwin_solib): Assign validate value.
	* solib-dsbt.c (_initialize_dsbt_solib): Ditto.
	* solib-frv.c (_initialize_frv_solib): Ditto.
	* solib-ia64-hpux.c (ia64_hpux_target_so_ops): Ditto.
	* solib-irix.c (_initialize_irix_solib): Ditto.
	* solib-osf.c (_initialize_osf_solib): Ditto.
	* solib-pa64.c (_initialize_pa64_solib): Ditto.
	* solib-som.c (_initialize_som_solib): Ditto.
	* solib-spu.c (set_spu_solib_ops): Ditto.
	* solib-sunos.c (_initialize_sunos_solib): Ditto.
	* solib-svr4.c (svr4_validate): New function.
	(library_list_start_library): Parse 'build-id' attribute.
	(svr4_library_attributes): Add 'build-id' attribute.
	(svr4_relocate_section_addresses): Read build-id from target
	memory.
	(_initialize_svr4_solib): Assign validate value.
	* solib-svr4.h (DYNAMIC_NAME): New define.
	(NOTE_GNU_BUILD_ID_NAME): New define.
	* solib-target.c (solib.h): Include.
	(_initialize_solib_target): Assign validate value.
	* solib.c (solib_map_sections): Use ops->validate.
	(free_so): Free build_id.
	(solib_validate): New function.
	* solib.h (solib_validate): New declaration.
	* solist.h (so_list): New fields 'build_idsz' and 'build_id'.
	(target_so_ops): New field 'validate'.
---
 gdb/solib-darwin.c    |    1 +
 gdb/solib-dsbt.c      |    1 +
 gdb/solib-frv.c       |    1 +
 gdb/solib-ia64-hpux.c |    1 +
 gdb/solib-irix.c      |    1 +
 gdb/solib-osf.c       |    1 +
 gdb/solib-pa64.c      |    1 +
 gdb/solib-som.c       |    1 +
 gdb/solib-spu.c       |    1 +
 gdb/solib-sunos.c     |    1 +
 gdb/solib-svr4.c      |   91 +++++++++++++++++++++++++++++++++++++++++++++++++
 gdb/solib-svr4.h      |    3 ++
 gdb/solib-target.c    |    2 ++
 gdb/solib.c           |   20 +++++++++++
 gdb/solib.h           |    4 +++
 gdb/solist.h          |   14 ++++++++
 16 files changed, 144 insertions(+)

diff --git a/gdb/solib-darwin.c b/gdb/solib-darwin.c
index b9a4be1..ff57016 100644
--- a/gdb/solib-darwin.c
+++ b/gdb/solib-darwin.c
@@ -647,4 +647,5 @@ _initialize_darwin_solib (void)
   darwin_so_ops.in_dynsym_resolve_code = darwin_in_dynsym_resolve_code;
   darwin_so_ops.lookup_lib_global_symbol = darwin_lookup_lib_symbol;
   darwin_so_ops.bfd_open = darwin_bfd_open;
+  darwin_so_ops.validate = default_solib_validate;
 }
diff --git a/gdb/solib-dsbt.c b/gdb/solib-dsbt.c
index ea2acd1..9728470 100644
--- a/gdb/solib-dsbt.c
+++ b/gdb/solib-dsbt.c
@@ -1182,6 +1182,7 @@ _initialize_dsbt_solib (void)
   dsbt_so_ops.open_symbol_file_object = open_symbol_file_object;
   dsbt_so_ops.in_dynsym_resolve_code = dsbt_in_dynsym_resolve_code;
   dsbt_so_ops.bfd_open = solib_bfd_open;
+  dsbt_so_ops.validate = default_solib_validate;
 
   /* Debug this file's internals.  */
   add_setshow_zuinteger_cmd ("solib-dsbt", class_maintenance,
diff --git a/gdb/solib-frv.c b/gdb/solib-frv.c
index 57e418f..5621b2a 100644
--- a/gdb/solib-frv.c
+++ b/gdb/solib-frv.c
@@ -1182,6 +1182,7 @@ _initialize_frv_solib (void)
   frv_so_ops.open_symbol_file_object = open_symbol_file_object;
   frv_so_ops.in_dynsym_resolve_code = frv_in_dynsym_resolve_code;
   frv_so_ops.bfd_open = solib_bfd_open;
+  frv_so_ops.validate = default_solib_validate;
 
   /* Debug this file's internals.  */
   add_setshow_zuinteger_cmd ("solib-frv", class_maintenance,
diff --git a/gdb/solib-ia64-hpux.c b/gdb/solib-ia64-hpux.c
index 67085d7..6fb146c 100644
--- a/gdb/solib-ia64-hpux.c
+++ b/gdb/solib-ia64-hpux.c
@@ -686,6 +686,7 @@ ia64_hpux_target_so_ops (void)
   ops->open_symbol_file_object = ia64_hpux_open_symbol_file_object;
   ops->in_dynsym_resolve_code = ia64_hpux_in_dynsym_resolve_code;
   ops->bfd_open = solib_bfd_open;
+  ops->validate = default_solib_validate;
 
   return ops;
 }
diff --git a/gdb/solib-irix.c b/gdb/solib-irix.c
index af3e7d6..871fb19 100644
--- a/gdb/solib-irix.c
+++ b/gdb/solib-irix.c
@@ -652,4 +652,5 @@ _initialize_irix_solib (void)
   irix_so_ops.open_symbol_file_object = irix_open_symbol_file_object;
   irix_so_ops.in_dynsym_resolve_code = irix_in_dynsym_resolve_code;
   irix_so_ops.bfd_open = solib_bfd_open;
+  irix_so_ops.validate = default_solib_validate;
 }
diff --git a/gdb/solib-osf.c b/gdb/solib-osf.c
index d05c5c1..5b1cd0b 100644
--- a/gdb/solib-osf.c
+++ b/gdb/solib-osf.c
@@ -633,6 +633,7 @@ _initialize_osf_solib (void)
   osf_so_ops.open_symbol_file_object = osf_open_symbol_file_object;
   osf_so_ops.in_dynsym_resolve_code = osf_in_dynsym_resolve_code;
   osf_so_ops.bfd_open = solib_bfd_open;
+  osf_so_ops.validate = default_solib_validate;
 
   /* FIXME: Don't do this here.  *_gdbarch_init() should set so_ops.  */
   current_target_so_ops = &osf_so_ops;
diff --git a/gdb/solib-pa64.c b/gdb/solib-pa64.c
index f646cfb..795bcda 100644
--- a/gdb/solib-pa64.c
+++ b/gdb/solib-pa64.c
@@ -621,6 +621,7 @@ _initialize_pa64_solib (void)
   pa64_so_ops.open_symbol_file_object = pa64_open_symbol_file_object;
   pa64_so_ops.in_dynsym_resolve_code = pa64_in_dynsym_resolve_code;
   pa64_so_ops.bfd_open = solib_bfd_open;
+  pa64_so_ops.validate = default_solib_validate;
 
   memset (&dld_cache, 0, sizeof (dld_cache));
 }
diff --git a/gdb/solib-som.c b/gdb/solib-som.c
index ff7fbaa..cc2d344 100644
--- a/gdb/solib-som.c
+++ b/gdb/solib-som.c
@@ -811,6 +811,7 @@ _initialize_som_solib (void)
   som_so_ops.open_symbol_file_object = som_open_symbol_file_object;
   som_so_ops.in_dynsym_resolve_code = som_in_dynsym_resolve_code;
   som_so_ops.bfd_open = solib_bfd_open;
+  som_so_ops.validate = default_solib_validate;
 }
 
 void
diff --git a/gdb/solib-spu.c b/gdb/solib-spu.c
index 7be5232..4cc343b 100644
--- a/gdb/solib-spu.c
+++ b/gdb/solib-spu.c
@@ -519,6 +519,7 @@ set_spu_solib_ops (struct gdbarch *gdbarch)
       spu_so_ops.current_sos = spu_current_sos;
       spu_so_ops.bfd_open = spu_bfd_open;
       spu_so_ops.lookup_lib_global_symbol = spu_lookup_lib_symbol;
+      spu_so_ops.validate = default_solib_validate;
     }
 
   set_solib_ops (gdbarch, &spu_so_ops);
diff --git a/gdb/solib-sunos.c b/gdb/solib-sunos.c
index 5863fc2..71c8ee3 100644
--- a/gdb/solib-sunos.c
+++ b/gdb/solib-sunos.c
@@ -738,6 +738,7 @@ _initialize_sunos_solib (void)
   sunos_so_ops.open_symbol_file_object = open_symbol_file_object;
   sunos_so_ops.in_dynsym_resolve_code = sunos_in_dynsym_resolve_code;
   sunos_so_ops.bfd_open = solib_bfd_open;
+  sunos_so_ops.validate = default_solib_validate;
 
   /* FIXME: Don't do this here.  *_gdbarch_init() should set so_ops.  */
   current_target_so_ops = &sunos_so_ops;
diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
index 601e34d..023927a 100644
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@@ -871,6 +871,29 @@ svr4_keep_data_in_core (CORE_ADDR vaddr, unsigned long size)
   return (name_lm >= vaddr && name_lm < vaddr + size);
 }
 
+/* Validate SO by comparing build-id from the associated bfd and
+   corresponding build-id from target memory.  */
+
+static int
+svr4_validate (const struct so_list *const so)
+{
+  gdb_assert (so != NULL);
+
+  if (so->abfd == NULL)
+    return 1;
+
+  if (!bfd_check_format (so->abfd, bfd_object)
+      || bfd_get_flavour (so->abfd) != bfd_target_elf_flavour
+      || elf_tdata (so->abfd)->build_id == NULL)
+    return 1;
+
+  if (so->build_id != NULL)
+    return elf_tdata (so->abfd)->build_id->size == so->build_idsz
+	   && memcmp (so->build_id, elf_tdata (so->abfd)->build_id->data,
+		      elf_tdata (so->abfd)->build_id->size) == 0;
+  return 1;
+}
+
 /* Implement the "open_symbol_file_object" target_so_ops method.
 
    If no open symbol file, attempt to locate and open the main symbol
@@ -999,6 +1022,9 @@ library_list_start_library (struct gdb_xml_parser *parser,
   ULONGEST *lmp = xml_find_attribute (attributes, "lm")->value;
   ULONGEST *l_addrp = xml_find_attribute (attributes, "l_addr")->value;
   ULONGEST *l_ldp = xml_find_attribute (attributes, "l_ld")->value;
+  const struct gdb_xml_value *const att_build_id
+    = xml_find_attribute (attributes, "build-id");
+  const char *const hex_build_id = att_build_id ? att_build_id->value : NULL;
   struct so_list *new_elem;
 
   new_elem = XZALLOC (struct so_list);
@@ -1010,6 +1036,26 @@ library_list_start_library (struct gdb_xml_parser *parser,
   strncpy (new_elem->so_name, name, sizeof (new_elem->so_name) - 1);
   new_elem->so_name[sizeof (new_elem->so_name) - 1] = 0;
   strcpy (new_elem->so_original_name, new_elem->so_name);
+  if (hex_build_id != NULL)
+    {
+      const size_t hex_build_id_len = strlen (hex_build_id); 
+
+      if (hex_build_id_len > 0)
+	{
+	  new_elem->build_id = xmalloc (hex_build_id_len / 2);
+	  new_elem->build_idsz = hex2bin (hex_build_id, new_elem->build_id,
+					  hex_build_id_len);
+	  if (new_elem->build_idsz != (hex_build_id_len / 2))
+	    {
+	      warning (_("Gdbserver returned invalid hex encoded build_id '%s'"
+			 "(%zu/%zu)\n"),
+		       hex_build_id, hex_build_id_len, new_elem->build_idsz);
+	      xfree (new_elem->build_id);
+	      new_elem->build_id = NULL;
+	      new_elem->build_idsz = 0;
+	    }
+	}
+    }
 
   *list->tailp = new_elem;
   list->tailp = &new_elem->next;
@@ -1044,6 +1090,7 @@ static const struct gdb_xml_attribute svr4_library_attributes[] =
   { "lm", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
   { "l_addr", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
   { "l_ld", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
+  { "build-id", GDB_XML_AF_NONE, NULL, NULL }, 
   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 };
 
@@ -2274,10 +2321,53 @@ static void
 svr4_relocate_section_addresses (struct so_list *so,
                                  struct target_section *sec)
 {
+  ULONGEST bfd_sect_size;
+
   sec->addr    = svr4_truncate_ptr (sec->addr    + lm_addr_check (so,
 								  sec->bfd));
   sec->endaddr = svr4_truncate_ptr (sec->endaddr + lm_addr_check (so,
 								  sec->bfd));
+
+  if (so->build_id == NULL)
+    {
+      /* Get build_id from NOTE_GNU_BUILD_ID_NAME section.  */
+      bfd_sect_size = bfd_get_section_size (sec->the_bfd_section);
+
+      if ((sec->the_bfd_section->flags & SEC_LOAD) == SEC_LOAD
+	  && bfd_sect_size != 0
+	  && strcmp (bfd_section_name (sec->bfd, sec->the_bfd_section),
+		     NOTE_GNU_BUILD_ID_NAME) == 0)
+	{
+	  CORE_ADDR build_id_offs;
+	  const enum bfd_endian byte_order
+	    = gdbarch_byte_order (target_gdbarch ());
+	  gdb_byte *const note_raw = xmalloc (bfd_sect_size);
+	  const Elf_External_Note *const note = (void *) note_raw;
+
+	  if (target_read_memory (sec->addr, note_raw, bfd_sect_size) == 0)
+	    {
+	      const ULONGEST descsz
+		= extract_unsigned_integer ((gdb_byte *) note->descsz, 4,
+					    byte_order);
+	      ULONGEST namesz;
+
+	      namesz = extract_unsigned_integer ((gdb_byte *) note->namesz, 4,
+						 byte_order);
+	      if (descsz == elf_tdata (so->abfd)->build_id->size)
+		{
+		  /* Rounded to next sizeof (ElfXX_Word) which happens
+		     to be 4 for both Elf32 and Elf64.  */
+		  namesz = (namesz + 3) & ~((ULONGEST) 3);
+		  build_id_offs = sizeof (note->namesz) + sizeof (note->descsz)
+				  + sizeof (note->type) + namesz;
+		  so->build_id = xmalloc (descsz);
+		  so->build_idsz = descsz;
+		  memcpy (so->build_id, note_raw + build_id_offs, descsz);
+		}
+	    }
+	  xfree (note_raw);
+	}
+    }
 }
 
 
@@ -2458,4 +2548,5 @@ _initialize_svr4_solib (void)
   svr4_so_ops.lookup_lib_global_symbol = elf_lookup_lib_symbol;
   svr4_so_ops.same = svr4_same;
   svr4_so_ops.keep_data_in_core = svr4_keep_data_in_core;
+  svr4_so_ops.validate = svr4_validate;
 }
diff --git a/gdb/solib-svr4.h b/gdb/solib-svr4.h
index 66a06e1..ba17dbe 100644
--- a/gdb/solib-svr4.h
+++ b/gdb/solib-svr4.h
@@ -20,6 +20,9 @@
 #ifndef SOLIB_SVR4_H
 #define SOLIB_SVR4_H
 
+#define DYNAMIC_NAME ".dynamic"
+#define NOTE_GNU_BUILD_ID_NAME  ".note.gnu.build-id"
+
 struct objfile;
 struct target_so_ops;
 
diff --git a/gdb/solib-target.c b/gdb/solib-target.c
index d897bc0..ed82218 100644
--- a/gdb/solib-target.c
+++ b/gdb/solib-target.c
@@ -25,6 +25,7 @@
 #include "target.h"
 #include "vec.h"
 #include "solib-target.h"
+#include "solib.h"
 
 #include "gdb_string.h"
 
@@ -500,6 +501,7 @@ _initialize_solib_target (void)
   solib_target_so_ops.in_dynsym_resolve_code
     = solib_target_in_dynsym_resolve_code;
   solib_target_so_ops.bfd_open = solib_bfd_open;
+  solib_target_so_ops.validate = default_solib_validate;
 
   /* Set current_target_so_ops to solib_target_so_ops if not already
      set.  */
diff --git a/gdb/solib.c b/gdb/solib.c
index 8129c0f..89503ab 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -495,6 +495,17 @@ solib_map_sections (struct so_list *so)
 	}
     }
 
+  gdb_assert (ops->validate != NULL);
+
+  if (!ops->validate (so))
+    {
+      warning (_("Shared object \"%s\" could not be validated "
+		 "and will be ignored."), so->so_name);
+      gdb_bfd_unref (so->abfd);
+      so->abfd = NULL;
+      return 0;
+    }
+
   /* Add the shared object's sections to the current set of file
      section tables.  Do this immediately after mapping the object so
      that later nodes in the list can query this object, as is needed
@@ -551,6 +562,7 @@ free_so (struct so_list *so)
 {
   struct target_so_ops *ops = solib_ops (target_gdbarch ());
 
+  xfree (so->build_id);
   free_so_symbols (so);
   ops->free_so (so);
 
@@ -1448,6 +1460,14 @@ gdb_bfd_lookup_symbol (bfd *abfd,
   return symaddr;
 }
 
+/* Default implementation does not perform any validation.  */
+
+int
+default_solib_validate (const struct so_list *const so)
+{
+  return 1; /* No validation.  */
+}
+
 extern initialize_file_ftype _initialize_solib; /* -Wmissing-prototypes */
 
 void
diff --git a/gdb/solib.h b/gdb/solib.h
index b811866..670949a 100644
--- a/gdb/solib.h
+++ b/gdb/solib.h
@@ -90,4 +90,8 @@ extern CORE_ADDR gdb_bfd_lookup_symbol_from_symtab (bfd *abfd,
 								      void *),
 						    void *data);
 
+/* Default validation always returns 1.  */
+
+extern int default_solib_validate (const struct so_list *so);
+
 #endif /* SOLIB_H */
diff --git a/gdb/solist.h b/gdb/solist.h
index f784fc3..72e003d 100644
--- a/gdb/solist.h
+++ b/gdb/solist.h
@@ -75,6 +75,16 @@ struct so_list
        There may not be just one (e.g. if two segments are relocated
        differently); but this is only used for "info sharedlibrary".  */
     CORE_ADDR addr_low, addr_high;
+
+    /* Build id in raw format, contains verbatim contents of
+       .note.gnu.build-id including note header.  This is actual
+       BUILD_ID which comes either from the remote target via qXfer
+       packet or via reading target memory.  Therefore, it may differ
+       from the build-id of the associated bfd.  In a normal
+       scenario, this so would soon lose its abfd due to failed
+       validation.  */
+    size_t build_idsz;
+    gdb_byte *build_id;
   };
 
 struct target_so_ops
@@ -148,6 +158,10 @@ struct target_so_ops
        core file (in particular, for readonly sections).  */
     int (*keep_data_in_core) (CORE_ADDR vaddr,
 			      unsigned long size);
+
+    /* Return 0 if SO does not match target SO it is supposed to
+       represent.  Return 1 otherwise.  */
+    int (*validate) (const struct so_list *so);
   };
 
 /* Free the memory associated with a (so_list *).  */
-- 
1.7.10.4