gold patch committed: better handling of invalid archives

gold patch committed: better handling of invalid archives

[Ian Lance Taylor]

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This gold patch improves the handling of invalid archives.  Before the
linker would try to carry on after determining that the archive was
invalid, leading to crashes.  This changes the linker to stop trying to
process the archive once it has failed to parse it.  Committed to
mainline.

Ian


2011-03-27  Ian Lance Taylor  <iant@google.com>

	* archive.cc (Archive::interpret_header): Return -1 if something
	goes wrong.  Change callers accordingly.



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Index: archive.cc
===================================================================
RCS file: /cvs/src/src/gold/archive.cc,v
retrieving revision 1.63
diff -p -u -r1.63 archive.cc
--- archive.cc	24 Jan 2011 21:48:40 -0000	1.63
+++ archive.cc	27 Mar 2011 16:44:14 -0000
@@ -109,9 +109,11 @@ Archive::setup()
 
   // The first member of the archive should be the symbol table.
   std::string armap_name;
-  section_size_type armap_size =
-    convert_to_section_size_type(this->read_header(sarmag, false,
-						   &armap_name, NULL));
+  off_t header_size = this->read_header(sarmag, false, &armap_name, NULL);
+  if (header_size == -1)
+    return;
+
+  section_size_type armap_size = convert_to_section_size_type(header_size);
   off_t off = sarmag;
   if (armap_name.empty())
     {
@@ -128,8 +130,11 @@ Archive::setup()
   if ((off & 1) != 0)
     ++off;
   std::string xname;
-  section_size_type extended_size =
-    convert_to_section_size_type(this->read_header(off, true, &xname, NULL));
+  header_size = this->read_header(off, true, &xname, NULL);
+  if (header_size == -1)
+    return;
+
+  section_size_type extended_size = convert_to_section_size_type(header_size);
   if (xname == "/")
     {
       const unsigned char* p = this->get_view(off + sizeof(Archive_header),
@@ -227,8 +232,8 @@ Archive::read_header(off_t off, bool cac
 }
 
 // Interpret the header of HDR, the header of the archive member at
-// file offset OFF.  Fail if something goes wrong.  Return the size of
-// the member.  Set *PNAME to the name of the member.
+// file offset OFF.  Return the size of the member, or -1 if something
+// has gone wrong.  Set *PNAME to the name of the member.
 
 off_t
 Archive::interpret_header(const Archive_header* hdr, off_t off,
@@ -238,7 +243,7 @@ Archive::interpret_header(const Archive_
     {
       gold_error(_("%s: malformed archive header at %zu"),
 		 this->name().c_str(), static_cast<size_t>(off));
-      return this->input_file_->file().filesize() - off;
+      return -1;
     }
 
   const int size_string_size = sizeof hdr->ar_size;
@@ -258,7 +263,7 @@ Archive::interpret_header(const Archive_
     {
       gold_error(_("%s: malformed archive header size at %zu"),
 		 this->name().c_str(), static_cast<size_t>(off));
-      return this->input_file_->file().filesize() - off;
+      return -1;
     }
 
   if (hdr->ar_name[0] != '/')
@@ -269,7 +274,7 @@ Archive::interpret_header(const Archive_
 	{
 	  gold_error(_("%s: malformed archive header name at %zu"),
 		     this->name().c_str(), static_cast<size_t>(off));
-	  return this->input_file_->file().filesize() - off;
+	  return -1;
 	}
       pname->assign(hdr->ar_name, name_end - hdr->ar_name);
       if (nested_off != NULL)
@@ -300,7 +305,7 @@ Archive::interpret_header(const Archive_
 	{
 	  gold_error(_("%s: bad extended name index at %zu"),
 		     this->name().c_str(), static_cast<size_t>(off));
-	  return this->input_file_->file().filesize() - off;
+	  return -1;
 	}
 
       const char* name = this->extended_names_.data() + x;
@@ -310,7 +315,7 @@ Archive::interpret_header(const Archive_
 	{
 	  gold_error(_("%s: bad extended name entry at header %zu"),
 		     this->name().c_str(), static_cast<size_t>(off));
-	  return this->input_file_->file().filesize() - off;
+	  return -1;
 	}
       pname->assign(name, name_end - 1 - name);
       if (nested_off != NULL)
@@ -418,9 +423,16 @@ Archive::const_iterator::read_next_heade
       this->archive_->file().read(this->off_, sizeof(Archive_header), buf);
 
       const Archive_header* hdr = reinterpret_cast<const Archive_header*>(buf);
-      this->header_.size =
-	this->archive_->interpret_header(hdr, this->off_, &this->header_.name,
-					 &this->header_.nested_off);
+      off_t size = this->archive_->interpret_header(hdr, this->off_,
+						    &this->header_.name,
+						    &this->header_.nested_off);
+      if (size == -1)
+	{
+	  this->header_.off = filesize;
+	  return;
+	}
+
+      this->header_.size = size;
       this->header_.off = this->off_;
 
       // Skip special members.
@@ -462,6 +474,8 @@ Archive::get_file_and_offset(off_t off, 
   off_t nested_off;
 
   *memsize = this->read_header(off, false, member_name, &nested_off);
+  if (*memsize == -1)
+    return false;
 
   *input_file = this->input_file_;
   *memoff = off + static_cast<off_t>(sizeof(Archive_header));