Refine size constraints applied to win32pstatus ELF notes

Don't reject any win32pstatus notes smaller than minimum size for a
NOTE_INFO_THREAD.

This only happens to work because the Cygwin dumper tool currently
writes all these notes as the largest size of the union, (which wastes
lots of space in the core dump).

Instead, apply the appropriate size constraint for each win32pstatus
note type.

bfd/ChangeLog:

2020-07-11  Jon Turney  <jon.turney@dronecode.org.uk>

	* elf.c (elfcore_grok_win32pstatus): Don't apply size constraint
	for NOTE_INFO_THREAD to all win32pstatus ELF notes, instead apply
	appropriate size constraint for each win32pstatus note type.

1 files changed, 16 insertions, 1 deletions

diff --git a/bfd/elf.c b/bfd/elf.c
index 43a6cba..171880d 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -10139,12 +10139,13 @@ elfcore_grok_win32pstatus (bfd *abfd, Elf_Internal_Note *note)
   char buf[30];
   char *name;
   size_t len;
+  size_t name_size;
   asection *sect;
   int type;
   int is_active_thread;
   bfd_vma base_addr;
 
-  if (note->descsz < 728)
+  if (note->descsz < 4)
     return TRUE;
 
   if (! CONST_STRNEQ (note->namedata, "win32"))
@@ -10155,12 +10156,18 @@ elfcore_grok_win32pstatus (bfd *abfd, Elf_Internal_Note *note)
   switch (type)
     {
     case NOTE_INFO_PROCESS:
+      if (note->descsz < 12)
+        return FALSE;
+
       /* FIXME: need to add ->core->command.  */
       elf_tdata (abfd)->core->pid = bfd_get_32 (abfd, note->descdata + 4);
       elf_tdata (abfd)->core->signal = bfd_get_32 (abfd, note->descdata + 8);
       break;
 
     case NOTE_INFO_THREAD:
+      if (note->descsz < 12)
+        return FALSE;
+
       /* Make a ".reg/<tid>" section containing the Win32 API thread CONTEXT
          structure. */
       /* thread_info.tid */
@@ -10192,6 +10199,9 @@ elfcore_grok_win32pstatus (bfd *abfd, Elf_Internal_Note *note)
       break;
 
     case NOTE_INFO_MODULE:
+      if (note->descsz < 12)
+        return FALSE;
+
       /* Make a ".module/xxxxxxxx" section.  */
       /* module_info.base_address */
       base_addr = bfd_get_32 (abfd, note->descdata + 4);
@@ -10209,6 +10219,11 @@ elfcore_grok_win32pstatus (bfd *abfd, Elf_Internal_Note *note)
       if (sect == NULL)
 	return FALSE;
 
+      /* module_info.module_name_size */
+      name_size = bfd_get_32 (abfd, note->descdata + 8);
+      if (note->descsz < 12 + name_size)
+        return FALSE;
+
       sect->size = note->descsz;
       sect->filepos = note->descpos;
       sect->alignment_power = 2;