From d3edaa91d4cf7202ec14342410194841e2f67f12 Mon Sep 17 00:00:00 2001
From: Alan Modra <amodra@gmail.com>
Date: Fri, 26 Feb 2021 11:30:32 +1030
Subject: [PATCH] Reinstate various pieces backed out from smart_rename changes

In the interests of a stable release various last minute smart_rename
patches were backed out of the 2.36 branch.  The main reason to
reinstate some of those backed out changes here is to make necessary
followup fixes to commit 8e03235147a9 simple cherry-picks from
mainline.  A secondary reason is that ar -M support isn't fixed for
pr26945 without this patch.

        PR 26945
        * ar.c: Don't include libbfd.h.
        (write_archive): Replace xmalloc+strcpy with xstrdup.
        * arsup.c (temp_name, real_ofd): New static variables.
        (ar_open): Use make_tempname and bfd_fdopenw.
        (ar_save): Adjust to suit ar_open changes.
        * objcopy.c: Don't include libbfd.h.
        * rename.c: Rename and reorder variables.

(cherry picked from commit 95b91a043aeaeb546d2fea556d84a2de1e917770)

Upstream-Status: Backport [https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d3edaa91d4cf7202ec14342410194841e2f67f12]
CVE: CVE-2021-20197
Signed-off-by: Vinay Kumar <vinay.m.engg@gmail.com>
---
 binutils/ar.c      |   6 +-
 binutils/arsup.c   |  37 ++++++++----
 binutils/bucomm.h  |   3 +-
 binutils/objcopy.c |   9 +--
 binutils/rename.c  | 148 +++++++++++----------------------------------
 5 files changed, 67 insertions(+), 136 deletions(-)

diff --git a/binutils/ar.c b/binutils/ar.c
index 45a34e3a6cf..44df48c5c67 100644
--- a/binutils/ar.c
+++ b/binutils/ar.c
@@ -25,7 +25,6 @@
 
 #include "sysdep.h"
 #include "bfd.h"
-#include "libbfd.h"
 #include "libiberty.h"
 #include "progress.h"
 #include "getopt.h"
@@ -1255,8 +1254,7 @@ write_archive (bfd *iarch)
   bfd *contents_head = iarch->archive_next;
   int ofd = -1;
 
-  old_name = (char *) xmalloc (strlen (bfd_get_filename (iarch)) + 1);
-  strcpy (old_name, bfd_get_filename (iarch));
+  old_name = xstrdup (bfd_get_filename (iarch));
   new_name = make_tempname (old_name, &ofd);
 
   if (new_name == NULL)
@@ -1308,7 +1306,7 @@ write_archive (bfd *iarch)
   /* We don't care if this fails; we might be creating the archive.  */
   bfd_close (iarch);
 
-  if (smart_rename (new_name, old_name, 0) != 0)
+  if (smart_rename (new_name, old_name, NULL) != 0)
     xexit (1);
   free (old_name);
   free (new_name);
diff --git a/binutils/arsup.c b/binutils/arsup.c
index 5403a0c5d74..f7ce8f0bc82 100644
--- a/binutils/arsup.c
+++ b/binutils/arsup.c
@@ -42,6 +42,8 @@ extern int deterministic;
 
 static bfd *obfd;
 static char *real_name;
+static char *temp_name;
+static int real_ofd;
 static FILE *outfile;
 
 static void
@@ -149,27 +151,24 @@ maybequit (void)
 void
 ar_open (char *name, int t)
 {
-  char *tname;
-  const char *bname = lbasename (name);
-  real_name = name;
+  real_name = xstrdup (name);
+  temp_name = make_tempname (real_name, &real_ofd);
 
-  /* Prepend tmp- to the beginning, to avoid file-name clashes after
-     truncation on filesystems with limited namespaces (DOS).  */
-  if (asprintf (&tname, "%.*stmp-%s", (int) (bname - name), name, bname) == -1)
+  if (temp_name == NULL)
     {
-      fprintf (stderr, _("%s: Can't allocate memory for temp name (%s)\n"),
+      fprintf (stderr, _("%s: Can't open temporary file (%s)\n"),
 	       program_name, strerror(errno));
       maybequit ();
       return;
     }
 
-  obfd = bfd_openw (tname, NULL);
+  obfd = bfd_fdopenw (temp_name, NULL, real_ofd);
 
   if (!obfd)
     {
       fprintf (stderr,
 	       _("%s: Can't open output archive %s\n"),
-	       program_name,  tname);
+	       program_name, temp_name);
 
       maybequit ();
     }
@@ -344,16 +343,30 @@ ar_save (void)
     }
   else
     {
-      char *ofilename = xstrdup (bfd_get_filename (obfd));
+      struct stat target_stat;
 
       if (deterministic > 0)
         obfd->flags |= BFD_DETERMINISTIC_OUTPUT;
 
       bfd_close (obfd);
 
-      smart_rename (ofilename, real_name, 0);
+      if (stat (real_name, &target_stat) != 0)
+	{
+	  /* The temp file created in ar_open has mode 0600 as per mkstemp.
+	     Create the real empty output file here so smart_rename will
+	     update the mode according to the process umask.  */
+	  obfd = bfd_openw (real_name, NULL);
+	  if (obfd != NULL)
+	    {
+	      bfd_set_format (obfd, bfd_archive);
+	      bfd_close (obfd);
+	    }
+	}
+
+      smart_rename (temp_name, real_name, NULL);
       obfd = 0;
-      free (ofilename);
+      free (temp_name);
+      free (real_name);
     }
 }
 
diff --git a/binutils/bucomm.h b/binutils/bucomm.h
index 91f6a5b228f..aa7e33d8cd1 100644
--- a/binutils/bucomm.h
+++ b/binutils/bucomm.h
@@ -71,7 +71,8 @@ extern void print_version (const char *);
 /* In rename.c.  */
 extern void set_times (const char *, const struct stat *);
 
-extern int smart_rename (const char *, const char *, int);
+extern int smart_rename (const char *, const char *, struct stat *);
+
 
 /* In libiberty.  */
 void *xmalloc (size_t);
diff --git a/binutils/objcopy.c b/binutils/objcopy.c
index eab3b6db585..73aa8bc2514 100644
--- a/binutils/objcopy.c
+++ b/binutils/objcopy.c
@@ -20,7 +20,6 @@
 
 #include "sysdep.h"
 #include "bfd.h"
-#include "libbfd.h"
 #include "progress.h"
 #include "getopt.h"
 #include "libiberty.h"
@@ -4861,12 +4860,10 @@ strip_main (int argc, char *argv[])
 		 output_target, NULL);
       if (status == 0)
 	{
-	  if (preserve_dates)
-	    set_times (tmpname, &statbuf);
 	  if (output_file != tmpname)
 	    status = (smart_rename (tmpname,
 				    output_file ? output_file : argv[i],
-				    preserve_dates) != 0);
+				    preserve_dates ? &statbuf : NULL) != 0);
 	  if (status == 0)
 	    status = hold_status;
 	}
@@ -5931,11 +5928,9 @@ copy_main (int argc, char *argv[])
 	     output_target, input_arch);
   if (status == 0)
     {
-      if (preserve_dates)
-	set_times (tmpname, &statbuf);
       if (tmpname != output_filename)
 	status = (smart_rename (tmpname, input_filename,
-				preserve_dates) != 0);
+				preserve_dates ? &statbuf : NULL) != 0);
     }
   else
     unlink_if_ordinary (tmpname);
diff --git a/binutils/rename.c b/binutils/rename.c
index 65ad5bf52c4..72a9323d72c 100644
--- a/binutils/rename.c
+++ b/binutils/rename.c
@@ -24,14 +24,9 @@
 
 #ifdef HAVE_GOOD_UTIME_H
 #include <utime.h>
-#else /* ! HAVE_GOOD_UTIME_H */
-#ifdef HAVE_UTIMES
+#elif defined HAVE_UTIMES
 #include <sys/time.h>
-#endif /* HAVE_UTIMES */
-#endif /* ! HAVE_GOOD_UTIME_H */
-
-#if ! defined (_WIN32) || defined (__CYGWIN32__)
-static int simple_copy (const char *, const char *);
+#endif
 
 /* The number of bytes to copy at once.  */
 #define COPY_BUF 8192
@@ -82,7 +77,6 @@ simple_copy (const char *from, const char *to)
     }
   return 0;
 }
-#endif /* __CYGWIN32__ or not _WIN32 */
 
 /* Set the times of the file DESTINATION to be the same as those in
    STATBUF.  */
@@ -91,122 +85,52 @@ void
 set_times (const char *destination, const struct stat *statbuf)
 {
   int result;
-
-  {
 #ifdef HAVE_GOOD_UTIME_H
-    struct utimbuf tb;
-
-    tb.actime = statbuf->st_atime;
-    tb.modtime = statbuf->st_mtime;
-    result = utime (destination, &tb);
-#else /* ! HAVE_GOOD_UTIME_H */
-#ifndef HAVE_UTIMES
-    long tb[2];
-
-    tb[0] = statbuf->st_atime;
-    tb[1] = statbuf->st_mtime;
-    result = utime (destination, tb);
-#else /* HAVE_UTIMES */
-    struct timeval tv[2];
-
-    tv[0].tv_sec = statbuf->st_atime;
-    tv[0].tv_usec = 0;
-    tv[1].tv_sec = statbuf->st_mtime;
-    tv[1].tv_usec = 0;
-    result = utimes (destination, tv);
-#endif /* HAVE_UTIMES */
-#endif /* ! HAVE_GOOD_UTIME_H */
-  }
+  struct utimbuf tb;
+
+  tb.actime = statbuf->st_atime;
+  tb.modtime = statbuf->st_mtime;
+  result = utime (destination, &tb);
+#elif defined HAVE_UTIMES
+  struct timeval tv[2];
+
+  tv[0].tv_sec = statbuf->st_atime;
+  tv[0].tv_usec = 0;
+  tv[1].tv_sec = statbuf->st_mtime;
+  tv[1].tv_usec = 0;
+  result = utimes (destination, tv);
+#else
+  long tb[2];
+
+  tb[0] = statbuf->st_atime;
+  tb[1] = statbuf->st_mtime;
+  result = utime (destination, tb);
+#endif
 
   if (result != 0)
     non_fatal (_("%s: cannot set time: %s"), destination, strerror (errno));
 }
 
-#ifndef S_ISLNK
-#ifdef S_IFLNK
-#define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
-#else
-#define S_ISLNK(m) 0
-#define lstat stat
-#endif
-#endif
-
-/* Rename FROM to TO, copying if TO is a link.
-   Return 0 if ok, -1 if error.  */
+/* Copy FROM to TO.  TARGET_STAT has the file status that, if non-NULL,
+   is used to fix up timestamps.  Return 0 if ok, -1 if error.
+   At one time this function renamed files, but file permissions are
+   tricky to update given the number of different schemes used by
+   various systems.  So now we just copy.  */
 
 int
-smart_rename (const char *from, const char *to, int preserve_dates ATTRIBUTE_UNUSED)
+smart_rename (const char *from, const char *to,
+	      struct stat *target_stat)
 {
-  bfd_boolean exists;
-  struct stat s;
-  int ret = 0;
-
-  exists = lstat (to, &s) == 0;
-
-#if defined (_WIN32) && !defined (__CYGWIN32__)
-  /* Win32, unlike unix, will not erase `to' in `rename(from, to)' but
-     fail instead.  Also, chown is not present.  */
+  int ret;
 
-  if (exists)
-    remove (to);
-
-  ret = rename (from, to);
+  ret = simple_copy (from, to);
   if (ret != 0)
-    {
-      /* We have to clean up here.  */
-      non_fatal (_("unable to rename '%s'; reason: %s"), to, strerror (errno));
-      unlink (from);
-    }
-#else
-  /* Use rename only if TO is not a symbolic link and has
-     only one hard link, and we have permission to write to it.  */
-  if (! exists
-      || (!S_ISLNK (s.st_mode)
-	  && S_ISREG (s.st_mode)
-	  && (s.st_mode & S_IWUSR)
-	  && s.st_nlink == 1)
-      )
-    {
-      ret = rename (from, to);
-      if (ret == 0)
-	{
-	  if (exists)
-	    {
-	      /* Try to preserve the permission bits and ownership of
-		 TO.  First get the mode right except for the setuid
-		 bit.  Then change the ownership.  Then fix the setuid
-		 bit.  We do the chmod before the chown because if the
-		 chown succeeds, and we are a normal user, we won't be
-		 able to do the chmod afterward.  We don't bother to
-		 fix the setuid bit first because that might introduce
-		 a fleeting security problem, and because the chown
-		 will clear the setuid bit anyhow.  We only fix the
-		 setuid bit if the chown succeeds, because we don't
-		 want to introduce an unexpected setuid file owned by
-		 the user running objcopy.  */
-	      chmod (to, s.st_mode & 0777);
-	      if (chown (to, s.st_uid, s.st_gid) >= 0)
-		chmod (to, s.st_mode & 07777);
-	    }
-	}
-      else
-	{
-	  /* We have to clean up here.  */
-	  non_fatal (_("unable to rename '%s'; reason: %s"), to, strerror (errno));
-	  unlink (from);
-	}
-    }
-  else
-    {
-      ret = simple_copy (from, to);
-      if (ret != 0)
-	non_fatal (_("unable to copy file '%s'; reason: %s"), to, strerror (errno));
+    non_fatal (_("unable to copy file '%s'; reason: %s"),
+	       to, strerror (errno));
 
-      if (preserve_dates)
-	set_times (to, &s);
-      unlink (from);
-    }
-#endif /* _WIN32 && !__CYGWIN32__ */
+  if (target_stat != NULL)
+    set_times (to, target_stat);
+  unlink (from);
 
   return ret;
 }
-- 
2.17.1