tools/patch: Add fedora patch for crashing git style patches

https://lists.gnu.org/archive/html/bug-patch/2018-10/msg00000.html

I assume a CVE number will be assigned soon.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/tools/patch/patches/040-Fix-error-handling-with-git-style-patches.patch b/tools/patch/patches/040-Fix-error-handling-with-git-style-patches.patch
new file mode 100644
index 0000000000..5cc958e746
--- /dev/null
+++ b/tools/patch/patches/040-Fix-error-handling-with-git-style-patches.patch
@@ -0,0 +1,53 @@
+From 424da221cec76ea200cff1fa9b08a6f3d94c28a7 Mon Sep 17 00:00:00 2001
+From: Lubomir Rintel <lkundrak@v3.sk>
+Date: Wed, 31 Oct 2018 16:39:13 -0700
+Subject: [PATCH] Fix error handling with git-style patches
+
+When an error is encountered in output_files(), the subsequent call to
+cleanup() calls back into output_files() resulting in an infinte recursion.
+This is trivially reproduced with a git-style patch (which utilizes
+output_file_later()) that tries to patch a nonexistent or unreadable
+file (see attached test case).
+
+* src/patch.c: (output_files) clear the files_to_output list before
+iterating it, so that recursive calls won't iterate the same files.
+---
+ src/patch.c | 12 ++++++++----
+ 1 file changed, 8 insertions(+), 4 deletions(-)
+
+--- a/src/patch.c
++++ b/src/patch.c
+@@ -1938,8 +1938,12 @@ output_files (struct stat const *st)
+ {
+   gl_list_iterator_t iter;
+   const void *elt;
++  gl_list_t files;
+ 
+-  iter = gl_list_iterator (files_to_output);
++  files = files_to_output;
++  init_files_to_output ();
++
++  iter = gl_list_iterator (files);
+   while (gl_list_iterator_next (&iter, &elt, NULL))
+     {
+       const struct file_to_output *file_to_output = elt;
+@@ -1957,8 +1961,8 @@ output_files (struct stat const *st)
+ 	  /* Free the list up to here. */
+ 	  for (;;)
+ 	    {
+-	      const void *elt2 = gl_list_get_at (files_to_output, 0);
+-	      gl_list_remove_at (files_to_output, 0);
++	      const void *elt2 = gl_list_get_at (files, 0);
++	      gl_list_remove_at (files, 0);
+ 	      if (elt == elt2)
+ 		break;
+ 	    }
+@@ -1967,7 +1971,7 @@ output_files (struct stat const *st)
+ 	}
+     }
+   gl_list_iterator_free (&iter);
+-  gl_list_clear (files_to_output);
++  gl_list_clear (files);
+ }
+ 
+ /* Fatal exit with cleanup. */