[OE-core] [PATCH] patch.bbclass: increase security

[Constantin Musca]

- Use mkdtemp for generating temp dir names
- Use bb.utils.remove for removing temp dirs
- Add comment for explaining the "patch" workaround

Signed-off-by: Constantin Musca <constantinx.musca at intel.com>
---
 meta/classes/patch.bbclass |   16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/meta/classes/patch.bbclass b/meta/classes/patch.bbclass
index d010438..4b535d9 100644
--- a/meta/classes/patch.bbclass
+++ b/meta/classes/patch.bbclass
@@ -139,10 +139,14 @@ python patch_do_patch() {
     path = os.getenv('PATH')
     os.putenv('PATH', d.getVar('PATH', True))
 
-    import shutil
-    process_tmpdir = os.path.join('/tmp', str(os.getpid()))
+    # We must use one TMPDIR per process (/tmp/${PID}${random_chars})
+    # so that the "patch" processes don't generate the same temp
+    # file name.
+
+    import tempfile
+    process_tmpdir = tempfile.mkdtemp(prefix=str(os.getpid()))
     if os.path.exists(process_tmpdir):
-        shutil.rmtree(process_tmpdir)
+        bb.utils.remove(process_tmpdir, True)
     os.makedirs(process_tmpdir)
     os.environ['TMPDIR'] = process_tmpdir
 
@@ -168,15 +172,15 @@ python patch_do_patch() {
         try:
             patchset.Import({"file":local, "strippath": parm['striplevel']}, True)
         except Exception as exc:
-            shutil.rmtree(process_tmpdir)
+            bb.utils.remove(process_tmpdir, True)
             bb.fatal(str(exc))
         try:
             resolver.Resolve()
         except bb.BBHandledException as e:
-            shutil.rmtree(process_tmpdir)
+            bb.utils.remove(process_tmpdir, True)
             bb.fatal(str(e))
 
-    shutil.rmtree(process_tmpdir)
+    bb.utils.remove(process_tmpdir, True)
 }
 patch_do_patch[vardepsexclude] = "PATCHRESOLVE"
 
-- 
1.7.9.5