Bug#758826: [patch] fix if $HOME is not writable

[Michael Vogt]

Package: debsig-verify
Version: 0.10

Hi,

I ran into a issue today that debsig-verify would fail if $HOME was
not writable to the debsig-verify progress. The reason is that gpg
tries to create/read a ~/.gnupg/{pubring,secring}.gpg.

Attached is a patch that run gpg with its own GNUPGHOME instead of the
users.

Feedback welcome!

Thanks,
 Michael

diff -Nru debsig-verify-0.10/gpg-parse.c debsig-verify-0.10ubuntu1/gpg-parse.c
--- debsig-verify-0.10/gpg-parse.c	2014-06-07 22:17:34.000000000 +0200
+++ debsig-verify-0.10ubuntu1/gpg-parse.c	2014-08-21 20:59:04.000000000 +0200
@@ -32,16 +32,28 @@
 #include "debsig.h"
 
 static int gpg_inited = 0;
+static char gpg_tmpdir[256] = {0,};
 
-/* Crazy damn hack to make sure gpg has created ~/.gnupg, else it will
- * fail first time called */
+/* Crazy damn hack to make sure gpg has a writable HOME to put its 
+   trustdb and secret keyring etc */
+static void cleanup_gpg_tmpdir(void) {
+   execl("/bin/rm", "rm", "-rf", gpg_tmpdir, NULL);
+}
 static void gpg_init(void) {
     int rc;
 
-    if (gpg_inited) return;
-    rc = system(GPG_PROG" --options /dev/null < /dev/null > /dev/null 2>&1");
-    if (rc < 0)
-        ds_fail_printf(DS_FAIL_INTERNAL, "error writing initializing gpg");
+    if (gpg_inited)
+       return;
+
+    char *tmpdir = getenv("TMPDIR");
+    if(!tmpdir)
+       tmpdir = "/tmp";
+    snprintf(gpg_tmpdir, sizeof(gpg_tmpdir) -1, 
+             "%s/%s", tmpdir, "debsig-verify.XXXXXX");
+    if(!mkdtemp(gpg_tmpdir))
+       ds_fail_printf(DS_FAIL_INTERNAL, "mkdtemp() failed for '%s'", gpg_tmpdir);
+    setenv("GNUPGHOME", gpg_tmpdir, 1);
+    atexit(cleanup_gpg_tmpdir);
     gpg_inited = 1;
 }