pam_ecryptfs: Respect ~/.ecryptfs/wrapping-independent

pam_ecryptfs: Respect ~/.ecryptfs/wrapping-independent

Quoting man ecryptfs-mount-private:
>    ~/.ecryptfs/wrapping-independent  -  this  file  exists  if the
>           wrapping passphrase is independent from login passphrase

This patch makes pam_ecryptfs check if this file exists and ask the
user for the wrapping passphrase if it does.
---
 src/pam_ecryptfs/pam_ecryptfs.c |   13 ++++++++-----
 1 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/pam_ecryptfs/pam_ecryptfs.c b/src/pam_ecryptfs/pam_ecryptfs.c
index 2209ac8..2d64587 100644
--- a/src/pam_ecryptfs/pam_ecryptfs.c
+++ b/src/pam_ecryptfs/pam_ecryptfs.c
@@ -68,13 +68,13 @@ static void error(const char *msg)
    }
 }

-/* returns: 0 for pam automounting not set, 1 for set, <0 for error */
-static int ecryptfs_pam_automount_set(const char *homedir)
+/* returns: 0 if file does not exist, 1 if it exists, <0 for error */
+static int file_exists_dotecryptfs(const char *homedir, char *filename)
 {
    char *file_path;
    int rc = 0;
    struct stat s;
-   if (asprintf(&file_path, "%s/.ecryptfs/auto-mount", homedir) == -1)
+   if (asprintf(&file_path, "%s/.ecryptfs/%s", homedir, filename) == -1)
        return -ENOMEM;
    if (stat(file_path, &s) != 0) {
        if (errno != ENOENT)
@@ -149,7 +149,7 @@ PAM_EXTERN int pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc,
               "rc = [%ld]\n", username, rc);
        goto out;
    }
-   if (!ecryptfs_pam_automount_set(homedir))
+   if (!file_exists_dotecryptfs(homedir, "auto-mount"))
        goto out;
    private_mnt = ecryptfs_fetch_private_mnt(homedir);
    if (ecryptfs_private_is_mounted(NULL, private_mnt, NULL, 1)) {
@@ -165,7 +165,10 @@ PAM_EXTERN int pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc,
        syslog(LOG_WARNING, "Can't check if kernel supports ecryptfs\n");
    saved_uid = geteuid();
    seteuid(uid);
-   rc = pam_get_item(pamh, PAM_AUTHTOK, (const void **)&passphrase);
+   if(file_exists_dotecryptfs(homedir, "wrapping-independent") == 1)
+       rc = pam_prompt(pamh, PAM_PROMPT_ECHO_OFF, &passphrase, "Encryption passphrase: ");
+   else
+       rc = pam_get_item(pamh, PAM_AUTHTOK, (const void **)&passphrase);
    seteuid(saved_uid);
    if (rc != PAM_SUCCESS) {
        syslog(LOG_ERR, "Error retrieving passphrase; rc = [%ld]\n",
--
1.7.0.4