From 71413f4ee9a2d345da059793e795d798924b2209 Mon Sep 17 00:00:00 2001
From: Ethan Yonker <dees_troy@teamw.in>
Date: Wed, 26 Feb 2014 13:36:08 -0600
Subject: Check crypto footer before offering to decrypt

Verify that we have a valid footer with proper magic before
setting things up for decryption to help prevent user confusion
when dealing with data partitions that fail to mount. Also check
to make sure that the block device for /data is present.

Change-Id: Ie87818fe4505a8bf71df7d3934c114e7328ef3ca
---
 crypto/jb/cryptfs.c | 23 +++++++++++++++++++++--
 crypto/jb/cryptfs.h |  1 +
 2 files changed, 22 insertions(+), 2 deletions(-)

(limited to 'crypto/jb')

diff --git a/crypto/jb/cryptfs.c b/crypto/jb/cryptfs.c
index 4e5706b64..f9c0d7489 100644
--- a/crypto/jb/cryptfs.c
+++ b/crypto/jb/cryptfs.c
@@ -1354,13 +1354,32 @@ int cryptfs_crypto_complete(void)
 
 #define FSTAB_PREFIX "/fstab."
 
+int cryptfs_check_footer(void)
+{
+    int rc = -1;
+    char fstab_filename[PROPERTY_VALUE_MAX + sizeof(FSTAB_PREFIX)];
+    char propbuf[PROPERTY_VALUE_MAX];
+    struct crypt_mnt_ftr crypt_ftr;
+
+    property_get("ro.hardware", propbuf, "");
+    snprintf(fstab_filename, sizeof(fstab_filename), FSTAB_PREFIX"%s", propbuf);
+
+    fstab = fs_mgr_read_fstab(fstab_filename);
+    if (!fstab) {
+        printf("failed to open %s\n", fstab_filename);
+        return -1;
+    }
+
+    rc = get_crypt_ftr_and_key(&crypt_ftr);
+
+    return rc;
+}
+
 int cryptfs_check_passwd(char *passwd)
 {
     int rc = -1;
     char fstab_filename[PROPERTY_VALUE_MAX + sizeof(FSTAB_PREFIX)];
     char propbuf[PROPERTY_VALUE_MAX];
-    int i;
-    int flags;
 
     property_get("ro.hardware", propbuf, "");
     snprintf(fstab_filename, sizeof(fstab_filename), FSTAB_PREFIX"%s", propbuf);
diff --git a/crypto/jb/cryptfs.h b/crypto/jb/cryptfs.h
index 162159eb0..d815814d3 100644
--- a/crypto/jb/cryptfs.h
+++ b/crypto/jb/cryptfs.h
@@ -139,6 +139,7 @@ extern "C" {
   typedef void (*kdf_func)(char *passwd, unsigned char *salt, unsigned char *ikey, void *params);
 
   int cryptfs_crypto_complete(void);
+  int cryptfs_check_footer(void);
   int cryptfs_check_passwd(char *pw);
   int cryptfs_verify_passwd(char *newpw);
   int cryptfs_restart(void);
-- 
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