-O okey=val: offset into key (useful for block device keys, such as USB sticks).

[tfcrypt.git] / tfcrypt.c

diff --git a/tfcrypt.c b/tfcrypt.c
index 8608cf16011399202e66f08b8855211c6368a56e..df62420769d0b07b0db2a72a424cb72f6885d081 100644 (file)
--- a/tfcrypt.c
+++ b/tfcrypt.c
@@ -328,13 +328,25 @@ int main(int argc, char **argv)
                                                s += 5;
                                                maxkeylen = tfc_humanfsize(s, &stoi);
                                                if (!str_empty(stoi)) {
-                                                       maxkeylen = (size_t)tfc_fnamesize(s, YES);
-                                                       maxkeylen = (size_t)tfc_modifysize((tfc_fsize)maxkeylen, strchr(s, ':'));
+                                                       maxkeylen = tfc_fnamesize(s, YES);
+                                                       maxkeylen = tfc_modifysize(maxkeylen, strchr(s, ':'));
                                                        if (maxkeylen == NOSIZE)
                                                                xerror(NO, YES, YES,
                                                                "%s: invalid key length value", s);
                                                }
-                                               else maxkeylen = (size_t)tfc_modifysize((tfc_fsize)maxkeylen, strchr(s, ':'));
+                                               else maxkeylen = tfc_modifysize(maxkeylen, strchr(s, ':'));
+                                       }
+                                       else if (!strncmp(s, "okey", 4) && *(s+4) == '=') {
+                                               s += 5;
+                                               keyoffset = tfc_humanfsize(s, &stoi);
+                                               if (!str_empty(stoi)) {
+                                                       keyoffset = tfc_fnamesize(s, YES);
+                                                       keyoffset = tfc_modifysize(keyoffset, strchr(s, ':'));
+                                                       if (keyoffset == NOFSIZE)
+                                                               xerror(NO, YES, YES,
+                                                               "%s: invalid key offset value", s);
+                                               }
+                                               else keyoffset = tfc_modifysize(keyoffset, strchr(s, ':'));
                                        }
                                        else if (!strncmp(s, "xctr", 4) && *(s+4) == '=') {
                                                s += 5;
@@ -814,7 +826,7 @@ _pwdagain:  memset(&getps, 0, sizeof(struct getpasswd_state));
                memset(pwdagain, 0, sizeof(pwdagain));
        }
        else {
-               if (skeinfd(key, TFC_KEY_BITS, mackey_opt ? mackey : NULL, kfd, maxkeylen) != YES)
+               if (skeinfd(key, TFC_KEY_BITS, mackey_opt ? mackey : NULL, kfd, keyoffset, maxkeylen) != YES)
                        xerror(NO, NO, YES, "hashing key");
        }