From: David Härdeman <david@hardeman.nu>
Date: Tue, 25 Mar 2014 10:05:28 +0000 (+0100)
Subject: Fix keysize handling in cryptsetup (bits vs. bytes)
X-Git-Tag: v213~320
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=6131a78b4d247618715e042e14ad682f678d3b32;hp=9fa1de965a0954dcb6d855ebe0513077515a0daa;ds=sidebyside

Fix keysize handling in cryptsetup (bits vs. bytes)

The command line key-size is in bits but the libcryptsetup API expects bytes.

Note that the modulo 8 check is in the original cryptsetup binary as well, so
it's no new limitation.

(v2: changed the point at which the /= 8 is performed, rebased, removed tabs)
---

diff --git a/src/cryptsetup/cryptsetup.c b/src/cryptsetup/cryptsetup.c
index a647a94e6..812b32f6c 100644
--- a/src/cryptsetup/cryptsetup.c
+++ b/src/cryptsetup/cryptsetup.c
@@ -88,6 +88,13 @@ static int parse_one_option(const char *option) {
                         return 0;
                 }
 
+                if (arg_key_size % 8) {
+                        log_error("size= not a multiple of 8, ignoring.");
+                        return 0;
+                }
+
+                arg_key_size /= 8;
+
         } else if (startswith(option, "key-slot=")) {
 
                 arg_type = CRYPT_LUKS1;
@@ -414,7 +421,7 @@ static int attach_luks_or_plain(struct crypt_device *cd,
                 /* for CRYPT_PLAIN limit reads
                  * from keyfile to key length, and
                  * ignore keyfile-size */
-                arg_keyfile_size = arg_key_size / 8;
+                arg_keyfile_size = arg_key_size;
 
                 /* In contrast to what the name
                  * crypt_setup() might suggest this
@@ -577,7 +584,7 @@ int main(int argc, char *argv[]) {
                 else
                         until = 0;
 
-                arg_key_size = (arg_key_size > 0 ? arg_key_size : 256);
+                arg_key_size = (arg_key_size > 0 ? arg_key_size : (256 / 8));
 
                 if (key_file) {
                         struct stat st;