From f6373b7dd7a2b8a8e38c289f289728d289382f29 Mon Sep 17 00:00:00 2001

From: Harald Hoyer <harald@redhat.com>

Date: Mon, 1 Jun 2015 17:26:27 +0200

Subject: [PATCH 4/4] cryptsetup: craft a unique ID with the source device

If cryptsetup is called with a source device as argv[3], then craft the

ID for the password agent with a unique device path.

If possible "/dev/block/<maj>:<min>" is used, otherwise the original

argv[3] is used.

This enables password agents like petera [1] to provide a password

according to the source device. The original ID did not carry enough

information and was more targeted for a human readable string, which

is specified in the "Message" field anyway.

With this patch the ID of the ask.XXX ini file looks like this:

ID=cryptsetup:/dev/block/<maj>:<min>

[1] https://github.com/npmccallum/petera

---

 src/cryptsetup/cryptsetup.c | 90 +++++++++++++++++++++++++++++----------------

 1 file changed, 58 insertions(+), 32 deletions(-)

diff --git a/src/cryptsetup/cryptsetup.c b/src/cryptsetup/cryptsetup.c

index a5018f1..5c6c7c0 100644

--- a/src/cryptsetup/cryptsetup.c

+++ b/src/cryptsetup/cryptsetup.c

@@ -238,6 +238,23 @@ static void log_glue(int level, const char *msg, void *usrptr) {

         log_debug("%s", msg);

 }

+static int disk_major_minor(const char *path, char **ret) {

+        struct stat st;

+

+        assert(path);

+

+        if (stat(path, &st) < 0)

+                return -errno;

+

+        if (!S_ISBLK(st.st_mode))

+                return -EINVAL;

+

+        if (asprintf(ret, "/dev/block/%d:%d", major(st.st_rdev), minor(st.st_rdev)) < 0)

+                return -errno;

+

+        return 0;

+}

+

 static char* disk_description(const char *path) {

         static const char name_fields[] =

@@ -295,20 +312,55 @@ static char *disk_mount_point(const char *label) {

         return NULL;

 }

-static int get_password(const char *name, usec_t until, bool accept_cached, char ***passwords) {

-        int r;

+static int get_password(const char *vol, const char *src, usec_t until, bool accept_cached, char ***passwords) {

+        int r = 0;

         char **p;

         _cleanup_free_ char *text = NULL;

         _cleanup_free_ char *escaped_name = NULL;

         char *id;

+        const char *name = NULL;

+        _cleanup_free_ char *description = NULL, *name_buffer = NULL,

+                *mount_point = NULL, *maj_min = NULL;

-        assert(name);

+        assert(vol);

+        assert(src);

         assert(passwords);

+        description = disk_description(src);

+        mount_point = disk_mount_point(vol);

+

+        if (description && streq(vol, description)) {

+                /* If the description string is simply the

+                 * volume name, then let's not show this

+                 * twice */

+                free(description);

+                description = NULL;

+        }

+

+        if (mount_point && description)

+                r = asprintf(&name_buffer, "%s (%s) on %s", description, vol, mount_point);

+        else if (mount_point)

+                r = asprintf(&name_buffer, "%s on %s", vol, mount_point);

+        else if (description)

+                r = asprintf(&name_buffer, "%s (%s)", description, vol);

+

+        if (r < 0)

+                return log_oom();

+

+        name = name_buffer ? name_buffer : vol;

+

         if (asprintf(&text, "Please enter passphrase for disk %s!", name) < 0)

                 return log_oom();

-        escaped_name = cescape(name);

+        if (src)

+                (void) disk_major_minor(src, &maj_min);

+

+        if (maj_min) {

+                escaped_name = maj_min;

+                maj_min = NULL;

+        } else

+                escaped_name = cescape(name);

+

         if (!escaped_name)

                 return log_oom();

@@ -552,8 +604,7 @@ int main(int argc, char *argv[]) {

                 unsigned tries;

                 usec_t until;

                 crypt_status_info status;

-                const char *key_file = NULL, *name = NULL;

-                _cleanup_free_ char *description = NULL, *name_buffer = NULL, *mount_point = NULL;

+                const char *key_file = NULL;

                 /* Arguments: systemd-cryptsetup attach VOLUME SOURCE-DEVICE [PASSWORD] [OPTIONS] */

@@ -581,31 +632,6 @@ int main(int argc, char *argv[]) {

                 /* A delicious drop of snake oil */

                 mlockall(MCL_FUTURE);

-                description = disk_description(argv[3]);

-                mount_point = disk_mount_point(argv[2]);

-

-                if (description && streq(argv[2], description)) {

-                        /* If the description string is simply the

-                         * volume name, then let's not show this

-                         * twice */

-                        free(description);

-                        description = NULL;

-                }

-

-                k = 0;

-                if (mount_point && description)

-                        k = asprintf(&name_buffer, "%s (%s) on %s", description, argv[2], mount_point);

-                else if (mount_point)

-                        k = asprintf(&name_buffer, "%s on %s", argv[2], mount_point);

-                else if (description)

-                        k = asprintf(&name_buffer, "%s (%s)", description, argv[2]);

-

-                if (k < 0) {

-                        log_oom();

-                        goto finish;

-                }

-                name = name_buffer ? name_buffer : argv[2];

-

                 if (arg_header) {

                         log_debug("LUKS header: %s", arg_header);

                         k = crypt_init(&cd, arg_header);

@@ -652,7 +678,7 @@ int main(int argc, char *argv[]) {

                         _cleanup_strv_free_ char **passwords = NULL;

                         if (!key_file) {

-                                k = get_password(name, until, tries == 0 && !arg_verify, &passwords);

+                                k = get_password(argv[2], argv[3], until, tries == 0 && !arg_verify, &passwords);

                                 if (k == -EAGAIN)

                                         continue;

                                 else if (k < 0)

-- 

2.4.1