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From 6c45bdd261e027ea78eabb81feaa70f3774bcf2f Mon Sep 17 00:00:00 2001
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From: Harald Hoyer <harald@redhat.com>
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Date: Mon, 1 Jun 2015 17:26:27 +0200
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Subject: [PATCH] cryptsetup: craft a unique ID with the source device
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If cryptsetup is called with a source device as argv[3], then craft the
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ID for the password agent with a unique device path.
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If possible "/dev/block/<maj>:<min>" is used, otherwise the original
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argv[3] is used.
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This enables password agents like petera [1] to provide a password
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according to the source device. The original ID did not carry enough
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information and was more targeted for a human readable string, which
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is specified in the "Message" field anyway.
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With this patch the ID of the ask.XXX ini file looks like this:
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ID=cryptsetup:/dev/block/<maj>:<min>
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[1] https://github.com/npmccallum/petera
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Cherry-picked from: e51b9486d1b59e72c293028fed1384f4e4ef09aa
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Resolves: #1226333
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---
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 src/cryptsetup/cryptsetup.c | 90 +++++++++++++++++++++++++++++----------------
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 1 file changed, 58 insertions(+), 32 deletions(-)
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diff --git a/src/cryptsetup/cryptsetup.c b/src/cryptsetup/cryptsetup.c
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index 3f613d9b6..5dedb073e 100644
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--- a/src/cryptsetup/cryptsetup.c
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+++ b/src/cryptsetup/cryptsetup.c
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@@ -217,6 +217,23 @@ static void log_glue(int level, const char *msg, void *usrptr) {
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         log_debug("%s", msg);
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 }
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+static int disk_major_minor(const char *path, char **ret) {
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+        struct stat st;
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+
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+        assert(path);
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+
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+        if (stat(path, &st) < 0)
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+                return -errno;
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+
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+        if (!S_ISBLK(st.st_mode))
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+                return -EINVAL;
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+
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+        if (asprintf(ret, "/dev/block/%d:%d", major(st.st_rdev), minor(st.st_rdev)) < 0)
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+                return -errno;
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+
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+        return 0;
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+}
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+
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 static char* disk_description(const char *path) {
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         static const char name_fields[] =
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@@ -278,20 +295,55 @@ static char *disk_mount_point(const char *label) {
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         return NULL;
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 }
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-static int get_password(const char *name, usec_t until, bool accept_cached, char ***passwords) {
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-        int r;
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+static int get_password(const char *vol, const char *src, usec_t until, bool accept_cached, char ***passwords) {
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+        int r = 0;
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         char **p;
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         _cleanup_free_ char *text = NULL;
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         _cleanup_free_ char *escaped_name = NULL;
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         char *id;
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+        const char *name = NULL;
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+        _cleanup_free_ char *description = NULL, *name_buffer = NULL,
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+                *mount_point = NULL, *maj_min = NULL;
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-        assert(name);
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+        assert(vol);
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+        assert(src);
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         assert(passwords);
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+        description = disk_description(src);
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+        mount_point = disk_mount_point(vol);
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+
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+        if (description && streq(vol, description)) {
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+                /* If the description string is simply the
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+                 * volume name, then let's not show this
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+                 * twice */
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+                free(description);
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+                description = NULL;
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+        }
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+
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+        if (mount_point && description)
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+                r = asprintf(&name_buffer, "%s (%s) on %s", description, vol, mount_point);
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+        else if (mount_point)
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+                r = asprintf(&name_buffer, "%s on %s", vol, mount_point);
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+        else if (description)
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+                r = asprintf(&name_buffer, "%s (%s)", description, vol);
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+
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+        if (r < 0)
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+                return log_oom();
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+
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+        name = name_buffer ? name_buffer : vol;
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+
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         if (asprintf(&text, "Please enter passphrase for disk %s!", name) < 0)
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                 return log_oom();
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-        escaped_name = cescape(name);
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+        if (src)
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+                (void) disk_major_minor(src, &maj_min);
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+
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+        if (maj_min) {
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+                escaped_name = maj_min;
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+                maj_min = NULL;
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+        } else
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+                escaped_name = cescape(name);
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+
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         if (!escaped_name)
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                 return log_oom();
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@@ -532,8 +584,7 @@ int main(int argc, char *argv[]) {
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                 unsigned tries;
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                 usec_t until;
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                 crypt_status_info status;
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-                const char *key_file = NULL, *name = NULL;
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-                _cleanup_free_ char *description = NULL, *name_buffer = NULL, *mount_point = NULL;
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+                const char *key_file = NULL;
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                 /* Arguments: systemd-cryptsetup attach VOLUME SOURCE-DEVICE [PASSWORD] [OPTIONS] */
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@@ -561,31 +612,6 @@ int main(int argc, char *argv[]) {
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                 /* A delicious drop of snake oil */
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                 mlockall(MCL_FUTURE);
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-                description = disk_description(argv[3]);
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-                mount_point = disk_mount_point(argv[2]);
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-
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-                if (description && streq(argv[2], description)) {
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-                        /* If the description string is simply the
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-                         * volume name, then let's not show this
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-                         * twice */
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-                        free(description);
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-                        description = NULL;
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-                }
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-
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-                k = 0;
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-                if (mount_point && description)
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-                        k = asprintf(&name_buffer, "%s (%s) on %s", description, argv[2], mount_point);
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-                else if (mount_point)
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-                        k = asprintf(&name_buffer, "%s on %s", argv[2], mount_point);
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-                else if (description)
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-                        k = asprintf(&name_buffer, "%s (%s)", description, argv[2]);
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-
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-                if (k < 0) {
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-                        log_oom();
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-                        goto finish;
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-                }
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-                name = name_buffer ? name_buffer : argv[2];
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-
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                 if (arg_header) {
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                         log_debug("LUKS header: %s", arg_header);
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                         k = crypt_init(&cd, arg_header);
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@@ -632,7 +658,7 @@ int main(int argc, char *argv[]) {
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                         _cleanup_strv_free_ char **passwords = NULL;
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                         if (!key_file) {
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-                                k = get_password(name, until, tries == 0 && !arg_verify, &passwords);
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+                                k = get_password(argv[2], argv[3], until, tries == 0 && !arg_verify, &passwords);
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                                 if (k == -EAGAIN)
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                                         continue;
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                                 else if (k < 0)