importd: support SUSE style checksums (#5206)

In order to verify a pulled container or disk image, importd only supports
SHA256SUMS files with the detached signature in SHA256SUMS.gpg.
SUSE is using an inline signed file with the name of the image itself and the
suffix .sha256 instead.
This commit adds support for this type of signature files.

It is first attempted to pull the .sha256 file.
If this fails with error 404, the SHA256SUMS and SHA256SUMS.gpg files are
pulled and used for verification.

5 files changed, 103 insertions, 12 deletions

diff --git a/src/import/pull-common.c b/src/import/pull-common.c
index 62a9195cc4..4c745288f5 100644
--- a/src/import/pull-common.c
+++ b/src/import/pull-common.c
@@ -275,6 +275,7 @@ int pull_make_verification_jobs(
 
         _cleanup_(pull_job_unrefp) PullJob *checksum_job = NULL, *signature_job = NULL;
         int r;
+        const char *chksums = NULL;
 
         assert(ret_checksum_job);
         assert(ret_signature_job);
@@ -284,10 +285,16 @@ int pull_make_verification_jobs(
         assert(glue);
 
         if (verify != IMPORT_VERIFY_NO) {
-                _cleanup_free_ char *checksum_url = NULL;
+                _cleanup_free_ char *checksum_url = NULL, *fn = NULL;
 
-                /* Queue job for the SHA256SUMS file for the image */
-                r = import_url_change_last_component(url, "SHA256SUMS", &checksum_url);
+                /* Queue jobs for the checksum file for the image. */
+                r = import_url_last_component(url, &fn);
+                if (r < 0)
+                        return r;
+
+                chksums = strjoina(fn, ".sha256");
+
+                r = import_url_change_last_component(url, chksums, &checksum_url);
                 if (r < 0)
                         return r;
 
@@ -362,6 +369,15 @@ static int verify_one(PullJob *checksum_job, PullJob *job) {
                    line,
                    strlen(line));
 
+        if (!p) {
+                line = strjoina(job->checksum, "  ", fn, "\n");
+
+                p = memmem(checksum_job->payload,
+                        checksum_job->payload_size,
+                        line,
+                        strlen(line));
+        }
+
         if (!p || (p != (char*) checksum_job->payload && p[-1] != '\n')) {
                 log_error("DOWNLOAD INVALID: Checksum of %s file did not checkout, file has been tampered with.", fn);
                 return -EBADMSG;
@@ -416,6 +432,9 @@ int pull_verify(PullJob *main_job,
         if (!signature_job)
                 return 0;
 
+        if (checksum_job->style == VERIFICATION_PER_FILE)
+                signature_job = checksum_job;
+
         assert(signature_job->state == PULL_JOB_DONE);
 
         if (!signature_job->payload || signature_job->payload_size <= 0) {
@@ -507,9 +526,11 @@ int pull_verify(PullJob *main_job,
                         cmd[k++] = "--keyring=" VENDOR_KEYRING_PATH;
 
                 cmd[k++] = "--verify";
-                cmd[k++] = sig_file_path;
-                cmd[k++] = "-";
-                cmd[k++] = NULL;
+                if (checksum_job->style == VERIFICATION_PER_DIRECTORY) {
+                        cmd[k++] = sig_file_path;
+                        cmd[k++] = "-";
+                        cmd[k++] = NULL;
+                }
 
                 stdio_unset_cloexec();
 
diff --git a/src/import/pull-job.c b/src/import/pull-job.c
index 70aaa5c291..8eabb09eed 100644
--- a/src/import/pull-job.c
+++ b/src/import/pull-job.c
@@ -29,6 +29,8 @@
 #include "string-util.h"
 #include "strv.h"
 #include "xattr-util.h"
+#include "pull-common.h"
+#include "import-util.h"
 
 PullJob* pull_job_unref(PullJob *j) {
         if (!j)
@@ -73,6 +75,33 @@ static void pull_job_finish(PullJob *j, int ret) {
                 j->on_finished(j);
 }
 
+static int pull_job_restart(PullJob *j) {
+        int r;
+        char *chksum_url = NULL;
+
+        r = import_url_change_last_component(j->url, "SHA256SUMS", &chksum_url);
+        if (r < 0)
+                return r;
+
+        free(j->url);
+        free(j->payload);
+        j->url = chksum_url;
+        j->state = PULL_JOB_INIT;
+        j->payload = NULL;
+        j->payload_size = 0;
+        j->payload_allocated = 0;
+        j->written_compressed = 0;
+        j->written_uncompressed = 0;
+        j->written_since_last_grow = 0;
+
+        r = pull_job_begin(j);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+
 void pull_job_curl_on_finished(CurlGlue *g, CURL *curl, CURLcode result) {
         PullJob *j = NULL;
         CURLcode code;
@@ -102,6 +131,26 @@ void pull_job_curl_on_finished(CurlGlue *g, CURL *curl, CURLcode result) {
                 r = 0;
                 goto finish;
         } else if (status >= 300) {
+                if (status == 404 && j->style == VERIFICATION_PER_FILE) {
+
+                        /* retry pull job with SHA256SUMS file */
+                        r = pull_job_restart(j);
+                        if (r < 0)
+                                goto finish;
+
+                        code = curl_easy_getinfo(j->curl, CURLINFO_RESPONSE_CODE, &status);
+                        if (code != CURLE_OK) {
+                                log_error("Failed to retrieve response code: %s", curl_easy_strerror(code));
+                                r = -EIO;
+                                goto finish;
+                        }
+
+                        if (status == 0) {
+                                j->style = VERIFICATION_PER_DIRECTORY;
+                                return;
+                        }
+                }
+
                 log_error("HTTP request to %s failed with code %li.", j->url, status);
                 r = -EIO;
                 goto finish;
@@ -528,6 +577,7 @@ int pull_job_new(PullJob **ret, const char *url, CurlGlue *glue, void *userdata)
         j->content_length = (uint64_t) -1;
         j->start_usec = now(CLOCK_MONOTONIC);
         j->compressed_max = j->uncompressed_max = 64LLU * 1024LLU * 1024LLU * 1024LLU; /* 64GB safety limit */
+        j->style = VERIFICATION_STYLE_UNSET;
 
         j->url = strdup(url);
         if (!j->url)
diff --git a/src/import/pull-job.h b/src/import/pull-job.h
index 3a152a50e3..412b66cf22 100644
--- a/src/import/pull-job.h
+++ b/src/import/pull-job.h
@@ -42,6 +42,12 @@ typedef enum PullJobState {
         _PULL_JOB_STATE_INVALID = -1,
 } PullJobState;
 
+typedef enum VerificationStyle {
+        VERIFICATION_STYLE_UNSET,
+        VERIFICATION_PER_FILE,        /* SuSE-style ".sha256" files with inline signature */
+        VERIFICATION_PER_DIRECTORY,   /* Ubuntu-style SHA256SUM files with detach SHA256SUM.gpg signatures */
+} VerificationStyle;
+
 #define PULL_JOB_IS_COMPLETE(j) (IN_SET((j)->state, PULL_JOB_DONE, PULL_JOB_FAILED))
 
 struct PullJob {
@@ -94,6 +100,8 @@ struct PullJob {
 
         bool grow_machine_directory;
         uint64_t written_since_last_grow;
+
+        VerificationStyle style;
 };
 
 int pull_job_new(PullJob **job, const char *url, CurlGlue *glue, void *userdata);
diff --git a/src/import/pull-raw.c b/src/import/pull-raw.c
index 60a769e944..fd2e472f09 100644
--- a/src/import/pull-raw.c
+++ b/src/import/pull-raw.c
@@ -478,11 +478,9 @@ static void raw_pull_job_on_finished(PullJob *j) {
         } else if (j == i->settings_job) {
                 if (j->error != 0)
                         log_info_errno(j->error, "Settings file could not be retrieved, proceeding without.");
-        } else if (j->error != 0) {
+        } else if (j->error != 0 && j != i->signature_job) {
                 if (j == i->checksum_job)
                         log_error_errno(j->error, "Failed to retrieve SHA256 checksum, cannot verify. (Try --verify=no?)");
-                else if (j == i->signature_job)
-                        log_error_errno(j->error, "Failed to retrieve signature file, cannot verify. (Try --verify=no?)");
                 else
                         log_error_errno(j->error, "Failed to retrieve image file. (Wrong URL?)");
 
@@ -500,6 +498,13 @@ static void raw_pull_job_on_finished(PullJob *j) {
         if (!raw_pull_is_done(i))
                 return;
 
+        if (i->checksum_job->style == VERIFICATION_PER_DIRECTORY && i->signature_job->error != 0) {
+                log_error_errno(j->error, "Failed to retrieve signature file, cannot verify. (Try --verify=no?)");
+
+                r = i->signature_job->error;
+                goto finish;
+        }
+
         if (i->roothash_job)
                 i->roothash_job->disk_fd = safe_close(i->roothash_job->disk_fd);
         if (i->settings_job)
@@ -744,6 +749,7 @@ int raw_pull_start(
 
         if (i->checksum_job) {
                 i->checksum_job->on_progress = raw_pull_job_on_progress;
+                i->checksum_job->style = VERIFICATION_PER_FILE;
 
                 r = pull_job_begin(i->checksum_job);
                 if (r < 0)
diff --git a/src/import/pull-tar.c b/src/import/pull-tar.c
index 91833d6174..d4b599ba95 100644
--- a/src/import/pull-tar.c
+++ b/src/import/pull-tar.c
@@ -298,11 +298,9 @@ static void tar_pull_job_on_finished(PullJob *j) {
         if (j == i->settings_job) {
                 if (j->error != 0)
                         log_info_errno(j->error, "Settings file could not be retrieved, proceeding without.");
-        } else if (j->error != 0) {
+        } else if (j->error != 0 && j != i->signature_job) {
                 if (j == i->checksum_job)
                         log_error_errno(j->error, "Failed to retrieve SHA256 checksum, cannot verify. (Try --verify=no?)");
-                else if (j == i->signature_job)
-                        log_error_errno(j->error, "Failed to retrieve signature file, cannot verify. (Try --verify=no?)");
                 else
                         log_error_errno(j->error, "Failed to retrieve image file. (Wrong URL?)");
 
@@ -317,6 +315,13 @@ static void tar_pull_job_on_finished(PullJob *j) {
         if (!tar_pull_is_done(i))
                 return;
 
+        if (i->checksum_job->style == VERIFICATION_PER_DIRECTORY && i->signature_job->error != 0) {
+                log_error_errno(j->error, "Failed to retrieve signature file, cannot verify. (Try --verify=no?)");
+
+                r = i->signature_job->error;
+                goto finish;
+        }
+
         i->tar_job->disk_fd = safe_close(i->tar_job->disk_fd);
         if (i->settings_job)
                 i->settings_job->disk_fd = safe_close(i->settings_job->disk_fd);
@@ -547,6 +552,7 @@ int tar_pull_start(
 
         if (i->checksum_job) {
                 i->checksum_job->on_progress = tar_pull_job_on_progress;
+                i->checksum_job->style = VERIFICATION_PER_FILE;
 
                 r = pull_job_begin(i->checksum_job);
                 if (r < 0)