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cockpit-certificate-ensure: soften the certificate generation #21069

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cockpit-certificate-ensure: soften the certificate generation #21069

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f53e72f
cockpit-certificate-ensure: fix usage
jmlemetayer Oct 2, 2024
28ef6ab
cockpit-certificate-ensure: soften the certificate generation
jmlemetayer Oct 2, 2024
e44a7b3
cockpit-certificate-helper: force writing of new files on disk
jmlemetayer Oct 2, 2024
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54 changes: 46 additions & 8 deletions src/tls/cockpit-certificate-ensure.c
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Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,9 @@
// We tolerate the deprecated merged cert/key files only for cockpit-tls.
static bool tolerate_merged_cert_key;

// Depending on the mode, some errors are recoverable.
static bool exit_on_error;
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typedef struct
{
char *certificate_filename;
Expand All @@ -66,13 +69,16 @@ typedef struct
char *filename_for_errors;
} CertificateKeyPair;

static void
static int
read_file (const char *filename,
gnutls_datum_t *result)
{
int fd = open (filename, O_RDONLY);
if (fd == -1)
err (EXIT_FAILURE, "open: %s", filename);
{
warn ("open: %s", filename);
return -1;
}

struct stat buf;
if (fstat (fd, &buf) != 0)
Expand All @@ -94,6 +100,7 @@ read_file (const char *filename,
result->data[s] = '\0';

close (fd);
return 0;
}

static void
Expand Down Expand Up @@ -277,12 +284,20 @@ certificate_and_key_split (CertificateKeyPair *self)
return false;
}

static void
static int
certificate_and_key_read (CertificateKeyPair *self,
const char *certificate_filename)
{
self->certificate_filename = strdupx (certificate_filename);
read_file (self->certificate_filename, &self->certificate);

if (read_file (self->certificate_filename, &self->certificate) < 0)
return -1;

if (self->certificate.size == 0)
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This feels arbitrary and too brittle. If the concern is short writes after a power loss, then "0 bytes" feels like a "lucky unlucky" case.

The normal way to avoid that is to write the file with a temp name, fsync() it, and then rename it to the final name. Your third commit aims at that, I'll comment on that separately.

On the reading side, the gnutls functions to parse the certificate should already fail (in certificate_and_key_parse_to_creds()) if the certificate is empty, or if the file is truncated, so this check here ought to be redundant?

{
warnx ("empty: %s", self->certificate_filename);
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Likewise.

return -1;
}

if (certificate_and_key_split (self))
{
Expand All @@ -298,13 +313,23 @@ certificate_and_key_read (CertificateKeyPair *self,
else
{
self->key_filename = cockpit_certificate_key_path (self->certificate_filename);
read_file (self->key_filename, &self->key);

if (read_file (self->key_filename, &self->key) < 0)
return -1;

if (self->key.size == 0)
{
warnx ("empty: %s", self->key_filename);
return -1;
}
}

if (self->key_filename)
asprintfx (&self->filename_for_errors, "%s/.key", self->certificate_filename);
else
self->filename_for_errors = strdupx (self->certificate_filename);

return 0;
}

static gnutls_certificate_credentials_t
Expand Down Expand Up @@ -343,7 +368,16 @@ cockpit_certificate_find (CertificateKeyPair *result,
return false;
}

certificate_and_key_read (result, certificate_filename);
if (certificate_and_key_read (result, certificate_filename) < 0)
{
if (verbose)
printf ("Unable to read certificate file or key file\n");
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if (exit_on_error)
exit (EXIT_FAILURE);

return false;
}

gnutls_certificate_credentials_t creds = certificate_and_key_parse_to_creds (result);

Expand Down Expand Up @@ -387,7 +421,8 @@ cockpit_certificate_selfsign (CertificateKeyPair *result)
errx (EXIT_FAILURE, "%s exited with non-zero status %d",
COCKPIT_CERTIFICATE_HELPER, WEXITSTATUS (status));

certificate_and_key_read (result, COCKPIT_SELFSIGNED_PATH);
if (certificate_and_key_read (result, COCKPIT_SELFSIGNED_PATH) < 0)
exit (EXIT_FAILURE);

/* We just generated this ourselves, so we don't bother to check it
* for validity.
Expand All @@ -408,7 +443,10 @@ main (int argc, char **argv)
else if (argc == 2 && strcmp (argv[1], "--for-cockpit-tls") == 0)
for_cockpit_tls = true;
else
errx (EXIT_FAILURE, "usage: %s [--check]", argv[0]);
errx (EXIT_FAILURE, "usage: %s [--check | --for-cockpit-tls]", argv[0]);
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if (check)
exit_on_error = true;

if (for_cockpit_tls)
tolerate_merged_cert_key = true;
Expand Down
3 changes: 3 additions & 0 deletions src/tls/cockpit-certificate-helper.in
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Expand Up @@ -81,6 +81,9 @@ cmd_selfsign() {
test ! -e "${CA_FILE}" || install_cert "${CA_FILE}"
install_cert "${CERTFILE}"
install_key "${KEYFILE}"

# Force writing of new files on disk.
sync
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}

cmd_ipa_request() {
Expand Down
4 changes: 2 additions & 2 deletions src/tls/test-cockpit-certificate-ensure.c
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Expand Up @@ -314,7 +314,7 @@ static const TestCase case_bad_file = {
static const TestCase case_bad_file2 = {
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The tests need to be extended to cover the cases you mention (empty/truncated file and such). But let's sort out the above questions first.

.files = bad_files2,

.check_stdout = "",
.check_stdout = "Unable to read*",
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This is a symptom of the above "should go to stderr" comment. The stderr check already covers having a more precise error message.

.check_stderr = "*open*mock-server.key*No such file*",
.check_exit = EXIT_FAILURE,

Expand All @@ -334,7 +334,7 @@ static const TestCase case_invalid1 = {
static const TestCase case_invalid2 = {
.files = invalid_files2,

.check_stdout = "",
.check_stdout = "Unable to read*",
.check_stderr = "*open*mock-server.key*No such file*",
.check_exit = EXIT_FAILURE,

Expand Down