mirror of
git://git.gnupg.org/gnupg.git
synced 2025-07-02 22:46:30 +02:00
* command-ssh.c (get_passphrase): Removed.
(ssh_identity_register): Partly rewritten. (open_control_file, search_control_file, add_control_entry): New. (ssh_handler_request_identities): Return only files listed in our control file. * findkey.c (unprotect): Check for allocation error. * agent.h (opt): Add fields to record the startup terminal settings. * gpg-agent.c (main): Record them and do not force keep display with --enable-ssh-support. * command-ssh.c (start_command_handler_ssh): Use them here. * gpg-agent.c: Renamed option --ssh-support to --enable-ssh-support. * command.c (cmd_readkey): New. (register_commands): Register new command "READKEY". * command-ssh.c (ssh_request_process): Improved logging. * findkey.c (agent_write_private_key): Always use plain open. Don't depend on an umask for permissions. (agent_key_from_file): Factored file reading code out to .. (read_key_file): .. new function. (agent_public_key_from_file): New.
This commit is contained in:
Werner Koch
parent
cf8f6d3cef
commit
4e5bf2fd93
9 changed files with 691 additions and 150 deletions
|
|
@ -23,13 +23,14 @@
|
|||
|
||||
#include <config.h>
|
||||
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
#include <errno.h>
|
||||
#include <sys/types.h>
|
||||
#include <sys/stat.h>
|
||||
#include <dirent.h>
|
||||
#include <stdio.h>
|
||||
#include <assert.h>
|
||||
|
||||
#include "agent.h"
|
||||
|
||||
|
|
@ -63,7 +64,22 @@
|
|||
#define SSH_DSA_SIGNATURE_ELEMS 2
|
||||
#define SPEC_FLAG_USE_PKCS1V2 (1 << 0)
|
||||
|
||||
|
||||
|
||||
/* The blurb we put into the header of a newly created control file. */
|
||||
static const char sshcontrolblurb[] =
|
||||
"# List of allowed ssh keys. Only keys present in this file are used\n"
|
||||
"# in the SSH protocol. The ssh-add tool may add new entries to this\n"
|
||||
"# file to enable them; you may also add them manually. Comment\n"
|
||||
"# lines, like this one, as well as empty lines are ignored. Lines do\n"
|
||||
"# have a certain length limit but this is not serious limitation as\n"
|
||||
"# the format of the entries is fixed and checked by gpg-agent. A\n"
|
||||
"# non-comment line starts with optional white spaces, followed by the\n"
|
||||
"# keygrip of the key given as 40 hex digits, optionally followed by a\n"
|
||||
"# the caching TTL in seconds and another optional field for arbitrary\n"
|
||||
"# flags. Prepend the keygrip with an '!' mark to disable it.\n"
|
||||
"\n";
|
||||
|
||||
|
||||
|
||||
/* Macros. */
|
||||
|
||||
|
|
@ -626,6 +642,155 @@ file_to_buffer (const char *filename, unsigned char **buffer, size_t *buffer_n)
|
|||
}
|
||||
|
||||
|
||||
|
||||
|
||||
/* Open the ssh control file and create it if not available. With
|
||||
APPEND passed as true the file will be opened in append mode,
|
||||
otherwise in read only mode. On success a file pointer is stored
|
||||
at the address of R_FP. */
|
||||
static gpg_error_t
|
||||
open_control_file (FILE **r_fp, int append)
|
||||
{
|
||||
gpg_error_t err;
|
||||
char *fname;
|
||||
FILE *fp;
|
||||
|
||||
/* Note: As soon as we start to use non blocking functions here
|
||||
(i.e. where Pth might switch threads) we need to employ a
|
||||
mutex. */
|
||||
*r_fp = NULL;
|
||||
fname = make_filename (opt.homedir, "sshcontrol.txt", NULL);
|
||||
fp = fopen (fname, append? "a+":"r");
|
||||
if (!fp && errno == ENOENT)
|
||||
{
|
||||
/* Fixme: "x" is a GNU extension. We might want to use the es_
|
||||
functions here. */
|
||||
fp = fopen (fname, "wx");
|
||||
if (!fp)
|
||||
{
|
||||
err = gpg_error (gpg_err_code_from_errno (errno));
|
||||
log_error (_("can't create `%s': %s\n"), fname, gpg_strerror (err));
|
||||
xfree (fname);
|
||||
return err;
|
||||
}
|
||||
fputs (sshcontrolblurb, fp);
|
||||
fclose (fp);
|
||||
fp = fopen (fname, append? "a+":"r");
|
||||
}
|
||||
|
||||
if (!fp)
|
||||
{
|
||||
err = gpg_error (gpg_err_code_from_errno (errno));
|
||||
log_error (_("can't open `%s': %s\n"), fname, gpg_strerror (err));
|
||||
xfree (fname);
|
||||
return err;
|
||||
}
|
||||
|
||||
*r_fp = fp;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
/* Search the file at stream FP from the beginning until a matching
|
||||
HEXGRIP is found; return success in this case and store true at
|
||||
DISABLED if the found key has been disabled. */
|
||||
static gpg_error_t
|
||||
search_control_file (FILE *fp, const char *hexgrip, int *disabled)
|
||||
{
|
||||
int c, i;
|
||||
char *p, line[256];
|
||||
|
||||
assert (strlen (hexgrip) == 40 );
|
||||
|
||||
rewind (fp);
|
||||
*disabled = 0;
|
||||
next_line:
|
||||
do
|
||||
{
|
||||
if (!fgets (line, DIM(line)-1, fp) )
|
||||
{
|
||||
if (feof (fp))
|
||||
return gpg_error (GPG_ERR_EOF);
|
||||
return gpg_error (gpg_err_code_from_errno (errno));
|
||||
}
|
||||
|
||||
if (!*line || line[strlen(line)-1] != '\n')
|
||||
{
|
||||
/* Eat until end of line */
|
||||
while ( (c=getc (fp)) != EOF && c != '\n')
|
||||
;
|
||||
return gpg_error (*line? GPG_ERR_LINE_TOO_LONG
|
||||
: GPG_ERR_INCOMPLETE_LINE);
|
||||
}
|
||||
|
||||
/* Allow for empty lines and spaces */
|
||||
for (p=line; spacep (p); p++)
|
||||
;
|
||||
}
|
||||
while (!*p || *p == '\n' || *p == '#');
|
||||
|
||||
*disabled = 0;
|
||||
if (*p == '!')
|
||||
{
|
||||
*disabled = 1;
|
||||
for (p++; spacep (p); p++)
|
||||
;
|
||||
}
|
||||
|
||||
for (i=0; hexdigitp (p) && i < 40; p++, i++)
|
||||
if (hexgrip[i] != (*p >= 'a'? (*p & 0xdf): *p))
|
||||
goto next_line;
|
||||
if (i != 40 || !(spacep (p) || *p == '\n'))
|
||||
{
|
||||
log_error ("invalid formatted line in ssh control file\n");
|
||||
return gpg_error (GPG_ERR_BAD_DATA);
|
||||
}
|
||||
|
||||
/* Fixme: Get TTL and flags. */
|
||||
|
||||
return 0; /* Okay: found it. */
|
||||
}
|
||||
|
||||
|
||||
|
||||
/* Add an entry to the control file to mark the key with the keygrip
|
||||
HEXGRIP as usable for SSH; i.e. it will be returned when ssh asks
|
||||
for it. This function is in general used to add a key received
|
||||
through the ssh-add function. We can assume that the user wants to
|
||||
allow ssh using this key. */
|
||||
static gpg_error_t
|
||||
add_control_entry (ctrl_t ctrl, const char *hexgrip, int ttl)
|
||||
{
|
||||
gpg_error_t err;
|
||||
FILE *fp;
|
||||
int disabled;
|
||||
|
||||
err = open_control_file (&fp, 1);
|
||||
if (err)
|
||||
return err;
|
||||
|
||||
err = search_control_file (fp, hexgrip, &disabled);
|
||||
if (err && gpg_err_code(err) == GPG_ERR_EOF)
|
||||
{
|
||||
struct tm *tp;
|
||||
time_t atime = time (NULL);
|
||||
|
||||
/* Not yet in the file - add it. Becuase the file has been
|
||||
opened in append mode, we simply need to write to it. */
|
||||
tp = localtime (&atime);
|
||||
fprintf (fp, "# Key added on %04d-%02d-%02d %02d:%02d:%02d\n%s %d\n",
|
||||
1900+tp->tm_year, tp->tm_mon+1, tp->tm_mday,
|
||||
tp->tm_hour, tp->tm_min, tp->tm_sec,
|
||||
hexgrip, ttl);
|
||||
|
||||
}
|
||||
fclose (fp);
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
/*
|
||||
|
|
@ -1377,6 +1542,7 @@ ssh_handler_request_identities (ctrl_t ctrl,
|
|||
gpg_error_t err;
|
||||
gpg_error_t ret_err;
|
||||
int ret;
|
||||
FILE *ctrl_fp = NULL;
|
||||
|
||||
/* Prepare buffer stream. */
|
||||
|
||||
|
|
@ -1427,6 +1593,19 @@ ssh_handler_request_identities (ctrl_t ctrl,
|
|||
|
||||
/* FIXME: make sure that buffer gets deallocated properly. */
|
||||
|
||||
/* Fixme: We should better iterate over the control file and check
|
||||
whether the key file is there. This is better in resepct to
|
||||
performance if tehre are a lot of key sin our key storage. */
|
||||
|
||||
err = open_control_file (&ctrl_fp, 0);
|
||||
if (err)
|
||||
goto out;
|
||||
|
||||
#warning Really need to fix this fixme.
|
||||
/*
|
||||
FIXME: First check whether a key is currently available in the card reader - this should be allowed even without being listed in sshcontrol.txt.
|
||||
*/
|
||||
|
||||
while (1)
|
||||
{
|
||||
dir_entry = readdir (dir);
|
||||
|
|
@ -1435,6 +1614,19 @@ ssh_handler_request_identities (ctrl_t ctrl,
|
|||
if ((strlen (dir_entry->d_name) == 44)
|
||||
&& (! strncmp (dir_entry->d_name + 40, ".key", 4)))
|
||||
{
|
||||
char hexgrip[41];
|
||||
int disabled;
|
||||
|
||||
/* We do only want to return keys listed in our control
|
||||
file. */
|
||||
strncpy (hexgrip, dir_entry->d_name, 40);
|
||||
hexgrip[40] = 0;
|
||||
if ( strlen (hexgrip) != 40 )
|
||||
continue;
|
||||
if (search_control_file (ctrl_fp, hexgrip, &disabled)
|
||||
|| disabled)
|
||||
continue;
|
||||
|
||||
strncpy (key_path + key_directory_n + 1, dir_entry->d_name, 40);
|
||||
|
||||
/* Read file content. */
|
||||
|
|
@ -1522,6 +1714,9 @@ ssh_handler_request_identities (ctrl_t ctrl,
|
|||
if (dir)
|
||||
closedir (dir);
|
||||
|
||||
if (ctrl_fp)
|
||||
fclose (ctrl_fp);
|
||||
|
||||
free (key_directory);
|
||||
xfree (key_path);
|
||||
xfree (buffer);
|
||||
|
|
@ -1802,43 +1997,6 @@ ssh_handler_sign_request (ctrl_t ctrl, estream_t request, estream_t response)
|
|||
return ret_err;
|
||||
}
|
||||
|
||||
static gpg_error_t
|
||||
get_passphrase (ctrl_t ctrl,
|
||||
const char *description, size_t passphrase_n, char *passphrase)
|
||||
{
|
||||
struct pin_entry_info_s *pi;
|
||||
gpg_error_t err;
|
||||
|
||||
err = 0;
|
||||
pi = gcry_calloc_secure (1, sizeof (*pi) + passphrase_n + 1);
|
||||
if (! pi)
|
||||
{
|
||||
err = gpg_error (GPG_ERR_ENOMEM);
|
||||
goto out;
|
||||
}
|
||||
|
||||
pi->min_digits = 0; /* We want a real passphrase. */
|
||||
pi->max_digits = 8;
|
||||
pi->max_tries = 1;
|
||||
pi->failed_tries = 0;
|
||||
pi->check_cb = NULL;
|
||||
pi->check_cb_arg = NULL;
|
||||
pi->cb_errtext = NULL;
|
||||
pi->max_length = 100;
|
||||
|
||||
err = agent_askpin (ctrl, description, NULL, pi);
|
||||
if (err)
|
||||
goto out;
|
||||
|
||||
memcpy (passphrase, pi->pin, passphrase_n);
|
||||
passphrase[passphrase_n] = 0;
|
||||
|
||||
out:
|
||||
|
||||
xfree (pi);
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
static gpg_error_t
|
||||
ssh_key_extract_comment (gcry_sexp_t key, char **comment)
|
||||
|
|
@ -1929,76 +2087,100 @@ ssh_key_to_buffer (gcry_sexp_t key, const char *passphrase,
|
|||
return err;
|
||||
}
|
||||
|
||||
|
||||
|
||||
/* Store the ssh KEY into our local key storage and protect him after
|
||||
asking for a passphrase. Cache that passphrase. TTL is the
|
||||
maximum caching time for that key. If the key already exists in
|
||||
our key storage, don't do anything. When entering a new key also
|
||||
add an entry to the sshcontrol file. */
|
||||
static gpg_error_t
|
||||
ssh_identity_register (ctrl_t ctrl, gcry_sexp_t key, int ttl)
|
||||
{
|
||||
unsigned char key_grip_raw[21];
|
||||
unsigned char *buffer;
|
||||
unsigned int buffer_n;
|
||||
char passphrase[100];
|
||||
char *description;
|
||||
char key_grip[41];
|
||||
char *comment;
|
||||
gpg_error_t err;
|
||||
unsigned char key_grip_raw[21];
|
||||
char key_grip[41];
|
||||
unsigned char *buffer = NULL;
|
||||
unsigned int buffer_n;
|
||||
char *description = NULL;
|
||||
char *comment = NULL;
|
||||
unsigned int i;
|
||||
int ret;
|
||||
|
||||
description = NULL;
|
||||
comment = NULL;
|
||||
buffer = NULL;
|
||||
struct pin_entry_info_s *pi = NULL;
|
||||
|
||||
err = ssh_key_grip (key, key_grip_raw);
|
||||
if (err)
|
||||
goto out;
|
||||
|
||||
key_grip_raw[sizeof (key_grip_raw) - 1] = 0;
|
||||
ret = agent_key_available (key_grip_raw);
|
||||
if (! ret)
|
||||
goto out;
|
||||
key_grip_raw[sizeof (key_grip_raw) - 1] = 0; /* FIXME: Why?? */
|
||||
|
||||
/* Check whether the key is alread in our key storage. Don't do
|
||||
anything then. */
|
||||
if ( !agent_key_available (key_grip_raw) )
|
||||
goto out; /* Yes, key is available. */
|
||||
|
||||
|
||||
err = ssh_key_extract_comment (key, &comment);
|
||||
if (err)
|
||||
goto out;
|
||||
|
||||
ret = asprintf (&description,
|
||||
"Please provide the passphrase, which should be used "
|
||||
"for protecting the received secret key `%s':",
|
||||
comment ? comment : "");
|
||||
if (ret < 0)
|
||||
if ( asprintf (&description,
|
||||
_("Please enter a passphrase to protect%%0A"
|
||||
"the received secret key%%0A"
|
||||
" %s%%0A"
|
||||
"within gpg-agent's key storage"),
|
||||
comment ? comment : "?") < 0)
|
||||
{
|
||||
err = gpg_err_code_from_errno (errno);
|
||||
err = gpg_error_from_errno (errno);
|
||||
goto out;
|
||||
}
|
||||
|
||||
err = get_passphrase (ctrl, description, sizeof (passphrase), passphrase);
|
||||
|
||||
pi = gcry_calloc_secure (1, sizeof (*pi) + 100 + 1);
|
||||
if (!pi)
|
||||
{
|
||||
err = gpg_error_from_errno (errno);
|
||||
goto out;
|
||||
}
|
||||
pi->max_length = 100;
|
||||
pi->max_tries = 1;
|
||||
err = agent_askpin (ctrl, description, NULL, pi);
|
||||
if (err)
|
||||
goto out;
|
||||
|
||||
err = ssh_key_to_buffer (key, passphrase, &buffer, &buffer_n);
|
||||
err = ssh_key_to_buffer (key, pi->pin, &buffer, &buffer_n);
|
||||
if (err)
|
||||
goto out;
|
||||
|
||||
/* Store this key to our key storage. */
|
||||
err = agent_write_private_key (key_grip_raw, buffer, buffer_n, 0);
|
||||
if (err)
|
||||
goto out;
|
||||
|
||||
/* Cache this passphrase. */
|
||||
for (i = 0; i < 20; i++)
|
||||
sprintf (key_grip + 2 * i, "%02X", key_grip_raw[i]);
|
||||
|
||||
err = agent_put_cache (key_grip, passphrase, ttl);
|
||||
err = agent_put_cache (key_grip, pi->pin, ttl);
|
||||
if (err)
|
||||
goto out;
|
||||
|
||||
out:
|
||||
/* And add an entry to the sshcontrol file. */
|
||||
err = add_control_entry (ctrl, key_grip, ttl);
|
||||
|
||||
|
||||
out:
|
||||
if (pi && pi->max_length)
|
||||
wipememory (pi->pin, pi->max_length);
|
||||
xfree (pi);
|
||||
xfree (buffer);
|
||||
xfree (comment);
|
||||
free (description);
|
||||
/* FIXME: verify xfree vs free. */
|
||||
free (description); /* (asprintf allocated, thus regular free.) */
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
|
||||
|
||||
static gpg_error_t
|
||||
ssh_identity_drop (gcry_sexp_t key)
|
||||
{
|
||||
|
|
@ -2234,12 +2416,9 @@ ssh_request_process (ctrl_t ctrl, estream_t stream_sock)
|
|||
if (err)
|
||||
goto out;
|
||||
|
||||
if (opt.verbose) /* FIXME: using log_debug is not good with
|
||||
verbose. log_debug should only be used in
|
||||
debugging mode or in sitattions which are
|
||||
unexpected. */
|
||||
log_debug ("received request of length: %u\n",
|
||||
request_data_size);
|
||||
if (opt.verbose > 1)
|
||||
log_info ("received ssh request of length %u\n",
|
||||
(unsigned int)request_data_size);
|
||||
|
||||
request = es_mopen (NULL, 0, 0, 1, realloc_secure, gcry_free, "r+");
|
||||
if (! request)
|
||||
|
|
@ -2277,17 +2456,28 @@ ssh_request_process (ctrl_t ctrl, estream_t stream_sock)
|
|||
break;
|
||||
if (i == DIM (request_specs))
|
||||
{
|
||||
log_debug ("request %u is not supported\n",
|
||||
request_type);
|
||||
log_info ("ssh request %u is not supported\n", request_type);
|
||||
send_err = 1;
|
||||
goto out;
|
||||
}
|
||||
|
||||
if (opt.verbose)
|
||||
log_debug ("executing request handler: %s (%u)\n",
|
||||
log_info ("ssh request handler for %s (%u) started\n",
|
||||
request_specs[i].identifier, request_specs[i].type);
|
||||
|
||||
err = (*request_specs[i].handler) (ctrl, request, response);
|
||||
|
||||
if (opt.verbose)
|
||||
{
|
||||
if (err)
|
||||
log_info ("ssh request handler for %s (%u) failed: %s\n",
|
||||
request_specs[i].identifier, request_specs[i].type,
|
||||
gpg_strerror (err));
|
||||
else
|
||||
log_info ("ssh request handler for %s (%u) ready\n",
|
||||
request_specs[i].identifier, request_specs[i].type);
|
||||
}
|
||||
|
||||
if (err)
|
||||
{
|
||||
send_err = 1;
|
||||
|
|
@ -2295,6 +2485,10 @@ ssh_request_process (ctrl_t ctrl, estream_t stream_sock)
|
|||
}
|
||||
|
||||
response_size = es_ftell (response);
|
||||
if (opt.verbose > 1)
|
||||
log_info ("sending ssh response of length %u\n",
|
||||
(unsigned int)response_size);
|
||||
|
||||
err = es_fseek (response, 0, SEEK_SET);
|
||||
if (err)
|
||||
{
|
||||
|
|
@ -2325,6 +2519,8 @@ ssh_request_process (ctrl_t ctrl, estream_t stream_sock)
|
|||
|
||||
if (send_err)
|
||||
{
|
||||
if (opt.verbose > 1)
|
||||
log_info ("sending ssh error response\n");
|
||||
err = stream_write_uint32 (stream_sock, 1);
|
||||
if (err)
|
||||
goto leave;
|
||||
|
|
@ -2341,7 +2537,7 @@ ssh_request_process (ctrl_t ctrl, estream_t stream_sock)
|
|||
es_fclose (response);
|
||||
xfree (request_data); /* FIXME? */
|
||||
|
||||
return !! err;
|
||||
return !!err;
|
||||
}
|
||||
|
||||
void
|
||||
|
|
@ -2359,6 +2555,21 @@ start_command_handler_ssh (int sock_client)
|
|||
agent_init_default_ctrl (&ctrl);
|
||||
ctrl.connection_fd = sock_client;
|
||||
|
||||
/* Because the ssh protocol does not send us information about the
|
||||
the current TTY setting, we resort here to use those from startup
|
||||
or those explictly set. */
|
||||
if (!ctrl.display && opt.startup_display)
|
||||
ctrl.display = strdup (opt.startup_display);
|
||||
if (!ctrl.ttyname && opt.startup_ttyname)
|
||||
ctrl.ttyname = strdup (opt.startup_ttyname);
|
||||
if (!ctrl.ttytype && opt.startup_ttytype)
|
||||
ctrl.ttytype = strdup (opt.startup_ttytype);
|
||||
if (!ctrl.lc_ctype && opt.startup_lc_ctype)
|
||||
ctrl.lc_ctype = strdup (opt.startup_lc_ctype);
|
||||
if (!ctrl.lc_messages && opt.startup_lc_messages)
|
||||
ctrl.lc_messages = strdup (opt.startup_lc_messages);
|
||||
|
||||
|
||||
/* Create stream from socket. */
|
||||
stream_sock = es_fdopen (sock_client, "r+");
|
||||
if (!stream_sock)
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue