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MAX_PASSLEN based authentication

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This commit is contained in:
Vladimir 'phcoder' Serbinenko 2009-11-15 23:36:42 +01:00
parent 10e53efaee
commit 228734ab02
3 changed files with 13 additions and 63 deletions
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13
commands/password.c
View file

@ -26,18 +26,20 @@
static grub_dl_t my_mod;
#define MAX_PASSLEN 1024
static grub_err_t
check_password (const char *user,
void *password)
{
char entered[1024];
char entered[MAX_PASSLEN];
grub_memset (entered, 0, sizeof (entered));
if (!GRUB_GET_PASSWORD (entered, sizeof (entered) - 1))
return GRUB_ACCESS_DENIED;
if (grub_auth_strcmp (entered, password) != 0)
if (grub_crypto_memcmp (entered, password, MAX_PASSLEN) != 0)
return GRUB_ACCESS_DENIED;
grub_auth_authenticate (user);
@ -51,13 +53,18 @@ grub_cmd_password (grub_command_t cmd __attribute__ ((unused)),
{
grub_err_t err;
char *pass;
int copylen;
if (argc != 2)
return grub_error (GRUB_ERR_BAD_ARGUMENT, "Two arguments expected.");
pass = grub_strdup (args[1]);
pass = grub_zalloc (MAX_PASSLEN);
if (!pass)
return grub_errno;
copylen = grub_strlen (argv[1]);
if (copylen >= MAX_PASSLEN)
copylen = MAX_PASSLEN - 1;
grub_memcpy (pass, argv[1], copylen);
err = grub_auth_register_authentication (args[0], check_password, pass);
if (err)

7
include/grub/auth.h
View file

@ -15,7 +15,7 @@
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef GRUB_AURH_HEADER
#ifndef GRUB_AUTH_HEADER
#define GRUB_AUTH_HEADER 1
#include <grub/err.h>
@ -26,11 +26,6 @@
string, len, \
'*', 0, 0)
/* Like strcmp but untimeable. Accepts NULL as second argument. */
int grub_auth_strcmp (const char *user_input, const char *template);
/* Like strcmp but untimeable and ignores commas in needle. */
int grub_auth_strword (const char *haystack, const char *needle);
typedef grub_err_t (*grub_auth_callback_t) (const char*, void *);
grub_err_t grub_auth_register_authentication (const char *user,

56
normal/auth.c
View file

@ -35,58 +35,6 @@ struct grub_auth_user
struct grub_auth_user *users = NULL;
int
grub_auth_strcmp (const char *s1, const char *s2)
{
int ret;
grub_uint64_t end;
end = grub_get_time_ms () + 100;
ret = grub_strcmp (s1, s2);
/* This prevents an attacker from deriving information about the
password from the time it took to execute this function. */
while (grub_get_time_ms () < end);
return ret;
}
static int
grub_iswordseparator (int c)
{
return (grub_isspace (c) || c == ',' || c == ';' || c == '|' || c == '&');
}
int
grub_auth_strword (const char *haystack, const char *needle)
{
const char *n_pos = needle;
int found = 0;
while (grub_iswordseparator (*haystack))
haystack++;
while (*haystack)
{
int ok = 1;
/* Crawl both the needle and the haystack word we're on. */
while(*haystack && !grub_iswordseparator (*haystack))
{
if (*haystack == *n_pos && ok)
n_pos++;
else
ok = 0;
haystack++;
}
if (ok)
found = 1;
}
return found;
}
grub_err_t
grub_auth_register_authentication (const char *user,
grub_auth_callback_t callback,
@ -193,8 +141,8 @@ is_authenticated (const char *userlist)
return 0;
name = ((struct grub_auth_user *) item)->name;
return (userlist && grub_auth_strword (userlist, name))
|| grub_auth_strword (superusers, name);
return (userlist && grub_strword (userlist, name))
|| grub_strword (superusers, name);
}
superusers = grub_env_get ("superusers");