oysteikt/heimdal
0
0
Fork 0
Code Issues 5 Pull Requests Releases Activity

Use roken_get_*() instead of getpwuuid()

Browse Source 
Using non-reentrant getpwuid() (or getpwnam(), or getspnam())  can be
dangerous.  We had a report of a login application / PAM that calls
those, and Heimdal, by calling them too, clobbered the cached struct
passwd used by the login app / PAM.
This commit is contained in:
Nicolas Williams
2017-10-12 12:24:05 -05:00
committed by Nico Williams
parent 95eb83c424
commit 620862049e
7 changed files with 42 additions and 145 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
lib/krb5/config_file.c
View File

@@ -569,6 +569,7 @@ krb5_config_parse_file_multi (krb5_context context,
if (ISTILDE(fname[0]) && ISPATHSEP(fname[1])) {
#ifndef KRB5_USE_PATH_TOKENS
const char *home = NULL;
char homebuf[MAX_PATH];
if (!_krb5_homedir_access(context)) {
context->config_include_depth--;
@@ -577,12 +578,7 @@ krb5_config_parse_file_multi (krb5_context context,
return EPERM;
}
home = secure_getenv("HOME");
if (home == NULL) {
struct passwd *pw = getpwuid(getuid());
if(pw != NULL)
home = pw->pw_dir;
}
home = roken_get_appdatadir(homebuf, sizeof(homebuf));
if (home) {
int aret;

116
lib/krb5/get_default_principal.c
View File

@@ -37,113 +37,37 @@
* Try to find out what's a reasonable default principal.
*/
static const char*
get_env_user(void)
{
const char *user = getenv("USER");
if(user == NULL)
user = getenv("LOGNAME");
if(user == NULL)
user = getenv("USERNAME");
return user;
}
#ifndef _WIN32
/*
* Will only use operating-system dependant operation to get the
* default principal, for use of functions that in ccache layer to
* avoid recursive calls.
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
_krb5_get_default_principal_local (krb5_context context,
krb5_principal *princ)
{
krb5_error_code ret;
const char *user;
uid_t uid;
const char *second_component = NULL;
char userbuf[128];
*princ = NULL;
uid = getuid();
if(uid == 0) {
user = getlogin();
if(user == NULL)
user = get_env_user();
if(user != NULL && strcmp(user, "root") != 0)
ret = krb5_make_principal(context, princ, NULL, user, "root", NULL);
else
ret = krb5_make_principal(context, princ, NULL, "root", NULL);
} else {
struct passwd *pw = getpwuid(uid);
if(pw != NULL)
user = pw->pw_name;
else {
user = get_env_user();
if(user == NULL)
user = getlogin();
}
if(user == NULL) {
krb5_set_error_message(context, ENOTTY,
N_("unable to figure out current "
"principal", ""));
return ENOTTY; /* XXX */
}
ret = krb5_make_principal(context, princ, NULL, user, NULL);
/*
* NOTE: We depend on roken_get_username() preferentially using
* getlogin_r() first when !issuid() && getuid() == 0, otherwise we
* won't figure out to output <username>/root@DEFAULT_REALM.
*/
user = roken_get_username(userbuf, sizeof(userbuf));
if (user == NULL) {
krb5_set_error_message(context, ENOTTY,
N_("unable to figure out current principal",
""));
return ENOTTY; /* XXX */
}
return ret;
#ifndef WIN32
if (!issuid() && getuid() == 0 && strcmp(user, "root") != 0)
second_component = "root"; /* We'll use <user>/root */
#endif;
return krb5_make_principal(context, princ, NULL, user,
second_component, NULL);
}
#else /* _WIN32 */
#define SECURITY_WIN32
#include <security.h>
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
_krb5_get_default_principal_local(krb5_context context,
krb5_principal *princ)
{
/* See if we can get the principal first. We only expect this to
work if logged into a domain. */
{
char username[1024];
ULONG sz = sizeof(username);
if (GetUserNameEx(NameUserPrincipal, username, &sz)) {
return krb5_parse_name_flags(context, username,
KRB5_PRINCIPAL_PARSE_ENTERPRISE,
princ);
}
}
/* Just get the Windows username. This should pretty much always
work. */
{
char username[1024];
DWORD dsz = sizeof(username);
if (GetUserName(username, &dsz)) {
return krb5_make_principal(context, princ, NULL, username, NULL);
}
}
/* Failing that, we look at the environment */
{
const char * username = get_env_user();
if (username == NULL) {
krb5_set_error_string(context,
"unable to figure out current principal");
return ENOTTY; /* Really? */
}
return krb5_make_principal(context, princ, NULL, username, NULL);
}
}
#endif
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_get_default_principal (krb5_context context,
krb5_principal *princ)