From cbb0e3ea444ff761b58c8f9355af1dfc631bc64b Mon Sep 17 00:00:00 2001 From: Anders Kaseorg Date: Thu, 14 Oct 2010 02:59:49 -0400 Subject: [PATCH] Move the repetitive NSS walking logic into an include file Signed-off-by: Anders Kaseorg --- nonlocal-group.c | 289 ++++++++++++---------------------------------- nonlocal-passwd.c | 253 ++++++++++++---------------------------- nonlocal-shadow.c | 113 +++++++----------- nonlocal.h | 11 ++ walk_nss.h | 87 ++++++++++++++ 5 files changed, 289 insertions(+), 464 deletions(-) create mode 100644 walk_nss.h diff --git a/nonlocal-group.c b/nonlocal-group.c index c75ecf7..fa7fbaf 100644 --- a/nonlocal-group.c +++ b/nonlocal-group.c @@ -51,75 +51,49 @@ _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, char *buffer, size_t buflen, int *errnop); -static service_user * -nss_group_nonlocal_database(void) +static service_user *__nss_group_nonlocal_database; + +static int +internal_function +__nss_group_nonlocal_lookup(service_user **ni, const char *fct_name, + void **fctp) { - static service_user *nip = NULL; - if (nip == NULL) - __nss_database_lookup("group_nonlocal", NULL, "", &nip); + if (__nss_group_nonlocal_database == NULL + && __nss_database_lookup("group_nonlocal", NULL, NULL, + &__nss_group_nonlocal_database) < 0) + return -1; + + *ni = __nss_group_nonlocal_database; - return nip; + *fctp = __nss_lookup_function(*ni, fct_name); + return 0; } enum nss_status check_nonlocal_gid(const char *user, gid_t gid, int *errnop) { - static const char *fct_name = "getgrgid_r"; - static service_user *startp = NULL; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(gid_t gid, struct group *grp, - char *buffer, size_t buflen, int *errnop); - void *ptr; - } fct; struct group gbuf; - int old_errno = errno; - + char *buf; size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX); - char *buf = malloc(buflen); - errno = old_errno; - if (buf == NULL) { - *errnop = ENOMEM; - return NSS_STATUS_TRYAGAIN; - } - - if (fct_start == NULL && - __nss_group_lookup(&startp, fct_name, &fct_start) != 0) { - free(buf); - return NSS_STATUS_UNAVAIL; - } - nip = startp; - fct.ptr = fct_start; - do { - morebuf: - if (fct.l == _nss_nonlocal_getgrgid_r) - status = NSS_STATUS_NOTFOUND; - else - status = DL_CALL_FCT(fct.l, (gid, &gbuf, buf, buflen, errnop)); - if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) { - free(buf); - buflen *= 2; - buf = malloc(buflen); - errno = old_errno; - if (buf == NULL) { - *errnop = ENOMEM; - return NSS_STATUS_TRYAGAIN; - } - goto morebuf; - } - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); + const struct walk_nss w = { + .lookup = &__nss_group_lookup, .fct_name = "getgrgid_r", + .status = &status, .errnop = errnop, .buf = &buf, .buflen = &buflen + }; + const __typeof__(&_nss_nonlocal_getgrgid_r) self = &_nss_nonlocal_getgrgid_r; +#define args (gid, &gbuf, buf, buflen, errnop) +#include "walk_nss.h" +#undef args if (status == NSS_STATUS_SUCCESS) { syslog(LOG_DEBUG, "nss_nonlocal: removing local group %u (%s) from non-local user %s\n", gbuf.gr_gid, gbuf.gr_name, user); + free(buf); status = NSS_STATUS_NOTFOUND; } else if (status != NSS_STATUS_TRYAGAIN) { status = NSS_STATUS_SUCCESS; } - free(buf); return status; } @@ -147,63 +121,20 @@ check_nonlocal_group(const char *user, struct group *grp, int *errnop) enum nss_status get_local_group(const char *name, struct group *grp, char **buffer, int *errnop) { - static const char *fct_name = "getgrnam_r"; - static service_user *startp = NULL; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(const char *name, struct group *grp, - char *buffer, size_t buflen, int *errnop); - void *ptr; - } fct; - size_t buflen; - int old_errno = errno; - - buflen = sysconf(_SC_GETGR_R_SIZE_MAX); - *buffer = malloc(buflen); - errno = old_errno; - if (*buffer == NULL) { - *errnop = ENOMEM; - return NSS_STATUS_TRYAGAIN; - } - - if (fct_start == NULL && - __nss_group_lookup(&startp, fct_name, &fct_start) != 0) { - free(*buffer); - *buffer = NULL; - return NSS_STATUS_UNAVAIL; - } - nip = startp; - fct.ptr = fct_start; - do { - morebuf: - if (fct.l == _nss_nonlocal_getgrnam_r) - status = NSS_STATUS_NOTFOUND; - else - status = DL_CALL_FCT(fct.l, (name, grp, *buffer, buflen, errnop)); - if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) { - free(*buffer); - buflen *= 2; - *buffer = malloc(buflen); - errno = old_errno; - if (*buffer == NULL) { - *errnop = ENOMEM; - return NSS_STATUS_TRYAGAIN; - } - goto morebuf; - } - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); - - if (status != NSS_STATUS_SUCCESS) { - free(*buffer); - *buffer = NULL; - } - + size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX); + const struct walk_nss w = { + .lookup = &__nss_group_lookup, .fct_name = "getgrnam_r", + .status = &status, .errnop = errnop, .buf = buffer, .buflen = &buflen + }; + const __typeof__(&_nss_nonlocal_getgrnam_r) self = &_nss_nonlocal_getgrnam_r; +#define args (name, grp, *buffer, buflen, errnop) +#include "walk_nss.h" +#undef args return status; } -static service_user *grent_nip = NULL; +static service_user *grent_startp, *grent_nip; static void *grent_fct_start; static union { enum nss_status (*l)(struct group *grp, char *buffer, size_t buflen, @@ -215,33 +146,22 @@ static const char *grent_fct_name = "getgrent_r"; enum nss_status _nss_nonlocal_setgrent(int stayopen) { - static const char *fct_name = "setgrent"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(int stayopen); - void *ptr; - } fct; - - nip = nss_group_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, (stayopen)); - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); + const struct walk_nss w = { + .lookup = &__nss_group_nonlocal_lookup, .fct_name = "setgrent", + .status = &status + }; + const __typeof__(&_nss_nonlocal_setgrent) self = NULL; +#define args (stayopen) +#include "walk_nss.h" +#undef args if (status != NSS_STATUS_SUCCESS) return status; - grent_nip = nip; if (grent_fct_start == NULL) - grent_fct_start = __nss_lookup_function(nip, grent_fct_name); + __nss_group_nonlocal_lookup(&grent_startp, grent_fct_name, + &grent_fct_start); + grent_nip = grent_startp; grent_fct.ptr = grent_fct_start; return NSS_STATUS_SUCCESS; } @@ -249,29 +169,18 @@ _nss_nonlocal_setgrent(int stayopen) enum nss_status _nss_nonlocal_endgrent(void) { - static const char *fct_name = "endgrent"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(void); - void *ptr; - } fct; + const struct walk_nss w = { + .lookup = &__nss_group_nonlocal_lookup, .fct_name = "endgrent", + .status = &status + }; + const __typeof__(&_nss_nonlocal_endgrent) self = NULL; grent_nip = NULL; - nip = nss_group_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, ()); - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); +#define args () +#include "walk_nss.h" +#undef args return status; } @@ -316,34 +225,20 @@ enum nss_status _nss_nonlocal_getgrnam_r(const char *name, struct group *grp, char *buffer, size_t buflen, int *errnop) { - static const char *fct_name = "getgrnam_r"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(const char *name, struct group *grp, - char *buffer, size_t buflen, int *errnop); - void *ptr; - } fct; + const struct walk_nss w = { + .lookup = &__nss_group_nonlocal_lookup, .fct_name = "getgrnam_r", + .status = &status, .errnop = errnop + }; + const __typeof__(&_nss_nonlocal_getgrnam_r) self = NULL; char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') return NSS_STATUS_UNAVAIL; - nip = nss_group_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, (name, grp, buffer, buflen, errnop)); - if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) - break; - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); +#define args (name, grp, buffer, buflen, errnop) +#include "walk_nss.h" +#undef args if (status != NSS_STATUS_SUCCESS) return status; @@ -359,34 +254,20 @@ enum nss_status _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, char *buffer, size_t buflen, int *errnop) { - static const char *fct_name = "getgrgid_r"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(gid_t gid, struct group *grp, - char *buffer, size_t buflen, int *errnop); - void *ptr; - } fct; + const struct walk_nss w = { + .lookup = &__nss_group_nonlocal_lookup, .fct_name = "getgrgid_r", + .status = &status, .errnop = errnop + }; + const __typeof__(&_nss_nonlocal_getgrgid_r) self = NULL; char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') return NSS_STATUS_UNAVAIL; - nip = nss_group_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, (gid, grp, buffer, buflen, errnop)); - if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) - break; - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); +#define args (gid, grp, buffer, buflen, errnop) +#include "walk_nss.h" +#undef args if (status != NSS_STATUS_SUCCESS) return status; @@ -403,16 +284,12 @@ _nss_nonlocal_initgroups_dyn(const char *user, gid_t group, long int *start, long int *size, gid_t **groupsp, long int limit, int *errnop) { - static const char *fct_name = "initgroups_dyn"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(const char *user, gid_t group, long int *start, - long int *size, gid_t **groupsp, long int limit, - int *errnop); - void *ptr; - } fct; + const struct walk_nss w = { + .lookup = &__nss_group_nonlocal_lookup, .fct_name = "initgroups_dyn", + .status = &status, .errnop = errnop + }; + const __typeof__(&_nss_nonlocal_initgroups_dyn) self = NULL; struct group local_users_group, nonlocal_users_group; gid_t local_users_gid, gid; @@ -493,21 +370,9 @@ _nss_nonlocal_initgroups_dyn(const char *user, gid_t group, long int *start, in = out = *start; - nip = nss_group_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, (user, group, start, size, groupsp, limit, errnop)); - if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) - break; - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); +#define args (user, group, start, size, groupsp, limit, errnop) +#include "walk_nss.h" +#undef args if (status != NSS_STATUS_SUCCESS) return status; diff --git a/nonlocal-passwd.c b/nonlocal-passwd.c index bd9d9ad..052af95 100644 --- a/nonlocal-passwd.c +++ b/nonlocal-passwd.c @@ -49,75 +49,49 @@ _nss_nonlocal_getpwnam_r(const char *name, struct passwd *pwd, char *buffer, size_t buflen, int *errnop); -static service_user * -nss_passwd_nonlocal_database(void) +static service_user *__nss_passwd_nonlocal_database; + +static int +internal_function +__nss_passwd_nonlocal_lookup(service_user **ni, const char *fct_name, + void **fctp) { - static service_user *nip = NULL; - if (nip == NULL) - __nss_database_lookup("passwd_nonlocal", NULL, "", &nip); + if (__nss_passwd_nonlocal_database == NULL + && __nss_database_lookup("passwd_nonlocal", NULL, NULL, + &__nss_passwd_nonlocal_database) < 0) + return -1; + + *ni = __nss_passwd_nonlocal_database; - return nip; + *fctp = __nss_lookup_function(*ni, fct_name); + return 0; } enum nss_status check_nonlocal_uid(const char *user, uid_t uid, int *errnop) { - static const char *fct_name = "getpwuid_r"; - static service_user *startp = NULL; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(uid_t uid, struct passwd *pwd, - char *buffer, size_t buflen, int *errnop); - void *ptr; - } fct; struct passwd pwbuf; - int old_errno = errno; - + char *buf; size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX); - char *buf = malloc(buflen); - errno = old_errno; - if (buf == NULL) { - *errnop = ENOMEM; - return NSS_STATUS_TRYAGAIN; - } - - if (fct_start == NULL && - __nss_passwd_lookup(&startp, fct_name, &fct_start) != 0) { - free(buf); - return NSS_STATUS_UNAVAIL; - } - nip = startp; - fct.ptr = fct_start; - do { - morebuf: - if (fct.l == _nss_nonlocal_getpwuid_r) - status = NSS_STATUS_NOTFOUND; - else - status = DL_CALL_FCT(fct.l, (uid, &pwbuf, buf, buflen, errnop)); - if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) { - free(buf); - buflen *= 2; - buf = malloc(buflen); - errno = old_errno; - if (buf == NULL) { - *errnop = ENOMEM; - return NSS_STATUS_TRYAGAIN; - } - goto morebuf; - } - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); + const struct walk_nss w = { + .lookup = &__nss_passwd_lookup, .fct_name = "getpwuid_r", + .status = &status, .errnop = errnop, .buf = &buf, .buflen = &buflen + }; + const __typeof__(&_nss_nonlocal_getpwuid_r) self = &_nss_nonlocal_getpwuid_r; +#define args (uid, &pwbuf, buf, buflen, errnop) +#include "walk_nss.h" +#undef args if (status == NSS_STATUS_SUCCESS) { syslog(LOG_ERR, "nss_nonlocal: possible spoofing attack: non-local user %s has same UID as local user %s!\n", user, pwbuf.pw_name); + free(buf); status = NSS_STATUS_NOTFOUND; } else if (status != NSS_STATUS_TRYAGAIN) { status = NSS_STATUS_SUCCESS; } - free(buf); return status; } @@ -146,64 +120,31 @@ check_nonlocal_passwd(const char *user, struct passwd *pwd, int *errnop) enum nss_status check_nonlocal_user(const char *user, int *errnop) { - static const char *fct_name = "getpwnam_r"; - static service_user *startp = NULL; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(const char *name, struct passwd *pwd, - char *buffer, size_t buflen, int *errnop); - void *ptr; - } fct; struct passwd pwbuf; - int old_errno = errno; - + char *buf; size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX); - char *buf = malloc(buflen); - errno = old_errno; - if (buf == NULL) { - *errnop = ENOMEM; - return NSS_STATUS_TRYAGAIN; - } + const struct walk_nss w = { + .lookup = __nss_passwd_lookup, .fct_name = "getpwnam_r", + .status = &status, .errnop = errnop, .buf = &buf, .buflen = &buflen + }; + const __typeof__(&_nss_nonlocal_getpwnam_r) self = &_nss_nonlocal_getpwnam_r; +#define args (user, &pwbuf, buf, buflen, errnop) +#include "walk_nss.h" +#undef args - if (fct_start == NULL && - __nss_passwd_lookup(&startp, fct_name, &fct_start) != 0) { + if (status == NSS_STATUS_SUCCESS) { free(buf); - return NSS_STATUS_UNAVAIL; - } - nip = startp; - fct.ptr = fct_start; - do { - morebuf: - if (fct.l == _nss_nonlocal_getpwnam_r) - status = NSS_STATUS_NOTFOUND; - else - status = DL_CALL_FCT(fct.l, (user, &pwbuf, buf, buflen, errnop)); - if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) { - free(buf); - buflen *= 2; - buf = malloc(buflen); - errno = old_errno; - if (buf == NULL) { - *errnop = ENOMEM; - return NSS_STATUS_TRYAGAIN; - } - goto morebuf; - } - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); - - if (status == NSS_STATUS_SUCCESS) status = NSS_STATUS_NOTFOUND; - else if (status != NSS_STATUS_TRYAGAIN) + } else if (status != NSS_STATUS_TRYAGAIN) { status = NSS_STATUS_SUCCESS; + } - free(buf); return status; } -static service_user *pwent_nip = NULL; +static service_user *pwent_startp, *pwent_nip; static void *pwent_fct_start; static union { enum nss_status (*l)(struct passwd *pwd, char *buffer, size_t buflen, @@ -215,33 +156,22 @@ static const char *pwent_fct_name = "getpwent_r"; enum nss_status _nss_nonlocal_setpwent(int stayopen) { - static const char *fct_name = "setpwent"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(int stayopen); - void *ptr; - } fct; - - nip = nss_passwd_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, (stayopen)); - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); + const struct walk_nss w = { + .lookup = &__nss_passwd_nonlocal_lookup, .fct_name = "setpwent", + .status = &status + }; + const __typeof__(&_nss_nonlocal_setpwent) self = NULL; +#define args (stayopen) +#include "walk_nss.h" +#undef args if (status != NSS_STATUS_SUCCESS) return status; - pwent_nip = nip; if (pwent_fct_start == NULL) - pwent_fct_start = __nss_lookup_function(nip, pwent_fct_name); + __nss_passwd_nonlocal_lookup(&pwent_startp, pwent_fct_name, + &pwent_fct_start); + pwent_nip = pwent_startp; pwent_fct.ptr = pwent_fct_start; return NSS_STATUS_SUCCESS; } @@ -249,29 +179,18 @@ _nss_nonlocal_setpwent(int stayopen) enum nss_status _nss_nonlocal_endpwent(void) { - static const char *fct_name = "endpwent"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(void); - void *ptr; - } fct; + const struct walk_nss w = { + .lookup = &__nss_passwd_nonlocal_lookup, .fct_name = "endpwent", + .status = &status + }; + const __typeof__(&_nss_nonlocal_endpwent) self = NULL; pwent_nip = NULL; - nip = nss_passwd_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, ()); - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); +#define args () +#include "walk_nss.h" +#undef args return status; } @@ -316,35 +235,21 @@ enum nss_status _nss_nonlocal_getpwnam_r(const char *name, struct passwd *pwd, char *buffer, size_t buflen, int *errnop) { - static const char *fct_name = "getpwnam_r"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(const char *name, struct passwd *pwd, - char *buffer, size_t buflen, int *errnop); - void *ptr; - } fct; int group_errno; + const struct walk_nss w = { + .lookup = __nss_passwd_nonlocal_lookup, .fct_name = "getpwnam_r", + .status = &status, .errnop = errnop + }; + const __typeof__(&_nss_nonlocal_getpwnam_r) self = NULL; char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') return NSS_STATUS_UNAVAIL; - nip = nss_passwd_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, (name, pwd, buffer, buflen, errnop)); - if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) - break; - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); +#define args (name, pwd, buffer, buflen, errnop) +#include "walk_nss.h" +#undef args if (status != NSS_STATUS_SUCCESS) return status; @@ -367,35 +272,21 @@ enum nss_status _nss_nonlocal_getpwuid_r(uid_t uid, struct passwd *pwd, char *buffer, size_t buflen, int *errnop) { - static const char *fct_name = "getpwuid_r"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(uid_t uid, struct passwd *pwd, - char *buffer, size_t buflen, int *errnop); - void *ptr; - } fct; int group_errno; + const struct walk_nss w = { + .lookup = &__nss_passwd_nonlocal_lookup, .fct_name = "getpwuid_r", + .status = &status, .errnop = errnop + }; + const __typeof__(&_nss_nonlocal_getpwuid_r) self = NULL; char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') return NSS_STATUS_UNAVAIL; - nip = nss_passwd_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, (uid, pwd, buffer, buflen, errnop)); - if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) - break; - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); +#define args (uid, pwd, buffer, buflen, errnop) +#include "walk_nss.h" +#undef args if (status != NSS_STATUS_SUCCESS) return status; diff --git a/nonlocal-shadow.c b/nonlocal-shadow.c index b4b6b1f..ab8f442 100644 --- a/nonlocal-shadow.c +++ b/nonlocal-shadow.c @@ -39,18 +39,26 @@ #include "nonlocal.h" -static service_user * -nss_shadow_nonlocal_database(void) +static service_user *__nss_shadow_nonlocal_database; + +static int +internal_function +__nss_shadow_nonlocal_lookup(service_user **ni, const char *fct_name, + void **fctp) { - static service_user *nip = NULL; - if (nip == NULL) - __nss_database_lookup("shadow_nonlocal", NULL, "", &nip); + if (__nss_shadow_nonlocal_database == NULL + && __nss_database_lookup("shadow_nonlocal", NULL, NULL, + &__nss_shadow_nonlocal_database) < 0) + return -1; + + *ni = __nss_shadow_nonlocal_database; - return nip; + *fctp = __nss_lookup_function(*ni, fct_name); + return 0; } -static service_user *spent_nip = NULL; +static service_user *spent_startp, *spent_nip; static void *spent_fct_start; static union { enum nss_status (*l)(struct spwd *pwd, char *buffer, size_t buflen, @@ -62,33 +70,22 @@ static const char *spent_fct_name = "getspent_r"; enum nss_status _nss_nonlocal_setspent(int stayopen) { - static const char *fct_name = "setspent"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(int stayopen); - void *ptr; - } fct; - - nip = nss_shadow_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, (stayopen)); - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); + const struct walk_nss w = { + .lookup = &__nss_shadow_nonlocal_lookup, .fct_name = "setspent", + .status = &status + }; + const __typeof__(&_nss_nonlocal_setspent) self = NULL; +#define args (stayopen) +#include "walk_nss.h" +#undef args if (status != NSS_STATUS_SUCCESS) return status; - spent_nip = nip; if (spent_fct_start == NULL) - spent_fct_start = __nss_lookup_function(nip, spent_fct_name); + __nss_shadow_nonlocal_lookup(&spent_startp, spent_fct_name, + &spent_fct_start); + spent_nip = spent_startp; spent_fct.ptr = spent_fct_start; return NSS_STATUS_SUCCESS; } @@ -96,29 +93,18 @@ _nss_nonlocal_setspent(int stayopen) enum nss_status _nss_nonlocal_endspent(void) { - static const char *fct_name = "endspent"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(void); - void *ptr; - } fct; + const struct walk_nss w = { + .lookup = &__nss_shadow_nonlocal_lookup, .fct_name = "endspent", + .status = &status + }; + const __typeof__(&_nss_nonlocal_endspent) self = NULL; spent_nip = NULL; - nip = nss_shadow_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, ()); - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); +#define args () +#include "walk_nss.h" +#undef args return status; } @@ -153,30 +139,15 @@ enum nss_status _nss_nonlocal_getspnam_r(const char *name, struct spwd *pwd, char *buffer, size_t buflen, int *errnop) { - static const char *fct_name = "getspnam_r"; - static void *fct_start = NULL; enum nss_status status; - service_user *nip; - union { - enum nss_status (*l)(const char *name, struct spwd *pwd, - char *buffer, size_t buflen, int *errnop); - void *ptr; - } fct; - - nip = nss_shadow_nonlocal_database(); - if (nip == NULL) - return NSS_STATUS_UNAVAIL; - if (fct_start == NULL) - fct_start = __nss_lookup_function(nip, fct_name); - fct.ptr = fct_start; - do { - if (fct.ptr == NULL) - status = NSS_STATUS_UNAVAIL; - else - status = DL_CALL_FCT(fct.l, (name, pwd, buffer, buflen, errnop)); - if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) - break; - } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); + const struct walk_nss w = { + .lookup = __nss_shadow_nonlocal_lookup, .fct_name = "getspnam_r", + .status = &status, .errnop = errnop + }; + const __typeof__(&_nss_nonlocal_getspnam_r) self = NULL; +#define args (name, pwd, buffer, buflen, errnop) +#include "walk_nss.h" +#undef args if (status != NSS_STATUS_SUCCESS) return status; diff --git a/nonlocal.h b/nonlocal.h index 7d644ae..a0746d4 100644 --- a/nonlocal.h +++ b/nonlocal.h @@ -27,6 +27,17 @@ #define NONLOCAL_H #include "config.h" +#include "nsswitch-internal.h" + +struct walk_nss { + enum nss_status *status; + int (*lookup)(service_user **ni, const char *fct_name, + void **fctp) internal_function; + const char *fct_name; + int *errnop; + char **buf; + size_t *buflen; +}; enum nss_status check_nonlocal_uid(const char *user, uid_t uid, int *errnop); enum nss_status check_nonlocal_gid(const char *user, gid_t gid, int *errnop); diff --git a/walk_nss.h b/walk_nss.h new file mode 100644 index 0000000..93af177 --- /dev/null +++ b/walk_nss.h @@ -0,0 +1,87 @@ +/* + * walk_nss.h + * NSS walking template for nss_nonlocal proxy + * + * Copyright © 2011 Anders Kaseorg and Tim Abbott + * + * + * This file is part of nss_nonlocal. + * + * nss_nonlocal is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public License + * as published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * nss_nonlocal is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with nss_nonlocal; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301 USA + */ + +{ + static service_user *startp = NULL; + static void *fct_start = NULL; + + service_user *nip; + union { + __typeof__(self) l; + void *ptr; + } fct; + int old_errno = errno; + + if (fct_start == NULL && + w.lookup(&startp, w.fct_name, &fct_start) != 0) { + *w.status = NSS_STATUS_UNAVAIL; + goto walk_nss_out; + } + + nip = startp; + fct.ptr = fct_start; + + if (w.buf != NULL) { + *w.buf = malloc(*w.buflen); + errno = old_errno; + if (*w.buf == NULL) { + *w.status = NSS_STATUS_TRYAGAIN; + *w.errnop = ENOMEM; + goto walk_nss_out; + } + } + + do { + walk_nss_morebuf: + if (fct.ptr == NULL) + *w.status = NSS_STATUS_UNAVAIL; + else if (self != NULL && fct.l == self) + *w.status = NSS_STATUS_NOTFOUND; + else + *w.status = DL_CALL_FCT(fct.l, args); + if (*w.status == NSS_STATUS_TRYAGAIN && + w.errnop != NULL && *w.errnop == ERANGE) { + if (w.buf == NULL) + break; + free(*w.buf); + *w.buflen *= 2; + *w.buf = malloc(*w.buflen); + errno = old_errno; + if (*w.buf == NULL) { + *w.errnop = ENOMEM; + goto walk_nss_out; + } + goto walk_nss_morebuf; + } + } while (__nss_next(&nip, w.fct_name, &fct.ptr, *w.status, 0) == 0); + + if (w.buf != NULL && *w.status != NSS_STATUS_SUCCESS) { + free(*w.buf); + *w.buf = NULL; + } + + walk_nss_out: + ; +} -- 2.44.0