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pam-util: implement our own pam_prompt() replacement, that doesn't log loudly

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pam_prompt() will log very noisely at high error levels if it is called
without a conversation function that works. This is however a frequent
case, given that ssh doesn't provide one. To tone down the misleading
logging a bit, implement our own pam_prompt_graceful() that is just like
pam_prompt(), but reports errors back the caller who then logs (which we
generally do anyway).
This commit is contained in:
Lennart Poettering
2024-01-10 19:06:40 +00:00
committed by Luca Boccassi
parent 54cc0367cb
commit 52e5b950dc
3 changed files with 80 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/home/pam_systemd_home.c
+36 -36
View File
@@ -288,13 +288,13 @@ static int handle_generic_user_record_error(
/* Logs about all errors, except for PAM_CONV_ERR, i.e. when requesting more info failed. */
if (sd_bus_error_has_name(error, BUS_ERROR_HOME_ABSENT)) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL,
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL,
_("Home of user %s is currently absent, please plug in the necessary storage device or backing file system."), user_name);
return pam_syslog_pam_error(handle, LOG_ERR, PAM_PERM_DENIED,
"Failed to acquire home for user %s: %s", user_name, bus_error_message(error, ret));
} else if (sd_bus_error_has_name(error, BUS_ERROR_AUTHENTICATION_LIMIT_HIT)) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Too frequent login attempts for user %s, try again later."), user_name);
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Too frequent login attempts for user %s, try again later."), user_name);
return pam_syslog_pam_error(handle, LOG_ERR, PAM_MAXTRIES,
"Failed to acquire home for user %s: %s", user_name, bus_error_message(error, ret));
@@ -306,10 +306,10 @@ static int handle_generic_user_record_error(
/* This didn't work? Ask for an (additional?) password */
if (strv_isempty(secret->password))
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Password: "));
r = pam_prompt_graceful(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Password: "));
else {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Password incorrect or not sufficient for authentication of user %s."), user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Sorry, try again: "));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Password incorrect or not sufficient for authentication of user %s."), user_name);
r = pam_prompt_graceful(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Sorry, try again: "));
}
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
@@ -331,10 +331,10 @@ static int handle_generic_user_record_error(
/* Hmm, homed asks for recovery key (because no regular password is defined maybe)? Provide it. */
if (strv_isempty(secret->password))
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Recovery key: "));
r = pam_prompt_graceful(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Recovery key: "));
else {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Password/recovery key incorrect or not sufficient for authentication of user %s."), user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Sorry, reenter recovery key: "));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Password/recovery key incorrect or not sufficient for authentication of user %s."), user_name);
r = pam_prompt_graceful(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Sorry, reenter recovery key: "));
}
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
@@ -354,11 +354,11 @@ static int handle_generic_user_record_error(
assert(secret);
if (strv_isempty(secret->password)) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Security token of user %s not inserted."), user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Try again with password: "));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Security token of user %s not inserted."), user_name);
r = pam_prompt_graceful(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Try again with password: "));
} else {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Password incorrect or not sufficient, and configured security token of user %s not inserted."), user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Try again with password: "));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Password incorrect or not sufficient, and configured security token of user %s not inserted."), user_name);
r = pam_prompt_graceful(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Try again with password: "));
}
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
@@ -377,7 +377,7 @@ static int handle_generic_user_record_error(
assert(secret);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Security token PIN: "));
r = pam_prompt_graceful(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Security token PIN: "));
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
@@ -394,7 +394,7 @@ static int handle_generic_user_record_error(
assert(secret);
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Please authenticate physically on security token of user %s."), user_name);
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Please authenticate physically on security token of user %s."), user_name);
r = user_record_set_pkcs11_protected_authentication_path_permitted(secret, true);
if (r < 0)
@@ -405,7 +405,7 @@ static int handle_generic_user_record_error(
assert(secret);
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Please confirm presence on security token of user %s."), user_name);
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Please confirm presence on security token of user %s."), user_name);
r = user_record_set_fido2_user_presence_permitted(secret, true);
if (r < 0)
@@ -416,7 +416,7 @@ static int handle_generic_user_record_error(
assert(secret);
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Please verify user on security token of user %s."), user_name);
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Please verify user on security token of user %s."), user_name);
r = user_record_set_fido2_user_verification_permitted(secret, true);
if (r < 0)
@@ -425,7 +425,7 @@ static int handle_generic_user_record_error(
} else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_PIN_LOCKED)) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Security token PIN is locked, please unlock it first. (Hint: Removal and re-insertion might suffice.)"));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Security token PIN is locked, please unlock it first. (Hint: Removal and re-insertion might suffice.)"));
return PAM_SERVICE_ERR;
} else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_BAD_PIN)) {
@@ -433,8 +433,8 @@ static int handle_generic_user_record_error(
assert(secret);
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Security token PIN incorrect for user %s."), user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Sorry, retry security token PIN: "));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Security token PIN incorrect for user %s."), user_name);
r = pam_prompt_graceful(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Sorry, retry security token PIN: "));
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
@@ -452,8 +452,8 @@ static int handle_generic_user_record_error(
assert(secret);
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Security token PIN of user %s incorrect (only a few tries left!)"), user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Sorry, retry security token PIN: "));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Security token PIN of user %s incorrect (only a few tries left!)"), user_name);
r = pam_prompt_graceful(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Sorry, retry security token PIN: "));
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
@@ -471,8 +471,8 @@ static int handle_generic_user_record_error(
assert(secret);
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Security token PIN of user %s incorrect (only one try left!)"), user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Sorry, retry security token PIN: "));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Security token PIN of user %s incorrect (only one try left!)"), user_name);
r = pam_prompt_graceful(handle, PAM_PROMPT_ECHO_OFF, &newp, _("Sorry, retry security token PIN: "));
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
@@ -616,9 +616,9 @@ static int acquire_home(
* failure. */
if (home_not_active)
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Home of user %s is currently not active, please log in locally first."), ur->user_name);
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Home of user %s is currently not active, please log in locally first."), ur->user_name);
if (home_locked)
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Home of user %s is currently locked, please unlock locally first."), ur->user_name);
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Home of user %s is currently locked, please unlock locally first."), ur->user_name);
if (FLAGS_SET(flags, ACQUIRE_MUST_AUTHENTICATE) || debug)
pam_syslog(handle, FLAGS_SET(flags, ACQUIRE_MUST_AUTHENTICATE) ? LOG_ERR : LOG_DEBUG, "Failed to prompt for password/prompt.");
@@ -643,7 +643,7 @@ static int acquire_home(
}
if (++n_attempts >= 5) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL,
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL,
_("Too many unsuccessful login attempts for user %s, refusing."), ur->user_name);
return pam_syslog_pam_error(handle, LOG_ERR, PAM_MAXTRIES,
"Failed to acquire home for user %s: %s", ur->user_name, bus_error_message(&error, r));
@@ -870,20 +870,20 @@ _public_ PAM_EXTERN int pam_sm_acct_mgmt(
break;
case -ENOLCK:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("User record is blocked, prohibiting access."));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("User record is blocked, prohibiting access."));
return PAM_ACCT_EXPIRED;
case -EL2HLT:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("User record is not valid yet, prohibiting access."));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("User record is not valid yet, prohibiting access."));
return PAM_ACCT_EXPIRED;
case -EL3HLT:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("User record is not valid anymore, prohibiting access."));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("User record is not valid anymore, prohibiting access."));
return PAM_ACCT_EXPIRED;
default:
if (r < 0) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("User record not valid, prohibiting access."));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("User record not valid, prohibiting access."));
return PAM_ACCT_EXPIRED;
}
@@ -895,7 +895,7 @@ _public_ PAM_EXTERN int pam_sm_acct_mgmt(
usec_t n = now(CLOCK_REALTIME);
if (t > n) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Too many logins, try again in %s."),
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Too many logins, try again in %s."),
FORMAT_TIMESPAN(t - n, USEC_PER_SEC));
return PAM_MAXTRIES;
@@ -906,21 +906,21 @@ _public_ PAM_EXTERN int pam_sm_acct_mgmt(
switch (r) {
case -EKEYREVOKED:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Password change required."));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Password change required."));
return PAM_NEW_AUTHTOK_REQD;
case -EOWNERDEAD:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Password expired, change required."));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Password expired, change required."));
return PAM_NEW_AUTHTOK_REQD;
/* Strictly speaking this is only about password expiration, and we might want to allow
* authentication via PKCS#11 or so, but let's ignore this fine distinction for now. */
case -EKEYREJECTED:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Password is expired, but can't change, refusing login."));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Password is expired, but can't change, refusing login."));
return PAM_AUTHTOK_EXPIRED;
case -EKEYEXPIRED:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("Password will expire soon, please change."));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("Password will expire soon, please change."));
break;
case -ESTALE:
@@ -934,7 +934,7 @@ _public_ PAM_EXTERN int pam_sm_acct_mgmt(
default:
if (r < 0) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, _("User record not valid, prohibiting access."));
(void) pam_prompt_graceful(handle, PAM_ERROR_MSG, NULL, _("User record not valid, prohibiting access."));
return PAM_AUTHTOK_EXPIRED;
}
src/shared/pam-util.c
+42
View File
@@ -226,3 +226,45 @@ int pam_get_item_many_internal(pam_handle_t *handle, ...) {
return r;
}
int pam_prompt_graceful(pam_handle_t *handle, int style, char **ret_response, const char *fmt, ...) {
va_list args;
int r;
assert(handle);
assert(fmt);
/* This is just like pam_prompt(), but does not noisily (i.e. beyond LOG_DEBUG) log on its own, but leaves that to the caller */
_cleanup_free_ char *msg = NULL;
va_start(args, fmt);
r = vasprintf(&msg, fmt, args);
va_end(args);
if (r < 0)
return PAM_BUF_ERR;
const struct pam_conv *conv = NULL;
r = pam_get_item(handle, PAM_CONV, (const void**) &conv);
if (!IN_SET(r, PAM_SUCCESS, PAM_BAD_ITEM))
return pam_syslog_pam_error(handle, LOG_DEBUG, r, "Failed to get conversation function structure: @PAMERR@");
if (!conv || !conv->conv) {
pam_syslog(handle, LOG_DEBUG, "No conversation function.");
return PAM_SYSTEM_ERR;
}
struct pam_message message = {
.msg_style = style,
.msg = msg,
};
const struct pam_message *pmessage = &message;
_cleanup_free_ struct pam_response *response = NULL;
r = conv->conv(1, &pmessage, &response, conv->appdata_ptr);
_cleanup_(erase_and_freep) char *rr = response ? response->resp : NULL; /* make sure string is freed + erased */
if (r != PAM_SUCCESS)
return pam_syslog_pam_error(handle, LOG_DEBUG, r, "Conversation function failed: @PAMERR@");
if (ret_response)
*ret_response = TAKE_PTR(rr);
return PAM_SUCCESS;
}
src/shared/pam-util.h
+2
View File
@@ -43,3 +43,5 @@ void pam_cleanup_free(pam_handle_t *handle, void *data, int error_status);
int pam_get_item_many_internal(pam_handle_t *handle, ...);
#define pam_get_item_many(handle, ...) pam_get_item_many_internal(handle, __VA_ARGS__, -1)
int pam_prompt_graceful(pam_handle_t *handle, int style, char **ret_response, const char *fmt, ...) _printf_(4,5);