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Added support for multiple homes in pam_zfs_key module #18084

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Merged
tonyhutter merged 1 commit into from
Feb 4, 2026
Merged

Added support for multiple homes in pam_zfs_key module #18084

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1 change: 1 addition & 0 deletions contrib/debian/openzfs-libpam-zfs.install
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Original file line number Diff line number Diff line change
@@ -1,2 +1,3 @@
usr/lib/*/security/pam_zfs_key.so
usr/share/man/man8/pam_zfs_key.8
usr/share/pam-configs/zfs_key
278 changes: 190 additions & 88 deletions contrib/pam_zfs_key/pam_zfs_key.c
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Original file line number Diff line number Diff line change
Expand Up @@ -754,6 +754,82 @@ zfs_key_config_get_dataset(pam_handle_t *pamh, zfs_key_config_t *config)
return (ret);
}

/*
* Callback type for foreach_dataset.
* Returns 0 on success, -1 on failure.
*/
typedef int (*dataset_callback_t)(pam_handle_t *, zfs_key_config_t *,
const char *, void *);

/*
* Iterate over comma-separated homes prefixes and call callback for each
* existing dataset. Returns number of successful callbacks, or -1 if none
* succeeded.
*/
static int
foreach_dataset(pam_handle_t *pamh, zfs_key_config_t *config,
dataset_callback_t callback, void *data)
{
if (config->homes_prefix == NULL)
return (-1);

/* Check if this is a comma-separated list */
if (strchr(config->homes_prefix, ',') == NULL) {
/* Single home - use existing logic */
char *dataset = zfs_key_config_get_dataset(pamh, config);
if (dataset == NULL)
return (-1);
int ret = callback(pamh, config, dataset, data);
free(dataset);
return (ret == 0 ? 1 : -1);
}

/* Multiple homes - parse and iterate */
pam_syslog(pamh, LOG_DEBUG,
"processing multiple home prefixes: %s", config->homes_prefix);

char *homes_copy = strdup(config->homes_prefix);
if (homes_copy == NULL)
return (-1);

char *saved_prefix = config->homes_prefix;
char *saveptr;
char *token = strtok_r(homes_copy, ",", &saveptr);
int success_count = 0;
boolean_t failed = B_FALSE;

while (token != NULL) {
/* Temporarily set homes_prefix to this single prefix */
config->homes_prefix = token;
char *dataset = zfs_key_config_get_dataset(pamh, config);
if (dataset != NULL) {
pam_syslog(pamh, LOG_DEBUG,
"processing dataset '%s' for prefix '%s'",
dataset, token);
if (callback(pamh, config, dataset, data) == 0) {
success_count++;
} else {
failed = B_TRUE;
pam_syslog(pamh, LOG_WARNING,
"operation failed for dataset '%s'",
dataset);
}
free(dataset);
} else {
pam_syslog(pamh, LOG_DEBUG,
"no dataset found for prefix '%s', skip", token);
}
token = strtok_r(NULL, ",", &saveptr);
}

config->homes_prefix = saved_prefix;
free(homes_copy);
pam_syslog(pamh, LOG_DEBUG,
"processed %d datasets, %s",
success_count, failed ? "with failures" : "all successful");
return (!failed && success_count > 0 ? success_count : -1);
}

static int
zfs_key_config_modify_session_counter(pam_handle_t *pamh,
zfs_key_config_t *config, int delta)
Expand Down Expand Up @@ -825,6 +901,15 @@ zfs_key_config_modify_session_counter(pam_handle_t *pamh,
return (counter_value);
}

/* Callback for authentication - verify password works (noop mode) */
static int
auth_callback(pam_handle_t *pamh, zfs_key_config_t *config,
const char *dataset, void *data)
{
const char *passphrase = data;
return (decrypt_mount(pamh, config, dataset, passphrase, B_TRUE));
}

__attribute__((visibility("default")))
PAM_EXTERN int
pam_sm_authenticate(pam_handle_t *pamh, int flags,
Expand Down Expand Up @@ -857,21 +942,14 @@ pam_sm_authenticate(pam_handle_t *pamh, int flags,
zfs_key_config_free(&config);
return (PAM_SERVICE_ERR);
}
char *dataset = zfs_key_config_get_dataset(pamh, &config);
if (!dataset) {
pam_zfs_free();
zfs_key_config_free(&config);
return (PAM_SERVICE_ERR);
}
if (decrypt_mount(pamh, &config, dataset, token->value, B_TRUE) == -1) {
free(dataset);
pam_zfs_free();
zfs_key_config_free(&config);
return (PAM_AUTH_ERR);
}
free(dataset);

int ret = foreach_dataset(pamh, &config, auth_callback,
(void *)token->value);
pam_zfs_free();
zfs_key_config_free(&config);
if (ret < 0) {
return (PAM_AUTH_ERR);
}
return (PAM_SUCCESS);
}

Expand All @@ -884,6 +962,39 @@ pam_sm_setcred(pam_handle_t *pamh, int flags,
return (PAM_SUCCESS);
}

/* Context for password change callback */
typedef struct {
const char *old_pass;
const char *new_pass;
} chauthtok_ctx_t;

/* Callback for password change */
static int
chauthtok_callback(pam_handle_t *pamh, zfs_key_config_t *config,
const char *dataset, void *data)
{
chauthtok_ctx_t *ctx = data;
int was_loaded = is_key_loaded(pamh, dataset);
if (!was_loaded) {
int ret = decrypt_mount(pamh, config, dataset,
ctx->old_pass, B_FALSE);
if (ret == -1) {
pam_syslog(pamh, LOG_ERR,
"failed to load key for '%s' during "
"password change", dataset);
return (-1);
}
}
int ret = change_key(pamh, dataset, ctx->new_pass);
if (ret == -1) {
pam_syslog(pamh, LOG_ERR,
"failed to change key for dataset '%s'", dataset);
}
if (!was_loaded)
unmount_unload(pamh, dataset, config);
return (ret);
}

__attribute__((visibility("default")))
PAM_EXTERN int
pam_sm_chauthtok(pam_handle_t *pamh, int flags,
Expand All @@ -904,34 +1015,27 @@ pam_sm_chauthtok(pam_handle_t *pamh, int flags,
}
const pw_password_t *old_token = pw_get(pamh,
PAM_OLDAUTHTOK, OLD_PASSWORD_VAR_NAME);
{
if (pam_zfs_init(pamh) != 0) {
zfs_key_config_free(&config);
return (PAM_SERVICE_ERR);
}
char *dataset = zfs_key_config_get_dataset(pamh, &config);
if (!dataset) {
pam_zfs_free();
zfs_key_config_free(&config);
return (PAM_SERVICE_ERR);
}
if (!old_token) {
pam_syslog(pamh, LOG_ERR,
"old password from PAM stack is null");
free(dataset);
pam_zfs_free();
zfs_key_config_free(&config);
return (PAM_SERVICE_ERR);
}
if (decrypt_mount(pamh, &config, dataset,
old_token->value, B_TRUE) == -1) {
pam_syslog(pamh, LOG_ERR,
"old token mismatch");
free(dataset);
pam_zfs_free();
zfs_key_config_free(&config);
return (PAM_PERM_DENIED);
}

if (!old_token) {
pam_syslog(pamh, LOG_ERR,
"old password from PAM stack is null");
zfs_key_config_free(&config);
return (PAM_SERVICE_ERR);
}

if (pam_zfs_init(pamh) != 0) {
zfs_key_config_free(&config);
return (PAM_SERVICE_ERR);
}

/* First verify old password works for all datasets */
int ret = foreach_dataset(pamh, &config, auth_callback,
(void *)old_token->value);
if (ret < 0) {
pam_syslog(pamh, LOG_ERR, "old token mismatch");
pam_zfs_free();
zfs_key_config_free(&config);
return (PAM_PERM_DENIED);
}

if ((flags & PAM_UPDATE_AUTHTOK) != 0) {
Expand All @@ -944,41 +1048,51 @@ pam_sm_chauthtok(pam_handle_t *pamh, int flags,
pw_clear(pamh, OLD_PASSWORD_VAR_NAME);
return (PAM_SERVICE_ERR);
}
char *dataset = zfs_key_config_get_dataset(pamh, &config);
if (!dataset) {
pam_zfs_free();
zfs_key_config_free(&config);
pw_clear(pamh, OLD_PASSWORD_VAR_NAME);
pw_clear(pamh, PASSWORD_VAR_NAME);
return (PAM_SERVICE_ERR);
}
int was_loaded = is_key_loaded(pamh, dataset);
if (!was_loaded && decrypt_mount(pamh, &config, dataset,
old_token->value, B_FALSE) == -1) {
free(dataset);
pam_zfs_free();
zfs_key_config_free(&config);

chauthtok_ctx_t ctx = {
.old_pass = old_token->value,
.new_pass = token->value
};

ret = foreach_dataset(pamh, &config, chauthtok_callback, &ctx);
pam_zfs_free();
zfs_key_config_free(&config);

if (ret < 0) {
pw_clear(pamh, OLD_PASSWORD_VAR_NAME);
pw_clear(pamh, PASSWORD_VAR_NAME);
return (PAM_SERVICE_ERR);
}
int changed = change_key(pamh, dataset, token->value);
if (!was_loaded) {
unmount_unload(pamh, dataset, &config);
}
free(dataset);
pam_zfs_free();
zfs_key_config_free(&config);

if (pw_clear(pamh, OLD_PASSWORD_VAR_NAME) == -1 ||
pw_clear(pamh, PASSWORD_VAR_NAME) == -1 || changed == -1) {
pw_clear(pamh, PASSWORD_VAR_NAME) == -1) {
return (PAM_SERVICE_ERR);
}
} else {
pam_zfs_free();
zfs_key_config_free(&config);
}
return (PAM_SUCCESS);
}

/* Callback for session open - decrypt and mount */
static int
open_session_callback(pam_handle_t *pamh, zfs_key_config_t *config,
const char *dataset, void *data)
{
const char *passphrase = data;
return (decrypt_mount(pamh, config, dataset, passphrase, B_FALSE));
}

/* Callback for session close - unmount and unload */
static int
close_session_callback(pam_handle_t *pamh, zfs_key_config_t *config,
const char *dataset, void *data)
{
(void) data;
return (unmount_unload(pamh, dataset, config));
}

PAM_EXTERN int
pam_sm_open_session(pam_handle_t *pamh, int flags,
int argc, const char **argv)
Expand Down Expand Up @@ -1016,22 +1130,15 @@ pam_sm_open_session(pam_handle_t *pamh, int flags,
zfs_key_config_free(&config);
return (PAM_SERVICE_ERR);
}
char *dataset = zfs_key_config_get_dataset(pamh, &config);
if (!dataset) {
pam_zfs_free();
zfs_key_config_free(&config);
return (PAM_SERVICE_ERR);
}
if (decrypt_mount(pamh, &config, dataset,
token->value, B_FALSE) == -1) {
free(dataset);
pam_zfs_free();
zfs_key_config_free(&config);
return (PAM_SERVICE_ERR);
}
free(dataset);

int ret = foreach_dataset(pamh, &config, open_session_callback,
(void *)token->value);
pam_zfs_free();
zfs_key_config_free(&config);

if (ret < 0) {
return (PAM_SERVICE_ERR);
}
if (pw_clear(pamh, PASSWORD_VAR_NAME) == -1) {
return (PAM_SERVICE_ERR);
}
Expand Down Expand Up @@ -1071,20 +1178,15 @@ pam_sm_close_session(pam_handle_t *pamh, int flags,
zfs_key_config_free(&config);
return (PAM_SERVICE_ERR);
}
char *dataset = zfs_key_config_get_dataset(pamh, &config);
if (!dataset) {
pam_zfs_free();
zfs_key_config_free(&config);
return (PAM_SESSION_ERR);
}
if (unmount_unload(pamh, dataset, &config) == -1) {
free(dataset);
pam_zfs_free();

int ret = foreach_dataset(pamh, &config,
close_session_callback, NULL);
pam_zfs_free();

if (ret < 0) {
zfs_key_config_free(&config);
return (PAM_SESSION_ERR);
}
free(dataset);
pam_zfs_free();
}

zfs_key_config_free(&config);
Expand Down
1 change: 1 addition & 0 deletions man/Makefile.am
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Original file line number Diff line number Diff line change
Expand Up @@ -111,6 +111,7 @@ endif

if BUILD_LINUX
dist_man_MANS += \
%D%/man8/pam_zfs_key.8 \
%D%/man8/zfs-unzone.8 \
%D%/man8/zfs-zone.8
endif
Expand Down
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