pam-systemd: use secure_getenv() rather than getenv()

And explain why in a comment.
This commit is contained in:
Lennart Poettering 2019-02-04 10:23:43 +01:00
parent 565026b49a
commit 83d4ab5533
1 changed files with 10 additions and 3 deletions

View File

@ -327,14 +327,21 @@ static const char* getenv_harder(pam_handle_t *handle, const char *key, const ch
assert(handle);
assert(key);
/* Looks for an environment variable, preferrably in the environment block associated with the specified PAM
* handle, falling back to the process' block instead. */
/* Looks for an environment variable, preferrably in the environment block associated with the
* specified PAM handle, falling back to the process' block instead. Why check both? Because we want
* to permit configuration of session properties from unit files that invoke PAM services, so that
* PAM services don't have to be reworked to set systemd-specific properties, but these properties
* can still be set from the unit file Environment= block. */
v = pam_getenv(handle, key);
if (!isempty(v))
return v;
v = getenv(key);
/* We use secure_getenv() here, since we might get loaded into su/sudo, which are SUID. Ideally
* they'd clean up the environment before invoking foreign code (such as PAM modules), but alas they
* currently don't (to be precise, they clean up the environment they pass to their children, but
* not their own environ[]). */
v = secure_getenv(key);
if (!isempty(v))
return v;