Re: file_type_auto_trans is not sufficient

[Ivan Gyurdiev <ivg2@xxxxxxxxxxx>]

> setfscreatecon takes precedence.

...on second thought this interface doesn't work at all - 
apps call higher level functions for portability - the C
standard functions (fopen...), glib (g_mkdir).

Maybe just add:

/* Performs a context match, and changes the file creation context.
 * On success, returns the old context. On failure, returns NULL.
 * The context returned must be freed with freecon() */

security_context_t switch_context(const char* pathname, mode_t mode) {
        security_context_t prev_ctx = NULL;
        security_context_t tmp_ctx = NULL;

        /* Attempt to get the current context. */
        if (getfscreatecon(&prev_ctx) < 0)
                return NULL;

        /* Attempt a match. */
        if (matchpathcon(pathname, mode, &tmp_ctx) >= 0) {
                if (setfscreatecon(tmp_ctx) < 0) {
                        freecon(tmp_ctx);
                        freecon(prev_ctx);
                        return NULL;
                }
                freecon(tmp_ctx);
        }

        return prev_ctx;
}

...and then do this in every app that needs it, replacing
mkdir with the appropriate function. This is annoying.... 
but I can't think how else to write a better interface.

/* Performs a mkdir call, and sets the context of the directory
 * being created, according to matchpathcon. On SElinux failure
 * returns -1. Otherwise, returns the usual mkdir status. */

int mkdir_restorecon(const char *pathname, mode_t mode) {
        security_context_t prev_ctx = NULL;
        int status;

        if (is_selinux_enabled()) {
                prev_ctx = switch_context(pathname, mode);

                if ((prev_ctx != NULL) && security_getenforce())
                        return -1;
        }

        status = mkdir(pathname, mode);

        if (prev_ctx != NULL) {
                setfscreatecon(prev_ctx);
                freecon(prev_ctx);
        }

        return status;
}

-- 
Ivan Gyurdiev <ivg2@xxxxxxxxxxx>
Cornell University


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