alpine 3.6
access weakness #97

Definition:

An access weakness occurs when software does not properly implement permissions that could have unintended consequences if exploited by malicious actors. An example of this weakness is when a default username and password are set by the developer but do not get changed by the system administrator.

Warning code(s):

Ensure that umask is given most restrictive possible setting.

File Name:

rpm/src/rpm-4.13.0/sign/rpmgensig.c

Context:

The highlighted line of code below is the trigger point of this particular Alpine 3.6 access weakness.

 typedef struct sigTarget_s {
    FD_t fd;
    const char *fileName;
    off_t start;
    rpm_loff_t size;
} *sigTarget;

/*
 * There is no function for creating unique temporary fifos so create
 * unique temporary directory and then create fifo in it.
 */
static char *mkTempFifo(void)
{
    char *tmppath = NULL, *tmpdir = NULL, *fifofn = NULL;
    mode_t mode;

    tmppath = rpmExpand("%{_tmppath}", NULL);
    if (rpmioMkpath(tmppath, 0755, (uid_t) -1, (gid_t) -1))
	goto exit;


    tmpdir = rpmGetPath(tmppath, "/rpm-tmp.XXXXXX", NULL);
    mode = umask(0077);
    tmpdir = mkdtemp(tmpdir);
    umask(mode);
    if (tmpdir == NULL) {
	rpmlog(RPMLOG_ERR, _("error creating temp directory %s: %m\n"),
	    tmpdir);
	tmpdir = _free(tmpdir);
	goto exit;
    }

    fifofn = rpmGetPath(tmpdir, "/fifo", NULL);
    if (mkfifo(fifofn, 0600) == -1) {
	rpmlog(RPMLOG_ERR, _("error creating fifo %s: %m\n"), fifofn);
	fifofn = _free(fifofn);
    }

exit:
    if (fifofn == NULL && tmpdir != NULL)
	unlink(tmpdir);

    free(tmppath);
    free(tmpdir);

    return fifofn;
}

/* Delete fifo and then temporary directory in which it was located */
static int rpmRmTempFifo(const char *fn)