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Commit aff7ed48 authored by Ondrej Mosnacek's avatar Ondrej Mosnacek Committed by Paul Moore
Browse files

selinux: log raw contexts as untrusted strings 



These strings may come from untrusted sources (e.g. file xattrs) so they
need to be properly escaped.

Reproducer:
    # setenforce 0
    # touch /tmp/test
    # setfattr -n security.selinux -v 'kuřecí řízek' /tmp/test
    # runcon system_u:system_r:sshd_t:s0 cat /tmp/test
    (look at the generated AVCs)

Actual result:
    type=AVC [...] trawcon=kuřecí řízek

Expected result:
    type=AVC [...] trawcon=6B75C5996563C3AD20C599C3AD7A656B

Fixes: fede1483 ("selinux: log invalid contexts in AVCs")
Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: default avatarOndrej Mosnacek <omosnace@redhat.com>
Acked-by: default avatarRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent 05174c95

security/selinux/avc.c

+8 −2
Original line number Diff line number Diff line
@@ -739,14 +739,20 @@ static void avc_audit_post_callback(struct audit_buffer *ab, void *a) 
	rc = security_sid_to_context_inval(sad->state, sad->ssid, &scontext,

					   &scontext_len);

	if (!rc && scontext) {

		audit_log_format(ab, " srawcon=%s", scontext);

		if (scontext_len && scontext[scontext_len - 1] == '\0')

			scontext_len--;

		audit_log_format(ab, " srawcon=");

		audit_log_n_untrustedstring(ab, scontext, scontext_len);

		kfree(scontext);

	}



	rc = security_sid_to_context_inval(sad->state, sad->tsid, &scontext,

					   &scontext_len);

	if (!rc && scontext) {

		audit_log_format(ab, " trawcon=%s", scontext);

		if (scontext_len && scontext[scontext_len - 1] == '\0')

			scontext_len--;

		audit_log_format(ab, " trawcon=");

		audit_log_n_untrustedstring(ab, scontext, scontext_len);

		kfree(scontext);

	}

}