From nobody Mon Nov 21 23:13:31 2022 X-Original-To: bugs@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4NGNVN0gzJz4hpZy for ; Mon, 21 Nov 2022 23:13:32 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4NGNVM4w4Bz4FTj for ; Mon, 21 Nov 2022 23:13:31 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1669072411; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; 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Mon, 21 Nov 2022 23:13:31 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 2ALNDVQv032123 for ; Mon, 21 Nov 2022 23:13:31 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 2ALNDV4L032122 for bugs@FreeBSD.org; Mon, 21 Nov 2022 23:13:31 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 267912] kadmind dereferences NULL if client sends mangled realm message Date: Mon, 21 Nov 2022 23:13:31 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: bin X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: rtm@lcs.mit.edu X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter attachments.mimetype attachments.created Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Bug reports List-Archive: https://lists.freebsd.org/archives/freebsd-bugs List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-bugs@freebsd.org MIME-Version: 1.0 X-ThisMailContainsUnwantedMimeParts: N https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D267912 Bug ID: 267912 Summary: kadmind dereferences NULL if client sends mangled realm message Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: bin Assignee: bugs@FreeBSD.org Reporter: rtm@lcs.mit.edu Attachment #238235 text/plain mime type: Created attachment 238235 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D238235&action= =3Dedit crash kadmind with a missing realm string kadmind's handle_v5() reads a client message that can optionally contain the realm name: if(kadm_version =3D=3D 1) { krb5_data params; ret =3D krb5_read_priv_message(contextp, ac, &fd, ¶ms); if(ret) krb5_err(contextp, 1, ret, "krb5_read_priv_message"); _kadm5_unmarshal_params(contextp, ¶ms, &realm_params); } If the client sends a mask containing KADM5_CONFIG_REALM, but the client's message stops too early, realm_params.mask will have that bit set, but realm_params.realm will be NULL. _kadm5_unmarshal_params() returns an error in this case, but handle_b5() doesn't check its return value. Later, _kadm5_s_init_context() says #define is_set(M) (params && params->mask & KADM5_CONFIG_ ## M) if(is_set(REALM)) (*ctx)->config.realm =3D strdup(params->realm); The bit is set, so strdup() crashes. I've attached a demo program. It must be run on a system with kdc and kadmind running, and the user must have tickets. Here's a backtrace: #0 strlen (str=3D) at /usr/rtm/symbsd/src/lib/libc/string/strlen.c:94 #1 0x00000006afe04f48 in strdup (str=3D0x0) at /usr/rtm/symbsd/src/lib/libc/string/strdup.c:48 #2 0x00000006ac04b270 in _kadm5_s_init_context (ctx=3D0x6aa2d9fd8,=20 params=3D0x6aa2da030, context=3D0x6b9381e10) at /usr/rtm/symbsd/src/crypto/heimdal/lib/kadm5/context_s.c:153 #3 0x00000006ac04c90a in kadm5_s_init_with_context (context=3D0x0,=20 client_name=3D0x6b93cec50 "root@EXAMPLE.ORG", service_name=3D,=20 realm_params=3D0x6afcc8fd8, struct_version=3D,=20 api_version=3D, server_handle=3D0x6aa2da078) at /usr/rtm/symbsd/src/crypto/heimdal/lib/kadm5/init_s.c:50 #4 0x00000006ac04c8dc in kadm5_s_init_with_password_ctx (context=3D0x0,=20 client_name=3D0x6afcc8fd8 "\377\376\376\376\376\376\376\376environmUUUUUUUU\333\064\266=C3=97\336\033= CaCoc\247\207\322?hfffffff\213\200",=20 password=3D, service_name=3D, realm_param= s=3D0x0,=20 struct_version=3D, api_version=3D,=20 server_handle=3D0x186db) at /usr/rtm/symbsd/src/crypto/heimdal/lib/kadm5/init_s.c:104 #5 0x0000000629fe5d72 in handle_v5 (contextp=3D,=20 keytab=3D, fd=3D) at /usr/rtm/symbsd/src/crypto/heimdal/kadmin/server.c:539 #6 0x0000000629fe5c96 in kadmind_loop (contextp=3D0x6b9381e10, --=20 You are receiving this mail because: You are the assignee for the bug.=