From nobody Fri Nov 25 12:12:31 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 4NJYdr0PKkz4hjHh for ; Fri, 25 Nov 2022 12:12:32 +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 4NJYdq4j4nz3nxK for ; Fri, 25 Nov 2022 12:12:31 +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=1669378351; 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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Fri, 25 Nov 2022 12:12:31 +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 2APCCVlW074728 for ; Fri, 25 Nov 2022 12:12:31 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 2APCCVT1074727 for bugs@FreeBSD.org; Fri, 25 Nov 2022 12:12:31 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 267987] kadmind's kadm5_ret_key_data() can leave pointers uninitialized, causing crash Date: Fri, 25 Nov 2022 12:12:31 +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=3D267987 Bug ID: 267987 Summary: kadmind's kadm5_ret_key_data() can leave pointers uninitialized, causing crash 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 #238335 text/plain mime type: Created attachment 238335 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D238335&action= =3Dedit cause kadmind's kadm5_ret_key_data() to yield an uninitialized pointer For a client kadm_chpass_with_key request, kadmind_dispatch() calls kadm5_ret_key_data() to fill key_data[] elements. kadm5_ret_key_data() ignores any errors it may encounter: kadm5_ret_t kadm5_ret_key_data(krb5_storage *sp, krb5_key_data *key) { krb5_data c; int32_t tmp; krb5_ret_int32(sp, &tmp); key->key_data_ver =3D tmp; krb5_ret_int32(sp, &tmp); key->key_data_kvno =3D tmp; krb5_ret_int32(sp, &tmp); key->key_data_type[0] =3D tmp; krb5_ret_data(sp, &c); key->key_data_length[0] =3D c.length; key->key_data_contents[0] =3D c.data; krb5_ret_int32(sp, &tmp); key->key_data_type[1] =3D tmp; krb5_ret_data(sp, &c); key->key_data_length[1] =3D c.length; key->key_data_contents[1] =3D c.data; return 0; } In particular, if krb5_ret_data() encounters the end of a too-short client message, it leaves c.data with its uninitialized value, and thus kadm5_ret_key_data() can set an element of the caller's key_data[] with invalid pointer contents, without returning an error. Later, if kadmind_dispatch() calls kadm5_free_key_data() due to some error (e.g. client message too short), the latter ends up trying to free() invalid pointers. I've attached a demo; it expects the user to have run kinit. # valgrind /usr/libexec/kadmind --debug & # cc kadmind17a.c -lkrb5 # ./a.out 2022-11-25T06:50:53 root@EXAMPLE.ORG: CHPASS_WITH_KEY @ =3D=3D11284=3D=3D Invalid free() / delete / delete[] / realloc() =3D=3D11284=3D=3D at 0x484E83C: free (in /usr/local/libexec/valgrind/vgpreload_memcheck-amd64-freebsd.so) =3D=3D11284=3D=3D by 0x48631BB: kadm5_free_key_data (in /usr/lib/libkadm= 5srv.so.11) =3D=3D11284=3D=3D by 0x112569: ??? (in /usr/libexec/kadmind) =3D=3D11284=3D=3D by 0x1129A8: ??? (in /usr/libexec/kadmind) =3D=3D11284=3D=3D by 0x10D1DC: ??? (in /usr/libexec/kadmind) =3D=3D11284=3D=3D by 0x4823007: ??? =3D=3D11284=3D=3D Address 0x5b77340 is 0 bytes after a block of size 0 fre= e'd =3D=3D11284=3D=3D at 0x484E83C: free (in /usr/local/libexec/valgrind/vgpreload_memcheck-amd64-freebsd.so) =3D=3D11284=3D=3D by 0x48631AE: kadm5_free_key_data (in /usr/lib/libkadm= 5srv.so.11) =3D=3D11284=3D=3D by 0x112569: ??? (in /usr/libexec/kadmind) =3D=3D11284=3D=3D by 0x1129A8: ??? (in /usr/libexec/kadmind) =3D=3D11284=3D=3D by 0x10D1DC: ??? (in /usr/libexec/kadmind) =3D=3D11284=3D=3D by 0x4823007: ??? =3D=3D11284=3D=3D Block was alloc'd at =3D=3D11284=3D=3D at 0x484CBC4: malloc (in /usr/local/libexec/valgrind/vgpreload_memcheck-amd64-freebsd.so) =3D=3D11284=3D=3D by 0x48E1B74: krb5_data_alloc (in /usr/lib/libkrb5.so.= 11) =3D=3D11284=3D=3D by 0x490B231: krb5_ret_data (in /usr/lib/libkrb5.so.11) =3D=3D11284=3D=3D by 0x4865C6D: kadm5_ret_key_data (in /usr/lib/libkadm5= srv.so.11) =3D=3D11284=3D=3D by 0x1123D7: ??? (in /usr/libexec/kadmind) =3D=3D11284=3D=3D by 0x1129A8: ??? (in /usr/libexec/kadmind) =3D=3D11284=3D=3D by 0x10D1DC: ??? (in /usr/libexec/kadmind) =3D=3D11284=3D=3D by 0x4823007: ??? --=20 You are receiving this mail because: You are the assignee for the bug.=