From owner-freebsd-current@freebsd.org Mon Oct 7 16:48:21 2019 Return-Path: Delivered-To: freebsd-current@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 79BDA133D26 for ; Mon, 7 Oct 2019 16:48:21 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [IPv6:2610:1c1:1:606c::24b:4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 46n5yY2f70z4Gmt; Mon, 7 Oct 2019 16:48:21 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from John-Baldwins-MacBook-Pro-4.local (ralph.baldwin.cx [66.234.199.215]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) (Authenticated sender: jhb) by smtp.freebsd.org (Postfix) with ESMTPSA id CC3361080; Mon, 7 Oct 2019 16:48:20 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Subject: Re: ktrace/kdump give incorrect message on unlinkat() failure due to capabilities To: Sergey Kandaurov , Ryan Stone Cc: FreeBSD Current References: <20190925173338.lvlg4cstdjcwwbtm@MacBook-Air.local> From: John Baldwin Openpgp: preference=signencrypt Autocrypt: addr=jhb@FreeBSD.org; keydata= mQGiBETQ+XcRBADMFybiq69u+fJRy/0wzqTNS8jFfWaBTs5/OfcV7wWezVmf9sgwn8TW0Dk0 c9MBl0pz+H01dA2ZSGZ5fXlmFIsee1WEzqeJzpiwd/pejPgSzXB9ijbLHZ2/E0jhGBcVy5Yo /Tw5+U/+laeYKu2xb0XPvM0zMNls1ah5OnP9a6Ql6wCgupaoMySb7DXm2LHD1Z9jTsHcAQMD /1jzh2BoHriy/Q2s4KzzjVp/mQO5DSm2z14BvbQRcXU48oAosHA1u3Wrov6LfPY+0U1tG47X 1BGfnQH+rNAaH0livoSBQ0IPI/8WfIW7ub4qV6HYwWKVqkDkqwcpmGNDbz3gfaDht6nsie5Z pcuCcul4M9CW7Md6zzyvktjnbz61BADGDCopfZC4of0Z3Ka0u8Wik6UJOuqShBt1WcFS8ya1 oB4rc4tXfSHyMF63aPUBMxHR5DXeH+EO2edoSwViDMqWk1jTnYza51rbGY+pebLQOVOxAY7k do5Ordl3wklBPMVEPWoZ61SdbcjhHVwaC5zfiskcxj5wwXd2E9qYlBqRg7QeSm9obiBCYWxk d2luIDxqaGJARnJlZUJTRC5vcmc+iGAEExECACAFAkTQ+awCGwMGCwkIBwMCBBUCCAMEFgID AQIeAQIXgAAKCRBy3lIGd+N/BI6RAJ9S97fvbME+3hxzE3JUyUZ6vTewDACdE1stFuSfqMvM jomvZdYxIYyTUpC5Ag0ERND5ghAIAPwsO0B7BL+bz8sLlLoQktGxXwXQfS5cInvL17Dsgnr3 1AKa94j9EnXQyPEj7u0d+LmEe6CGEGDh1OcGFTMVrof2ZzkSy4+FkZwMKJpTiqeaShMh+Goj XlwIMDxyADYvBIg3eN5YdFKaPQpfgSqhT+7El7w+wSZZD8pPQuLAnie5iz9C8iKy4/cMSOrH YUK/tO+Nhw8Jjlw94Ik0T80iEhI2t+XBVjwdfjbq3HrJ0ehqdBwukyeJRYKmbn298KOFQVHO EVbHA4rF/37jzaMadK43FgJ0SAhPPF5l4l89z5oPu0b/+5e2inA3b8J3iGZxywjM+Csq1tqz hltEc7Q+E08AAwUIAL+15XH8bPbjNJdVyg2CMl10JNW2wWg2Q6qdljeaRqeR6zFus7EZTwtX sNzs5bP8y51PSUDJbeiy2RNCNKWFMndM22TZnk3GNG45nQd4OwYK0RZVrikalmJY5Q6m7Z16 4yrZgIXFdKj2t8F+x613/SJW1lIr9/bDp4U9tw0V1g3l2dFtD3p3ZrQ3hpoDtoK70ioIAjjH aIXIAcm3FGZFXy503DOA0KaTWwvOVdYCFLm3zWuSOmrX/GsEc7ovasOWwjPn878qVjbUKWwx Q4QkF4OhUV9zPtf9tDSAZ3x7QSwoKbCoRCZ/xbyTUPyQ1VvNy/mYrBcYlzHodsaqUDjHuW+I SQQYEQIACQUCRND5ggIbDAAKCRBy3lIGd+N/BCO8AJ9j1dWVQWxw/YdTbEyrRKOY8YZNwwCf afMAg8QvmOWnHx3wl8WslCaXaE8= Message-ID: Date: Mon, 7 Oct 2019 09:48:16 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20190925173338.lvlg4cstdjcwwbtm@MacBook-Air.local> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Oct 2019 16:48:21 -0000 On 9/25/19 10:33 AM, Sergey Kandaurov wrote: > On Sat, Sep 21, 2019 at 08:43:58PM -0400, Ryan Stone wrote: >> I have written a short test program that runs unlinkat(2) in >> capability mode and fails due to not having the write capabilities: >> >> https://people.freebsd.org/~rstone/src/unlink.c >> >> If I run the binary under ktrace and look at the kdump output, it >> gives the following incorrect output: >> >> 43775 unlink CALL unlinkat(0x3,0x7fffffffe995,0) >> 43775 unlink NAMI "from.QAUlAA0" >> 43775 unlink CAP operation requires CAP_LOOKUP, descriptor holds CAP_LOOKUP >> 43775 unlink RET unlinkat -1 errno 93 Capabilities insufficient >> >> The message should instead say that the operation requires >> CAP_UNLINKAT. Looking at sys/capsicum.h, I suspect that the problem >> is related to the strange definition of CAP_UNLINKAT: >> >> #define CAP_UNLINKAT (CAP_LOOKUP | 0x0000000010000000ULL) > > FYI, with this grep it was able to decode capabilities. > > Index: lib/libsysdecode/mktables > =================================================================== > --- lib/libsysdecode/mktables (revision 352685) > +++ lib/libsysdecode/mktables (working copy) > @@ -157,7 +157,7 @@ > gen_table "sigcode" "SI_[A-Z]+[[:space:]]+0(x[0-9abcdef]+)?" "sys/signal.h" > gen_table "umtxcvwaitflags" "CVWAIT_[A-Z_]+[[:space:]]+0x[0-9]+" "sys/umtx.h" > gen_table "umtxrwlockflags" "URWLOCK_PREFER_READER[[:space:]]+0x[0-9]+" "sys/umtx.h" > -gen_table "caprights" "CAP_[A-Z_]+[[:space:]]+CAPRIGHT\([0-9],[[:space:]]+0x[0-9]{16}ULL\)" "sys/capsicum.h" > +gen_table "caprights" "CAP_[A-Z_]+[[:space:]]+(CAPRIGHT|[()A-Z_|[:space:]]+CAP_LOOKUP)" "sys/capsicum.h" > gen_table "sctpprpolicy" "SCTP_PR_SCTP_[A-Z_]+[[:space:]]+0x[0-9]+" "netinet/sctp_uio.h" "SCTP_PR_SCTP_ALL" > gen_table "cmsgtypesocket" "SCM_[A-Z_]+[[:space:]]+0x[0-9]+" "sys/socket.h" > if [ -e "${include_dir}/x86/sysarch.h" ]; then CAP_SEEK and CAP_MMAP_X might also be subject to this. However, I'm not quite understanding the regex, or at least why the modified portion of the regex isn't something like this: (CAPRIGHT\(|\(CAP_LOOKUP) That is, you currently have [()A-Z_|[:space:]]+ for an expression that I think will only ever match a single '(' character. A more general form that might work for CAP_SEEK and CAP_MMAP_X might be to match on 'CAP_ | 0x