From nobody Tue Jul 19 13:32:40 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 4LnKWr3MNVz4XKCQ for ; Tue, 19 Jul 2022 13:32:40 +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 4LnKWq6wWnz3Sxf for ; Tue, 19 Jul 2022 13:32:39 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (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 did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4LnKWq5h3vzLG8 for ; Tue, 19 Jul 2022 13:32:39 +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 26JDWdWd011458 for ; Tue, 19 Jul 2022 13:32:39 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 26JDWd9j011457 for bugs@FreeBSD.org; Tue, 19 Jul 2022 13:32:39 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 265311] silly mount() arguments with MNT_UPDATE and MNT_UNION can cause kernel page-fault Date: Tue, 19 Jul 2022 13:32:40 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern 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 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 ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1658237560; 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; bh=edtLY+kYRuo+eCUZA3gDvKWfycUVmFMfUqRgHhVFI0k=; b=UOecM45XD7IJNAgJ6kRs9lsWBw92XTYaraXW/+NeqenXQdx5gMYW5YUD30sT9BBYdqE1Jx /aZwN3I40cltO32HhdrZ2AYE6+rMTVCK5QuazeQXoNQ9hOpG0Q/t4frtmz6MjDOGkvnroC DmxR4Q0yRnCMNS6grLz5KSsLK9Tb+8dK2Bz+OCkD0Z2K4a9xUhaF2Fx6UR6Oug1kIZzi5D ZT2P+WtMGtRIJ8hHdMplx4aWCw2zjrMS7TGq/X+ovabocjvWL5thfsSii4bAq2mNu3crII 9O0VorTJn6qheTcyXUWuwiL6mS02t9CQtvFIS/AqN5ZpsT0d8PkV8A0lOUpRXA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1658237560; a=rsa-sha256; cv=none; b=RlEsZb70t23fR+eteP8dDVUkEzqfZIp5wyxkGs+PHwoNuHpywqX/JDvSaw/HLl9pAs2ZAb epG51Hv9/aznADfQ1xAeTRDC/2kVgmBblWe74bVD3UNSg22bH4GRSXoV5dwVjLj5xwatcs tc6EoYhdzvS3Fhbz0AarMjlVxNv/xYJ4Bn2XssNXe1aSvtPKn4lGlZwmH8vTDaQNEAvj4v 4b+qBZQYxsHTTnhJon5ClRWsC6QmdrvcGNBKFKIbPlAIDifthG4MJpSZUXo0jD4cJ1Ux+K fctQbk9SV2LtVwb51wOsnlWyfipzTK47Rr65/tCzdPJFxXG0PiOQMOKMfG1hbw== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D265311 Bug ID: 265311 Summary: silly mount() arguments with MNT_UPDATE and MNT_UNION can cause kernel page-fault Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: rtm@lcs.mit.edu This user program causes a kernel page fault in CURRENT: char data[128]; memset(data, 0, sizeof(data)); *(char **)data =3D "doesnotexist"; mount("ffs", "/", 0x10020, data); 0x10020 is MNT_UPDATE and MNT_UNION. The crash happens because the argument to VREF is zero in this code from vfs_lookup(): if ((error =3D=3D ENOENT) && (dp->v_vflag & VV_ROOT) && (dp->v_mount !=3D NULL) && (dp->v_mount->mnt_flag & MNT_UNION)) { tdp =3D dp; dp =3D dp->v_mount->mnt_vnodecovered; VREF(dp); panic: Fatal page fault at 0xffffffc0003934f4: 0x000000000001ac ... panic() at panic+0x2a page_fault_handler() at page_fault_handler+0x1a4 do_trap_supervisor() at do_trap_supervisor+0x76 cpu_exception_handler_supervisor() at cpu_exception_handler_supervisor+0x70 --- exception 13, tval =3D 0x1ac refcount_acquire_if_gt() at refcount_acquire_if_gt+0xe refcount_acquire_if_not_zero() at refcount_acquire_if_not_zero+0xc vget_prep() at vget_prep+0x14 vref() at vref+0x10 vfs_lookup() at vfs_lookup+0x374 namei() at namei+0x17e ffs_mount() at ffs_mount+0x2dc vfs_domount_update() at vfs_domount_update+0x1fa vfs_domount() at vfs_domount+0x230 vfs_donmount() at vfs_donmount+0x742 kernel_mount() at kernel_mount+0x4e ffs_cmount() at ffs_cmount+0x60 sys_mount() at sys_mount+0x17e syscallenter() at syscallenter+0xec ecall_handler() at ecall_handler+0x18 do_trap_user() at do_trap_user+0xea cpu_exception_handler_user() at cpu_exception_handler_user+0x72 --=20 You are receiving this mail because: You are the assignee for the bug.=