From owner-freebsd-bugs@freebsd.org Sat Apr 10 22:05:22 2021 Return-Path: Delivered-To: freebsd-bugs@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 2C3B15D95CF for ; Sat, 10 Apr 2021 22:05:22 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.nyi.freebsd.org (mailman.nyi.freebsd.org [IPv6:2610:1c1:1:606c::50:13]) by mx1.freebsd.org (Postfix) with ESMTP id 4FHpw20ZxMz4VXj for ; Sat, 10 Apr 2021 22:05:22 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.nyi.freebsd.org (Postfix) id 120DA5D95CE; Sat, 10 Apr 2021 22:05:22 +0000 (UTC) Delivered-To: bugs@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 11D0E5D9737 for ; Sat, 10 Apr 2021 22:05:22 +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 4FHpw1716Kz4VXh for ; Sat, 10 Apr 2021 22:05:21 +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 E383618AEF for ; Sat, 10 Apr 2021 22:05:21 +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 13AM5LS7047414 for ; Sat, 10 Apr 2021 22:05:21 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 13AM5LVf047413 for bugs@FreeBSD.org; Sat, 10 Apr 2021 22:05:21 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 254964] Integer overflow in ffs_setextattr() could lead to a kernel heap overflow Date: Sat, 10 Apr 2021 22:05:22 +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 Many People X-Bugzilla-Who: cutesmilee.research@protonmail.com 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 MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 10 Apr 2021 22:05:22 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D254964 Bug ID: 254964 Summary: Integer overflow in ffs_setextattr() could lead to a kernel heap overflow Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Many People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: cutesmilee.research@protonmail.com ffs_setextattr() is used to set a named attribute to an ffs vfs. the problem is that it takes some user controlled data, the interesting ones are: ap->a_name (arbitrary user string, not checked), and ip->i_ea_len (unsigned int), which also isn't checked. the function uses ip->i_ea_len + ealength (which is 7 + strlen(ap->a_name))= for allocating a buffer, after that user-controlled data are copied to the buff= er using ip->i_ea_len. providing an INT_MAX ip->i_ea_len + 2^32 + 2 long string will cause an inte= ger overflow, and the buffer in the heap will be 1 byte, but the bcopy will copy 2^32 bytes to the buffer. this should be reachable from an unprivileged user (since extattr_check_cre= d() doesn't require root if the attrnamespace is set to EXTATTR_NAMESPACE_USER), but seems to be difficult to exploit, since you'd need 4GBs of ram (for the long string) just to perform the 2^32 heap overflow, an exploitable overflow will probably take even more memory. --=20 You are receiving this mail because: You are the assignee for the bug.=