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e2e3d0a401
mode. This addresses a well-known race condition that can cause servers to hang in accept(). The relevant case is when somebody connects to the server and then immediately kills the connection by sending a TCP reset. On the server this causes select to report a ready condition on the socket, after which the accept call blocks because there is no longer any pending connection to accept. In -current there is already a work-around for this in the kernel. It was merged into -stable some time ago, but then David Greenman reverted it because it seemed to be causing a socket leak in some cases. (See uipc_socket.c revision 1.51.2.3.) Hence this userland fix is needed in -stable, and I plan to merge it into that branch soon because it fixes a potential DoS attack. It may also be needed in -current if the suspected socket leak turns out to be real. In any case, after thinking it over I believe the fix belongs in userland. An application shouldn't assume that a ready return from select guarantees that the subsequent I/O operation cannot block. A lot can happen between the select and the accept. A similar fix should most likely be applied to the Unix domain socket transport too. Submitted by: peter Reviewed by: jdp |
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| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| kerberosIV | ||
| lib | ||
| libexec | ||
| release | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| Makefile | ||
| Makefile.inc0 | ||
| Makefile.inc1 | ||
| Makefile.upgrade | ||
| README | ||
| UPDATING | ||
This is the top level of the FreeBSD source directory. This file was last revised on: $FreeBSD$ For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information). The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel and the contents of /etc. Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags. Building a kernel with config(8) is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/handbook/kernelconfig.html And in the config(8) man page. The sample kernel configuration files reside in the sys/i386/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file LINT contains entries for all possible devices, not just those commonly used, and is meant more as a general reference than an actual kernel configuration file (a kernel built from it wouldn't even run). Source Roadmap: --------------- bin System/User commands. contrib Packages contributed by 3rd parties. crypto Export controlled stuff (see crypto/README). etc Template files for /etc games Amusements. gnu Various commands and libraries under the GNU Public License. Please see gnu/COPYING* for more information. include System include files. kerberosIV Kerberos package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. sbin System commands. secure DES and DES-related utilities - NOT FOR EXPORT! share Shared resources. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/handbook/synching.html