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* tty: Introduce some close helpers for portsAlan Cox2009-01-02
| | | | | | | Again this is a lot of common code we can unify Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Introduce a tty_port generic block_til_readyAlan Cox2009-01-02
| | | | | | | | Start sucking more commonality out of the drivers into a single piece of core code. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* isicom: redo locking to use tty port locksAlan Cox2009-01-02
| | | | | | | | This helps set the basis for moving block_til_ready into common code. We also introduce a tty_port_hangup helper as this will also be generally needed. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Pull the dtr raise into tty portAlan Cox2009-01-02
| | | | | | | | This moves another per device special out of what should be shared open wait paths into private methods Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty_port: Add a port level carrier detect operationAlan Cox2009-01-02
| | | | | | | | This is the first step to generalising the various pieces of waiting logic duplicated in all sorts of serial drivers. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Fix PPP hang under loadAlan Cox2009-01-02
| | | | | Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pty: simplify resizeAlan Cox2009-01-02
| | | | | | | | We have special case logic for resizing pty/tty pairs. We also have a per driver resize method so for the pty case we should use it. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* n_tty: Fix loss of echoed characters and remove bkl from n_ttyJoe Peterson2009-01-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fixes the loss of echoed (and other ldisc-generated characters) when the tty is stopped or when the driver output buffer is full (happens frequently for input during continuous program output, such as ^C) and removes the Big Kernel Lock from the N_TTY line discipline. Adds an "echo buffer" to the N_TTY line discipline that handles all ldisc-generated output (including echoed characters). Along with the loss of characters, this also fixes the associated loss of sync between tty output and the ldisc state when characters cannot be immediately written to the tty driver. The echo buffer stores (in addition to characters) state operations that need to be done at the time of character output (like management of the column position). This allows echo to cooperate correctly with program output, since the ldisc state remains consistent with actual characters written. Since the echo buffer code now isolates the tty column state code to the process_out* and process_echoes functions, we can remove the Big Kernel Lock (BKL) and replace it with mutex locks. Highlights are: * Handles echo (and other ldisc output) when tty driver buffer is full - continuous program output can block echo * Saves echo when tty is in stopped state (e.g. ^S) - (e.g.: ^Q will correctly cause held characters to be released for output) * Control character pairs (e.g. "^C") are treated atomically and not split up by interleaved program output * Line discipline state is kept consistent with characters sent to the tty driver * Remove the big kernel lock (BKL) from N_TTY line discipline Signed-off-by: Joe Peterson <joe@skyrush.com> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'tracing-core-for-linus' of ↵Linus Torvalds2008-12-28
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (241 commits) sched, trace: update trace_sched_wakeup() tracing/ftrace: don't trace on early stage of a secondary cpu boot, v3 Revert "x86: disable X86_PTRACE_BTS" ring-buffer: prevent false positive warning ring-buffer: fix dangling commit race ftrace: enable format arguments checking x86, bts: memory accounting x86, bts: add fork and exit handling ftrace: introduce tracing_reset_online_cpus() helper tracing: fix warnings in kernel/trace/trace_sched_switch.c tracing: fix warning in kernel/trace/trace.c tracing/ring-buffer: remove unused ring_buffer size trace: fix task state printout ftrace: add not to regex on filtering functions trace: better use of stack_trace_enabled for boot up code trace: add a way to enable or disable the stack tracer x86: entry_64 - introduce FTRACE_ frame macro v2 tracing/ftrace: add the printk-msg-only option tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp() x86, bts: correctly report invalid bts records ... Fixed up trivial conflict in scripts/recordmcount.pl due to SH bits being already partly merged by the SH merge.
| * tracing, tty: fix warnings caused by branch tracing and tty_kref_get()Ingo Molnar2008-11-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stephen Rothwell reported tht this warning started triggering in linux-next: In file included from init/main.c:27: include/linux/tty.h: In function ‘tty_kref_get’: include/linux/tty.h:330: warning: ‘______f’ is static but declared in inline function ‘tty_kref_get’ which is not static Which gcc emits for 'extern inline' functions that nevertheless define static variables. Change it to 'static inline', which is the norm in the kernel anyway. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Audit: Log TIOCSTIAl Viro2008-12-09
|/ | | | | | | | | | | | | | | | | AUDIT_TTY records currently log all data read by processes marked for TTY input auditing, even if the data was "pushed back" using the TIOCSTI ioctl, not typed by the user. This patch records all TIOCSTI calls to disambiguate the input. It generates one audit message per character pushed back; considering TIOCSTI is used very rarely, this simple solution is probably good enough. (The only program I could find that uses TIOCSTI is mailx/nail in "header editing" mode, e.g. using the ~h escape. mailx is used very rarely, and the escapes are used even rarer.) Signed-Off-By: Miloslav Trmac <mitr@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: James Morris <jmorris@namei.org>
* tty: some ICANON magic is in the wrong placesAlan Cox2008-10-13
| | | | | | | | | Move the set up on ldisc change into the ldisc Move the INQ/OUTQ cases into the driver not in shared ioctl code where it gives bogus answers for other ldisc values Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: extract the pty init time special casesAlan Cox2008-10-13
| | | | | | | | The majority of the remaining init_dev code is pty special cases. We refactor this code into the driver->install method. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Finish fixing up the init_dev interface to use ERR_PTRAlan Cox2008-10-13
| | | | | | | Original suggestion and proposal from Sukadev Bhattiprolu. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Remove more special casing and out of place codeAlan Cox2008-10-13
| | | | | | | | | Carry on pushing code out of tty_io when it belongs to other drivers. I'm not 100% happy with some of this and it will be worth revisiting some of the exports later when the restructuring work is done. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: shutdown methodAlan Cox2008-10-13
| | | | | | | | | | | | | | | | | | | Right now there are various drivers that try to use tty->count to know when they get the final close. Aristeau Rozanski showed while debugging the vt sysfs race that this isn't entirely safe. Instead of driver side tricks to work around this introduce a shutdown which is called when the tty is being destructed. This also means that the shutdown method is tied into the refcounting. Use this to rework the console close/sysfs logic. Remove lots of special case code from the tty core code. The pty code can now have a shutdown() method that replaces the special case hackery in the tree free up paths. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: the vhangup syscall is racyAlan Cox2008-10-13
| | | | | | | | We now have the infrastructure to sort this out but rather than teaching the syscall tty lock rules we move the hard work into a tty helper Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: usb-serial krefsAlan Cox2008-10-13
| | | | | | | | | | | | | Use kref in the USB serial drivers so that we don't free tty structures from under the URB receive handlers as has historically been the case if you were unlucky. This also gives us a framework for general tty drivers to use tty_port objects and refcount. Contains two err->dev_err changes merged together to fix clashes in the -next tree. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Add termioxAlan Cox2008-10-13
| | | | | | | | | | | | | | We need a way to describe the various additional modes and flow control features that random weird hardware shows up and software such as wine wants to emulate as Windows supports them. TCGETX/TCSETX and the termiox ioctl are a SYS5 extension that we might as well adopt. This patches adds the structures and the basic ioctl interfaces when the TCGETX etc defines are added for an architecture. Drivers wishing to use this stuff need to add new methods. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Add a kref countAlan Cox2008-10-13
| | | | | | | | Introduce a kref to the tty structure and use it to protect the tty->signal tty references. For now we don't introduce it for anything else. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: Reserve a line discipline number for PPSAlan Cox2008-10-13
| | | | | | | | | Add a new line discipline for "pulse per second" devices connected to a serial port. Signed-off-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: split the buffering from tty_ioAlan Cox2008-10-13
| | | | | | | | The two are basically independent chunks of code so lets split them up for readability and sanity. It also makes the API boundaries much clearer. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: remove resize window special caseAlan Cox2008-08-15
| | | | | | | | | This moves it to being a tty operation. That removes special cases and now also means that resize can be picked up by um and other non vt consoles which may have a resize operation. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Split ldisc code into its own fileAlan Cox2008-07-22
| | | | | | Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: add more tty_port fieldsAlan Cox2008-07-20
| | | | | | | Move more bits into the tty_port structure Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty.h: clean upAlan Cox2008-07-20
| | | | | | | Coding style clean up and white space tidy Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Introduce a tty_port common structureAlan Cox2008-07-20
| | | | | | | | | | | Every tty driver has its own concept of a port structure and because they all differ we cannot extract commonality. Begin fixing this by creating a structure drivers can elect to use so that over time we can push fields into this and create commonality and then introduce common methods. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Ldisc revampAlan Cox2008-07-20
| | | | | | | | | | | | Move the line disciplines towards a conventional ->ops arrangement. For the moment the actual 'tty_ldisc' struct in the tty is kept as part of the tty struct but this can then be changed if it turns out that when it all settles down we want to refcount ldiscs separately to the tty. Pull the ldisc code out of /proc and put it with our ldisc code. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix various old email addresses for dwmw2David Woodhouse2008-06-06
| | | | | | | | | Although if people have questions about ARCnet, perhaps it's _better_ for them to be mailing dwmw2@cam.ac.uk about it... Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: add throttle/unthrottle helpersAlan Cox2008-04-30
| | | | | | | | | Something Arjan suggested which allows us to clean up the code nicely Signed-off-by: Alan Cox <alan@redhat.com> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: The big operations reworkAlan Cox2008-04-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Operations are now a shared const function block as with most other Linux objects - Introduce wrappers for some optional functions to get consistent behaviour - Wrap put_char which used to be patched by the tty layer - Document which functions are needed/optional - Make put_char report success/fail - Cache the driver->ops pointer in the tty as tty->ops - Remove various surplus lock calls we no longer need - Remove proc_write method as noted by Alexey Dobriyan - Introduce some missing sanity checks where certain driver/ldisc combinations would oops as they didn't check needed methods were present [akpm@linux-foundation.org: fix fs/compat_ioctl.c build] [akpm@linux-foundation.org: fix isicom] [akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build] [akpm@linux-foundation.org: fix kgdb] Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty_io: fix remaining pid struct lockingAlan Cox2008-04-30
| | | | | | | | | | This fixes the last couple of pid struct locking failures I know about. [oleg@tv-sign.ru: clean up do_task_stat()] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* redo locking of tty->pgrpAlan Cox2008-04-30
| | | | | | | | | | | | Historically tty->pgrp and friends were pid_t and the code "knew" they were safe. The change to pid structs opened up a few races and the removal of the BKL in places made them quite hittable. We put tty->pgrp under the ctrl_lock for the tty. Signed-off-by: Alan Cox <alan@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: BKL pushdownAlan Cox2008-04-30
| | | | | | | | | | | | | | | | | - Push the BKL down into the line disciplines - Switch the tty layer to unlocked_ioctl - Introduce a new ctrl_lock spin lock for the control bits - Eliminate much of the lock_kernel use in n_tty - Prepare to (but don't yet) call the drivers with the lock dropped on the paths that historically held the lock BKL now primarily protects open/close/ldisc change in the tty layer [jirislaby@gmail.com: a couple of fixes] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [patch 1/2] audit: let userspace fully control TTY input auditingMiloslav Trmac2008-04-28
| | | | | | | | | | | | | | | | | | | Remove the code that automatically disables TTY input auditing in processes that open TTYs when they have no other TTY open; this heuristic was intended to automatically handle daemons, but it has false positives (e.g. with sshd) that make it impossible to control TTY input auditing from a PAM module. With this patch, TTY input auditing is controlled from user-space only. On the other hand, not even for daemons does it make sense to audit "input" from PTY masters; this data was produced by a program writing to the PTY slave, and does not represent data entered by the user. Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Audit: collect sessionid in netlink messagesEric Paris2008-04-28
| | | | | | | | | | Previously I added sessionid output to all audit messages where it was available but we still didn't know the sessionid of the sender of netlink messages. This patch adds that information to netlink messages so we can audit who sent netlink messages. Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* tty: Kill TTY_FLIPBUF_SIZEAlan Cox2008-02-07
| | | | | | | | | This legacy define from the old buffer code is now only used in a single power pc driver than doesn't compile anyway. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* drivers/char/tty_io.c: remove pty_semDaniel Walker2008-02-06
| | | | | | | | | | I couldn't find any users, so removing it.. Signed-off-by: Daniel Walker <dwalker@mvista.com> Acked-by: Alan Cox <alan@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [CAN]: Allocate protocol numbers for PF_CANOliver Hartkopp2008-01-28
| | | | | | | | | | This patch adds a protocol/address family number, ARP hardware type, ethernet packet type, and a line discipline number for the SocketCAN implementation. Signed-off-by: Oliver Hartkopp <oliver.hartkopp@volkswagen.de> Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* pl2303: Fix mode switching regressionAlan Cox2008-01-08
| | | | | | | | | | | | | | | Cleaning out all the incorrect 'no change made' checks for termios settings showed up a problem with the PL2303. The hardware here seems to lose sync and bits if you tell it to make no changes. This shows up with a real world application. To fix this the driver check for meaningful hardware changes is restored but doing the tests correctly and as a tty layer function so it doesn't get duplicated wrongly everywhere if other drivers turn out to need it. Signed-off-by: Alan Cox <alan@redhat.com> Tested-by: Mirko Parthey <mirko.parthey@informatik.tu-chemnitz.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [TTY]: Fix network driver interactions with TCGET/SET calls.Alan Cox2007-11-07
| | | | | | | | | | | | | | | | | | | | | | | | | | Dave Miller noted various cases where line disciplines for things like ppp go poking around in termios themselves in ways that broke with the new termios code. Rather than have them all learning about termios internals provide proper methods for this - tty_mode_ioctl() This handles all the terminal mode handling for speed/carrier etc and none of the methods are ldisc dependant so they can be called by any user - tty_perform_flush() This extracts the flush functionality and enables pppd the ppp layer to share it cleanly. The existing n_tty_ioctl code is refactored in this patch to provide the new functions and to call them itself appropriately. This patch has no (intended) behaviour changes and simply prepares for the other fixes. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tty: expose new methods needed for drivers to get termios rightAlan Cox2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds three new functions (or in one case to be more exact makes it always available) tty_termios_copy_hw Copies all the hardware settings from one termios structure to the other. This is intended for drivers that support little or no hardware setting tty_termios_encode_baud_rate Allows you to set the input and output baud rate in a termios structure. A driver is supposed to set the resulting baud rate from a request so most will want to use this function to set the resulting input and output rates to match the hardware values. Internally it knows about keeping Bxxx encoding when possible to maximise compatibility. tty_encode_baud_rate As above but for the tty's own current termios structure I suspect this will initially need some tweaking as it gets enabled by driver patches over the next few mm cycles so consider this lot -mm only for the moment so it can stabilize and end up neat before it goes to base. I've tried not to break any obscure architectures - if you get a speed you can't represent the code will print warnings on non updated termios systems but not break. Once this is merged and seems sane I've got a growing pile of driver updates to use it - notably for USB serial drivers. [akpm@linux-foundation.org: cleanups] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty.h: remove dead defineAlan Cox2007-10-17
| | | | | | | | | No longer used. TTY_FLIPBUF_SIZE will also go soon but needs a couple of other cleanups first Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* PTY: add kernel parameter to overwrite legacy pty countKay Sievers2007-10-12
| | | | | | Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* fix serial buffer memory leakAlan Cox2007-08-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch c5c34d4862e18ef07c1276d233507f540fb5a532 (tty: flush flip buffer on ldisc input queue flush) introduces a race condition which can lead to memory leaks. The problem can be triggered when tcflush() is called when data are being pushed to the line discipline driver by flush_to_ldisc(). flush_to_ldisc() releases tty->buf.lock when calling the line discipline receive_buf function. At that poing tty_buffer_flush() kicks in and sets both tty->buf.head and tty->buf.tail to NULL. When flush_to_ldisc() finishes, it restores tty->buf.head but doesn't touch tty->buf.tail. This corrups the buffer queue, and the next call to tty_buffer_request_room() will allocate a new buffer and overwrite tty->buf.head. The previous buffer is then lost forever without being released. (Thanks to Laurent for the above text, for finding, disgnosing and reporting the bug) - Use tty->flags bits for the flush status. - Wait for the flag to clear again before returning - Fix the doc error noted - Fix flush of empty queue leaving stale flushpending [akpm@linux-foundation.org: cleanup] Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Paul Fulghum <paulkf@microgate.com> Cc: Laurent Pinchart <laurentp@cse-semaphore.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Audit: add TTY input auditingMiloslav Trmac2007-07-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add TTY input auditing, used to audit system administrator's actions. This is required by various security standards such as DCID 6/3 and PCI to provide non-repudiation of administrator's actions and to allow a review of past actions if the administrator seems to overstep their duties or if the system becomes misconfigured for unknown reasons. These requirements do not make it necessary to audit TTY output as well. Compared to an user-space keylogger, this approach records TTY input using the audit subsystem, correlated with other audit events, and it is completely transparent to the user-space application (e.g. the console ioctls still work). TTY input auditing works on a higher level than auditing all system calls within the session, which would produce an overwhelming amount of mostly useless audit events. Add an "audit_tty" attribute, inherited across fork (). Data read from TTYs by process with the attribute is sent to the audit subsystem by the kernel. The audit netlink interface is extended to allow modifying the audit_tty attribute, and to allow sending explanatory audit events from user-space (for example, a shell might send an event containing the final command, after the interactive command-line editing and history expansion is performed, which might be difficult to decipher from the TTY input alone). Because the "audit_tty" attribute is inherited across fork (), it would be set e.g. for sshd restarted within an audited session. To prevent this, the audit_tty attribute is cleared when a process with no open TTY file descriptors (e.g. after daemon startup) opens a TTY. See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a more detailed rationale document for an older version of this patch. [akpm@linux-foundation.org: build fix] Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Prevent an O_NDELAY writer from blocking when a tty write is blocked by the ↵Alan Cox2007-07-16
| | | | | | | | | | | | | tty atomic writer mutex Without this a tty write could block if a previous blocking tty write was in progress on the same tty and blocked by a line discipline or hardware event. Originally found and reported by Dave Johnson. Signed-off-by: Alan Cox <alan@redhat.com> Acked-by: Dave Johnson <djohnson+linux-kernel@sw.starentnetworks.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: introduce no_tty and use it in selinuxEric W. Biederman2007-05-08
| | | | | | | | | | | | | | | | | | | | | | | | | While researching the tty layer pid leaks I found a weird case in selinux when we drop a controlling tty because of inadequate permissions we don't do the normal hangup processing. Which is a problem if it happens the session leader has exec'd something that can no longer access the tty. We already have code in the kernel to handle this case in the form of the TIOCNOTTY ioctl. So this patch factors out a helper function that is the essence of that ioctl and calls it from the selinux code. This removes the inconsistency in handling dropping of a controlling tty and who knows it might even make some part of user space happy because it received a SIGHUP it was expecting. In addition since this removes the last user of proc_set_tty outside of tty_io.c proc_set_tty is made static and removed from tty.h Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: James Morris <jmorris@namei.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] tty: update the tty layer to work with struct pidEric W. Biederman2007-02-12
| | | | | | | | | | | | | | | | | Of kernel subsystems that work with pids the tty layer is probably the largest consumer. But it has the nice virtue that the assiation with a session only lasts until the session leader exits. Which means that no reference counting is required. So using struct pid winds up being a simple optimization to avoid hash table lookups. In the long term the use of pid_nr also ensures that when we have multiple pid spaces mixed everything will work correctly. Signed-off-by: Eric W. Biederman <eric@maxwell.lnxi.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] pid: replace is_orphaned_pgrp with is_current_pgrp_orphanedEric W. Biederman2007-02-12
| | | | | | | | | | | | | | | | | | | Every call to is_orphaned_pgrp passed in process_group(current) which is racy with respect to another thread changing our process group. It didn't bite us because we were dealing with integers and the worse we would get would be a stale answer. In switching the checks to use struct pid to be a little more efficient and prepare the way for pid namespaces this race became apparent. So I simplified the calls to the more specialized is_current_pgrp_orphaned so I didn't have to worry about making logic changes to avoid the race. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>