- 26 Jun, 2006 40 commits
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Oleg Nesterov authored
first_tid: /* If nr exceeds the number of threads there is nothing todo */ if (nr) { if (nr >= get_nr_threads(leader)) goto done; } This is not reliable: sub-threads can exit after this check, so the 'for' loop below can overlap and proc_task_readdir() can return an already filldir'ed dirents. for (; pos && pid_alive(pos); pos = next_thread(pos)) { if (--nr > 0) continue; Off-by-one error, will return 'leader' when nr == 1. This patch tries to fix these problems and simplify the code. Signed-off-by:Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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Eric W. Biederman authored
This is just like my previous removal of tasklist_lock from first_tgid, and next_tgid. It simply had to wait until it was rcu safe to walk the thread list. This should be the last instance of the tasklist_lock in proc. So user processes should not be able to influence the tasklist lock hold times. Signed-off-by:
Eric W. Biederman <ebiederm@xmission.com> Signed-off-by:
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Eric W. Biederman authored
In process of getting proc_fd_access_allowed to work it has developed a few warts. In particular the special case that always allows introspection and the special case to allow inspection of kernel threads. The special case for introspection is needed for /proc/self/mem. The special case for kernel threads really should be overridable by security modules. So consolidate these checks into ptrace.c:may_attach(). The check to always allow introspection is trivial. The check to allow access to kernel threads, and zombies is a little trickier. mem_read and mem_write already verify an mm exists so it isn't needed twice. proc_fd_access_allowed only doesn't want a check to verify task->mm exits, s it prevents all access to kernel threads. So just move the task->mm check into ptrace_attach where it is needed for practical reasons. I did a quick audit and none of the security modules in the kernel seem to care if they are passed a task without an mm into security_ptrace. So the above move should be safe and it allows security modules to come up with more restrictive policy. Signed-off-by:
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Eric W. Biederman authored
Since 2.2 we have been doing a chroot check to see if it is appropriate to return a read or follow one of these magic symlinks. The chroot check was asking a question about the visibility of files to the calling process and it was actually checking the destination process, and not the files themselves. That test was clearly bogus. In my first pass through I simply fixed the test to check the visibility of the files themselves. That naive approach to fixing the permissions was too strict and resulted in cases where a task could not even see all of it's file descriptors. What has disturbed me about relaxing this check is that file descriptors are per-process private things, and they are occasionaly used a user space capability tokens. Looking a little farther into the symlink path on /proc I did find userid checks and a check for capability (CAP_DAC_OVERRIDE) so there were permissions checking this. But I was still concerned about privacy. Besides /proc there is only one other way to find out this kind of information, and that is ptrace. ptrace has been around for a long time and it has a well established security model. So after thinking about it I finally realized that the permission checks that make sense are the permission checks applied to ptrace_attach. The checks are simple per process, and won't cause nasty surprises for people coming from less capable unices. Unfortunately there is one case that the current ptrace_attach test does not cover: Zombies and kernel threads. Single stepping those kinds of processes is impossible. Being able to see which file descriptors are open on these tasks is important to lsof, fuser and friends. So for these special processes I made the rule you can't find out unless you have CAP_SYS_PTRACE. These proc permission checks should now conform to the principle of least surprise. As well as using much less code to implement :) Signed-off-by:
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Eric W. Biederman authored
The code doesn't need to sleep to when making this check so I can just do the comparison and not worry about the reference counts. TODO: While looking at this I realized that my original cleanup did not push the permission check far enough down into the stack. The call of proc_check_dentry_visible needs to move out of the generic proc readlink/follow link code and into the individual get_link instances. Otherwise the shared resources checks are not quite correct (shared files_struct does not require a shared fs_struct), and there are races with unshare. Signed-off-by:
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Eric W. Biederman authored
Incrementally update my proc-dont-lock-task_structs-indefinitely patches so that they work with struct pid instead of struct task_ref. Mostly this is a straight 1-1 substitution. Signed-off-by:
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Eric W. Biederman authored
Every inode in /proc holds a reference to a struct task_struct. If a directory or file is opened and remains open after the the task exits this pinning continues. With 8K stacks on a 32bit machine the amount pinned per file descriptor is about 10K. Normally I would figure a reasonable per user process limit is about 100 processes. With 80 processes, with a 1000 file descriptors each I can trigger the 00M killer on a 32bit kernel, because I have pinned about 800MB of useless data. This patch replaces the struct task_struct pointer with a pointer to a struct task_ref which has a struct task_struct pointer. The so the pinning of dead tasks does not happen. The code now has to contend with the fact that the task may now exit at any time. Which is a little but not muh more complicated. With this change it takes about 1000 processes each opening up 1000 file descriptors before I can trigger the OOM killer. Much better. [mlp@google.com: task_mmu small fixes] Signed-off-by:
Prasanna Meda <mlp@google.com> Signed-off-by:
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Eric W. Biederman authored
Currently in /proc at several different places we define buffers to hold a process id, or a file descriptor . In most of them we use either a hard coded number or a different define. Modify them all to use PROC_NUMBUF, so the code has a chance of being maintained. Signed-off-by:
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Eric W. Biederman authored
Like the bug Oleg spotted in first_tid there was also a small off by one error in first_tgid, when a seek was done on the /proc directory. This fixes that and changes the code structure to make it a little more obvious what is going on. Signed-off-by:
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Eric W. Biederman authored
Since we no longer need the tasklist_lock for get_task_struct the lookup methods no longer need the tasklist_lock. This just depends on my previous patch that makes get_task_struct() rcu safe. Signed-off-by:
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Eric W. Biederman authored
We don't need the tasklist_lock to safely iterate through processes anymore. This depends on my previous to task patches that make get_task_struct rcu safe, and that make next_task() rcu safe. I haven't gotten first_tid/next_tid yet only because next_thread is missing an rcu_dereference. Signed-off-by:
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Eric W. Biederman authored
There are a couple of problems this patch addresses. - /proc/<tgid>/task currently does not work correctly if you stop reading in the middle of a directory. - /proc/ currently requires a full pass through the task list with the tasklist lock held, to determine there are no more processes to read. - The hand rolled integer to string conversion does not properly running out of buffer space. - We seem to be batching reading of pids from the tasklist without reason, and complicating the logic of the code. This patch addresses that by changing how tasks are processed. A first_<task_type> function is built that handles restarts, and a next_<task_type> function is built that just advances to the next task. first_<task_type> when it detects a restart usually uses find_task_by_pid. If that doesn't work because there has been a seek on the directory, or we have already given a complete directory listing, it first checks the number tasks of that type, and only if we are under that count does it walk through all of the tasks to find the one we are interested in. The code that fills in the directory is simpler because there is only a single for loop. The hand rolled integer to string conversion is replaced by snprintf which should handle the the out of buffer case correctly. Signed-off-by:
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Eric W. Biederman authored
proc_lookup and task exiting are not synchronized, although some of the previous code may have suggested that. Every time before we reuse a dentry namei.c calls d_op->derevalidate which prevents us from reusing a stale dcache entry. Unfortunately it does not prevent us from returning a stale dcache entry. This race has been explicitly plugged in proc_pid_lookup but there is nothing to confine it to just that proc lookup function. So to prevent the race I call revalidate explictily in all of the proc lookup functions after I call d_add, and report an error if the revalidate does not succeed. Years ago Al Viro did something similar but those changes got lost in the churn. Signed-off-by:
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Eric W. Biederman authored
To keep the dcache from filling up with dead /proc entries we flush them on process exit. However over the years that code has gotten hairy with a dentry_pointer and a lock in task_struct and misdocumented as a correctness feature. I have rewritten this code to look and see if we have a corresponding entry in the dcache and if so flush it on process exit. This removes the extra fields in the task_struct and allows me to trivially handle the case of a /proc/<tgid>/task/<pid> entry as well as the current /proc/<pid> entries. Signed-off-by:
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Eric W. Biederman authored
All of the functions for proc_maps_operations are already defined in task_mmu.c so move the operations structure to keep the functionality together. Since task_nommu.c implements a dummy version of /proc/<pid>/maps give it a simplified version of proc_maps_operations that it can modify to best suit its needs. Signed-off-by:
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Eric W. Biederman authored
Use getattr to get an accurate link count when needed. This is cheaper and more accurate than trying to derive it by walking the thread list of a process. Especially as it happens when needed stat instead of at readdir time. Signed-off-by:
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Eric W. Biederman authored
Long ago and far away in 2.2 we started checking to ensure the files we displayed in /proc were visible to the current process. It was an unsophisticated time and no one was worried about functions full of FIXMES in a stable kernel. As time passed the function became sacred and was enshrined in the shrine of how things have always been. The fixes came in but only to keep the function working no one really remembering or documenting why we did things that way. The intent and the functionality make a lot of sense. Don't let /proc be an access point for files a process can see no other way. The implementation however is completely wrong. We are currently checking the root directories of the two processes, we are not checking the actual file descriptors themselves. We are strangely checking with a permission method instead of just when we use the data. This patch fixes the logic to actually check the file descriptors and make a note that implementing a permission method for this part of /proc almost certainly indicates a bug in the reasoning. Signed-off-by:
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Eric W. Biederman authored
The inode operations only exist to support the proc_permission function. Currently mem_read and mem_write have all the same permission checks as ptrace. The fs check makes no sense in this context, and we can trivially get around it by calling ptrace. So simply the code by killing the strange weird case. Signed-off-by:
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Eric W. Biederman authored
First we can access every /proc/<tgid>/task/<pid> directory as /proc/<pid> so proc_task_permission is not usefully limiting visibility. Second having related filesystems information should have nothing to do with process visibility. kill does not implement any checks like that. Signed-off-by:
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Eric W. Biederman authored
The sole renaming use of proc_inode.type is to discover the file descriptor number, so just store the file descriptor number and don't wory about processing this field. This removes any /proc limits on the maximum number of file descriptors, and clears the path to make the hard coded /proc inode numbers go away. Signed-off-by:
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Eric W. Biederman authored
Currently in /proc if the task is dumpable all of files are owned by the tasks effective users. Otherwise the files are owned by root. Unless it is the /proc/<tgid>/ or /proc/<tgid>/task/<pid> directory in that case we always make the directory owned by the effective user. However the special case for directories is pointless except as a way to read the effective user, because the permissions on both of those directories are world readable, and executable. /proc/<tgid>/status provides a much better way to read a processes effecitve userid, so it is silly to try to provide that on the directory. So this patch simplifies the code by removing a pointless special case and gets us one step closer to being able to remove the hard coded /proc inode numbers. Signed-off-by:
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Eric W. Biederman authored
The removed fields are already set by proc_alloc_inode. Initializing them in proc_alloc_inode implies they need it for proper cleanup. At least ei->pde was not set on all paths making it look like proc_alloc_inode was buggy. So just remove the redundant assignments. Signed-off-by:
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Eric W. Biederman authored
We already call everything except do_proc_readlink outside of the BKL in proc_pid_followlink, and there appears to be nothing in do_proc_readlink that needs any special protection. So remove this leftover from one of the BKL cleanup efforts. Signed-off-by:
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Eric W. Biederman authored
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Herbert Xu authored
I noticed recently that my CONFIG_CRYPTO_MD5 turned into a y again instead of m. It turns out that CONFIG_NFSD_V4 is selecting it to be y even though I've chosen to compile nfsd as a module. In general when we have a bool sitting under a tristate it is better to select things you need from the tristate rather than the bool since that allows the things you select to be modules. The following patch does it for nfsd. Signed-off-by:
Herbert Xu <herbert@gondor.apana.org.au> Cc: Neil Brown <neilb@suse.de> Signed-off-by:
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Hansjoerg Lipp authored
Add the IOCTLs of the Gigaset drivers to compat_ioctl.h in order to make them available for 32 bit programs on 64 bit platforms. Please merge. Signed-off-by:
Hansjoerg Lipp <hjlipp@web.de> Acked-by:
Tilman Schmidt <tilman@imap.cc> Cc: Karsten Keil <kkeil@suse.de> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by:
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Tilman Schmidt authored
The following patch to the common part of the Siemens Gigaset driver prevents it from trying to send the +++ break sequence if the device has been disconnected, and removes a couple of assignments which didn't have any effect. Signed-off-by:
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Tilman Schmidt authored
The following patch to the Siemens Gigaset base driver adds graceful recovery for some frequently encountered error conditions, by retrying failed control requests (eg. stalled control pipe), and by closing and reopening the AT command channel when it appears to be stuck. Signed-off-by:
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Eric Sesterhenn authored
This fixes coverity bug #517. Since IESIZE is greater than IESIZE_NI1 we might run past the end of ielist_ni1. This fixes it by using the proper IESIZE_NI1 define. Signed-off-by:
Eric Sesterhenn <snakebyte@gmx.de> Acked-by:
Karsten Keil <kkeil@suse.de> Signed-off-by:
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Michael Buesch authored
I am getting more or less reproducible crashes from the CAPI subsystem using the fcdsl driver: Unable to handle kernel NULL pointer dereference at virtual address 00000010 printing eip: c39bbca4 *pde = 00000000 Oops: 0000 [#1] Modules linked in: netconsole capi capifs 3c59x mii fcdsl kernelcapi uhci_hcd usbcore ide_cd cdrom CPU: 0 EIP: 0060:[<c39bbca4>] Tainted: P VLI EFLAGS: 00010202 (2.6.16.11 #3) EIP is at handle_minor_send+0x17a/0x241 [capi] eax: c24abbc0 ebx: c0b4c980 ecx: 00000010 edx: 00000010 esi: c1679140 edi: c2783016 ebp: 0000c28d esp: c0327e24 ds: 007b es: 007b ss: 0068 Process swapper (pid: 0, threadinfo=c0326000 task=c02e1300) Stack: <0>000005b4 c1679180 00000000 c28d0000 c1ce04e0 c2f69654 c221604e c1679140 c39bc19a 00000038 c20c0400 c075c560 c1f2f800 00000000 c01dc9b5 c1e96a40 c075c560 c2ed64c0 c1e96a40 c01dcd3b c2fb94e8 c075c560 c0327f00 c1e96a40 Call Trace: [<c39bc19a>] capinc_tty_write+0xda/0xf3 [capi] [<c01dc9b5>] ppp_sync_push+0x52/0xfe [<c01dcd3b>] ppp_sync_send+0x1f5/0x204 [<c01d9bc1>] ppp_push+0x3e/0x9c [<c01dacd4>] ppp_xmit_process+0x422/0x4cc [<c01daf3f>] ppp_start_xmit+0x1c1/0x1f6 [<c0213ea5>] qdisc_restart+0xa7/0x135 [<c020b112>] dev_queue_xmit+0xba/0x19e [<c0223f69>] ip_output+0x1eb/0x236 [<c0220907>] ip_forward+0x1c1/0x21a [<c021fa6c>] ip_rcv+0x38e/0x3ea [<c020b4c2>] netif_receive_skb+0x166/0x195 [<c020b55e>] process_backlog+0x6d/0xd2 [<c020a30f>] net_rx_action+0x6a/0xff [<c0112909>] __do_softirq+0x35/0x7d [<c0112973>] do_softirq+0x22/0x26 [<c0103a9d>] do_IRQ+0x1e/0x25 [<c010255a>] common_interrupt+0x1a/0x20 [<c01013c5>] default_idle+0x2b/0x53 [<c0101426>] cpu_idle+0x39/0x4e [<c0328386>] start_kernel+0x20b/0x20d Code: c0 e8 b3 b6 77 fc 85 c0 75 10 68 d8 c8 9b c3 e8 82 3d 75 fc 8b 43 60 5a eb 50 8d 56 50 c7 00 00 00 00 00 66 89 68 04 eb 02 89 ca <8b> 0a 85 c9 75 f8 89 02 89 da ff 46 54 8b 46 10 e8 30 79 fd ff <0>Kernel panic - not syncing: Fatal exception in interrupt That oops took me to the "ackqueue" implementation in capi.c. The crash occured in capincci_add_ack() (auto-inlined by the compiler). I read the code a bit and finally decided to replace the custom linked list implementation (struct capiminor->ackqueue) by a struct list_head. That did not solve the crash, but produced the following interresting oops: Unable to handle kernel paging request at virtual address 00200200 printing eip: c39bb1f5 *pde = 00000000 Oops: 0002 [#1] Modules linked in: netconsole capi capifs 3c59x mii fcdsl kernelcapi uhci_hcd usbcore ide_cd cdrom CPU: 0 EIP: 0060:[<c39bb1f5>] Tainted: P VLI EFLAGS: 00010246 (2.6.16.11 #3) EIP is at capiminor_del_ack+0x18/0x49 [capi] eax: 00200200 ebx: c18d41a0 ecx: c1385620 edx: 00100100 esi: 0000d147 edi: 00001103 ebp: 0000d147 esp: c1093f3c ds: 007b es: 007b ss: 0068 Process events/0 (pid: 3, threadinfo=c1092000 task=c1089030) Stack: <0>c2a17580 c18d41a0 c39bbd16 00000038 c18d41e0 00000000 d147c640 c29e0b68 c29e0b90 00000212 c29e0b68 c39932b2 c29e0bb0 c10736a0 c0119ef0 c399326c c10736a8 c10736a0 c10736b0 c0119f93 c011a06e 00000001 00000000 00000000 Call Trace: [<c39bbd16>] handle_minor_send+0x1af/0x241 [capi] [<c39932b2>] recv_handler+0x46/0x5f [kernelcapi] [<c0119ef0>] run_workqueue+0x5e/0x8d [<c399326c>] recv_handler+0x0/0x5f [kernelcapi] [<c0119f93>] worker_thread+0x0/0x10b [<c011a06e>] worker_thread+0xdb/0x10b [<c010c998>] default_wake_function+0x0/0xc [<c011c399>] kthread+0x90/0xbc [<c011c309>] kthread+0x0/0xbc [<c0100a65>] kernel_thread_helper+0x5/0xb Code: 7e 02 89 ee 89 f0 5a f7 d0 c1 f8 1f 5b 21 f0 5e 5f 5d c3 56 53 8b 48 50 89 d6 89 c3 8b 11 eb 2f 66 39 71 08 75 25 8b 41 04 8b 11 <89> 10 89 42 04 c7 01 00 01 10 00 89 c8 c7 41 04 00 02 20 00 e8 The interresting part of it is the "virtual address 00200200", which is LIST_POISON2. I thought about some race condition, but as this is an UP system, it leads to questions on how it can happen. If we look at EFLAGS: 00010202, we see that interrupts are enabled at the time of the crash (eflags & 0x200). Finally, I don't understand all the capi code, but I think that handle_minor_send() is racing somehow against capi_recv_message(), which call both capiminor_del_ack(). So if an IRQ occurs in the middle of capiminor_del_ack() and another instance of it is invoked, it leads to linked list corruption. I came up with the following patch. With this, I could not reproduce the crash anymore. Clearly, this is not the correct fix for the issue. As this seems to be some locking issue, there might be more locking issues in that code. For example, doesn't the whole struct capiminor have to be locked somehow? Cc: Carsten Paeth <calle@calle.de> Cc: Kai Germaschewski <kai.germaschewski@gmx.de> Cc: Karsten Keil <kkeil@suse.de> Signed-off-by: -
Anil S Keshavamurthy authored
With this patch Kprobes now registers for page fault notifications only when their is an active probe registered. Once all the active probes are unregistered their is no need to be notified of page faults and kprobes unregisters itself from the page fault notifications. Hence we will have ZERO side effects when no probes are active. Signed-off-by:
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by:
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Anil S Keshavamurthy authored
Kprobes now registers for page fault notifications. Signed-off-by:
Anil S Keshavamurthy <anil.s.keshavmurthy@intel.com> Signed-off-by:
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Anil S Keshavamurthy authored
Overloading of page fault notification with the notify_die() has performance issues(since the only interested components for page fault is kprobes and/or kdb) and hence this patch introduces the new notifier call chain exclusively for page fault notifications their by avoiding notifying unnecessary components in the do_page_fault() code path. Signed-off-by:
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Anil S Keshavamurthy authored
Overloading of page fault notification with the notify_die() has performance issues(since the only interested components for page fault is kprobes and/or kdb) and hence this patch introduces the new notifier call chain exclusively for page fault notifications their by avoiding notifying unnecessary components in the do_page_fault() code path. Signed-off-by:
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Anil S Keshavamurthy authored
Overloading of page fault notification with the notify_die() has performance issues(since the only interested components for page fault is kprobes and/or kdb) and hence this patch introduces the new notifier call chain exclusively for page fault notifications their by avoiding notifying unnecessary components in the do_page_fault() code path. Signed-off-by:
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Anil S Keshavamurthy authored
Overloading of page fault notification with the notify_die() has performance issues(since the only interested components for page fault is kprobes and/or kdb) and hence this patch introduces the new notifier call chain exclusively for page fault notifications their by avoiding notifying unnecessary components in the do_page_fault() code path. Signed-off-by:
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Anil S Keshavamurthy authored
Currently in the do_page_fault() code path, we call notify_die(DIE_PAGE_FAULT, ...) to notify the page fault. Since notify_die() is highly overloaded, this page fault notification is currently being sent to all the components registered with register_die_notification() which uses the same die_chain to loop for all the registered components which is unnecessary. In order to optimize the do_page_fault() code path, this critical page fault notification is now moved to different call chain and the test results showed great improvements. And the kprobes which is interested in this notifications, now registers onto this new call chain only when it need to, i.e Kprobes now registers for page fault notification only when their are an active probes and unregisters from this page fault notification when no probes are active. I have incorporated all the feedback given by Ananth and Keith and everyone, and thanks for all the review feedback. This patch: Overloading of page fault notification with the notify_die() has performance issues(since the only interested components for page fault is kprobes and/or kdb) and hence this patch introduces the new notifier call chain exclusively for page fault notifications their by avoiding notifying unnecessary components in the do_page_fault() code path. Signed-off-by:
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mao, bibo authored
If there are multi kprobes on the same probepoint, there will be one extra aggr_kprobe on the head of kprobe list. The aggr_kprobe has aggr_post_handler/aggr_break_handler whether the other kprobe post_hander/break_handler is NULL or not. This patch modifies this, only when there is one or more kprobe in the list whose post_handler is not NULL, post_handler of aggr_kprobe will be set as aggr_post_handler. [soshima@redhat.com: !CONFIG_PREEMPT fix] Signed-off-by:
bibo, mao <bibo.mao@intel.com> Cc: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com> Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Yumiko Sugita <sugita@sdl.hitachi.co.jp> Cc: Hideo Aoki <haoki@redhat.com> Signed-off-by:
Satoshi Oshima <soshima@redhat.com> Signed-off-by:
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Masami Hiramatsu authored
Previous kprobe-booster patch has not handled any 2byte opcodes and prefixes. I checked whole IA32 opcode map and classified it. This patch enables kprobe to boost those 2byte opcodes and prefixes. Signed-off-by:
Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com> Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Yumiko Sugita <sugita@sdl.hitachi.co.jp> Cc: Satoshi Oshima <soshima@redhat.com> Cc: Hideo Aoki <haoki@redhat.com> Signed-off-by:
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Jim Cromie authored
Add a GTOD clocksource driver based on the Geode SCx200's Hi-Res Timer. Signed-off-by:
Jim Cromie <jim.cromie@gmail.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by:
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