October 2008 - Darwin-kernel

Address range returned by malloc
by Greg 04 Oct '08

04 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thanks! - Greg _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… When you call OSMalloc, IOMalloc, kern_os_malloc, or any of the other mallocs in the kernel, I'm fairly sure I've read that they all eventually call the same low-level malloc function in the kernel (vm_page_alloc() I believe). My question is what range is this address usually in? Is it reasonable to assume, given the amount of memory used by the kernel in RAM, that it will be less than the maximum value of a signed 32-bit integer, even on 64-bit systems? Or is this not a safe assumption at all? This email sent to site_archiver(a)lists.apple.com

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Re: Hard links to directories
by Michael Smith 04 Oct '08

04 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Register a task's exception port from a kext
by nicolas vide 04 Oct '08

04 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=ZNM/p/wTNuxSi7kI8JFuI3HTYK+iYRMYh1ZYOxcs1mk=; b=qnGLUzTvme6xvJ0AFK8mgpSfEtg5zwODP2SXK1g+hI0wIPR6wunh4XSLs6kHB1GAPG UDVfMAbo9qjoxiwnl6UsEOKUGtHhotMih+CYNa7ueZrbJ1cvJXPA8gz9+NrCYsdNvvMY c0TFeuBWmN1GIBxPzHKjIl8yj2FecsttcsCJQ= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=keb9U1rurvlEHqczlP2bUFxUAaoftWwZ+MBknanwmsOBRoylIUJaJCmFgqhcatv9hL 4VAltGqUd3pZV/aUyCExxf4+mIIkXmndYWmAi/rVaWkm9S5O9k1jVp+ZyKHZ5ApSKtd5 mTq8UiTHkoLZyW2A/lFCwEv7a+1p6yx+NJZZ0= On Sat, Oct 4, 2008 at 1:52 AM, Quinn <eskimo1(a)apple.com> wrote: > Specifically, if you link against the entire kernel Just to be sure, when you say link against the kernel, that means building a new kernel with my IOService built-in? I don't know if it is right but I have the feeling that Apple tries to prevent as much as possible kext's accesses to the kernel functions & data. I am neither a driver person nor a kernel programmer but I played a little with Windows and FreeBSD and I could directly access to processes data structures for example: It is ease to hide a process just by modifying kernel data from a dynamic loadable driver. Obviously, this is a big advantage to prevent anyone to play with kernel internals data, however it means that third party software like anti virus software or monitoring tools will suffer of performance and security issues, right ? > <http://www.opensource.apple.com/darwinsource/10.5/xnu-1228//bsd/uxkern/ux_e…> Thank you very much for pointing this out! Nicolas _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Register a task's exception port from a kext
by Quinn 03 Oct '08

03 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com I understand this very well but in my case it is definitely not a production software. <http://www.opensource.apple.com/darwinsource/10.5/xnu-1228//bsd/uxkern/ux_e…> [This link may require an APSL <http://www.opensource.apple.com/apsl/> account.] Good luck! -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Relations, Developer Technical Support, Core OS/Hardware _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… At 21:55 +1000 3/10/08, nicolas vide wrote: If you don't care about creating a real product, you have more options. Specifically, if you link against the entire kernel you should have access to task_set_special_port, which is a necessary first step. You will also need to use MIG (in kernel mode!) to generate a demux routine. Make sure you don't export your catch_xxx routines, lest they collide with the kernel routines of the same name. For an example of this check out the "Mach exceptions to BSD signals" code inside the kernel itself. This email sent to site_archiver(a)lists.apple.com

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Re: Hard links to directories
by Shawn Erickson 03 Oct '08

03 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=77oycGYNnxOCbA7l7dSdZV5KvotHsJiyULptvUj2fbw=; b=MrOH7AAH4KM4AKVWGD9p1lH1fQnVfTbgHZIyDDJEqZpmNDQqfxNuf/bY1ag0zww9IV nJsmxuKvBfoloECCtWxqJawJFBx3u2MjF9dUc/Fss3yRxRrsYlfKIEM/8lmo1kEicMk7 3b89vmmgM8qo4chVwmDGM8TJDhXLAmUynX0uw= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=jAH7YILVuJkDNBLYfD0ZoohT+TetTA6opmQPRIDEm3HW6sA3s1ztMTsfukXFBSkRDu PKG0FExFqiWRGEn4m4ZHJ1awrHTr0cAFEA6sv53DWbCyUDmKoNJdjf/hlnGmkFDty0Gf ZnQBtlB09wSLoBJzwsjZwgl7sKvi/FhRoKWuI= Folks it is simple... The directory hard link feature in Leopard has only been tested and qualified by Apple for the exact use case of Time Machine. TM and other system services likely have code to tap dance around potential pitfalls as long as they are used in the "sandbox" of a TM volume. Using the feature for other reasons is risky in terms of stability and availability of feature. -Shawn _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Hard links to directories
by al ameen shah 03 Oct '08

03 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type:references; bh=kRMTHISzwlx/Z3HSlnq/30FT4NmF6bb9pIHteenN1Rs=; b=jru9g/ad/8BgKjZi2ZsnhUi6ubKXio4oXuw0qc3chXn7Wci/iQgV/9q0/klTScP3dH GZUc7Wir7Rmb9GXYFEoZncC6g8n0b25mjb74ZHAR9WxgKnkCAs1BQ5VaIdwKoGJkmTS5 D3O9qUCkYkbz1VGKoRw9U8Ih2jeXPAFSt2Mbs= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:references; b=RAiub2zyQ2NU7NmiyvcIw3RVlMUNMXXjzvLeIaBW5oCWb7fNLZjqq7C7M/+jR6c8fA Y7+o5+/8OWoewnwEYhWZ+9hNTWsWiqkOR7LVXxGL5KOFXmxMjgnJBg9DjRswz/IcGvn2 j35aitvnsnuKRzF+jzPXR8G8SaRVehIynx2l4= _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Register a task's exception port from a kext
by nicolas vide 03 Oct '08

03 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=sb9xqn2diDLGy/tVjQqyA9jfvdLN8yUAVDXxGWkqVNg=; b=W32Dc7ufwYP7F8UJvCeHdCqkzozBq8wqTOsQzhdcv0qO4mxIhffnAazeudHEf8zN9+ 1vA86EDH4I+kIgXGMu6c9GzU+PTtgWuoW8jqGaCCO0LvNcL3tC40N9qV3n8/DYP3X0jh YJ8xC6eyyrBVTHWqreZiGknCdwaG7X0qSFGDk= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=SL3cL44y3uGGQpVt0faXgCDEhFXtC1sOm16h2f7LfDrj/jB9ms/w2MSDzYnwfMtdNd K6Wb8t5VxtwfWjTgdww9flotCU4qIgbY/sXgRSV/6s5fiEc2rk33Q1/mDbaPrjfengl6 A5BbGUW9myDL5cItIUp27arC7Voo1HO7+2pUs= Hi Quinn, thank you very much for your answer. On Fri, Oct 3, 2008 at 6:44 PM, Quinn <eskimo1(a)apple.com> wrote: > If you already have this running as a daemon, what's the incentive for > moving it into the kernel? In general we recommend that folks keep as much > code out of the kernel as possible, especially for things like exceptions, > which are usually not performance critical. I understand this very well but in my case it is definitely not a production software. By moving it into the kernel I just want to compare performance and security aspects between user and kernel. In a nutshell, I patch a classical mach-O in order to encrypt some code sections. I also patch the header and change the security flag of those sections to VM_PROT_NONE. That means when an encrypted page is accessed it automatically generates an exception so I can decrypt the page and fix the exception. So you think it is mission impossible to do this into the kernel ? Nicolas _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Register a task's exception port from a kext
by Quinn 03 Oct '08

03 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com I'm looking for a way to monitor exceptions raised inside a specific user task and fix them if needed. I already done this with a user daemon - using task_set_exception_ports - but this time I want to do it from the kernel side. Is it possible to "forward" an exception port to my IOUserClient ? (using IOConnectSetNotificationPort/IOUserClient::registerNotificationPort ?) Is there a way to setup an exception port directly from a IOService without using an IOUserClient ? S+E -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Relations, Developer Technical Support, Core OS/Hardware _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… At 17:47 +1000 3/10/08, nicolas vide wrote: If you already have this running as a daemon, what's the incentive for moving it into the kernel? In general we recommend that folks keep as much code out of the kernel as possible, especially for things like exceptions, which are usually not performance critical. You might be able to make some progress with this, but it really runs counter the spirit of that API. No. Firstly, the routine you need, task_set_special_port, is not part of the KPI. Secondly, that routine takes a task_t as its first parameter, and IOServices have no notion of tasks. This email sent to site_archiver(a)lists.apple.com

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Register a task's exception port from a kext
by nicolas vide 03 Oct '08

03 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:mime-version:content-type:content-transfer-encoding :content-disposition; bh=hu2/T6sbtiM/jAkmCfDeh1heecLGI1Tiyk2wYubUWQ4=; b=SI9SadrW/zM2Bkr000SwCOdYvGlthOXv4VQCe1+7Az7jDkEDWxESksxGeh3L5vp2cC 79eltrcgVajaNbZYNlfyC3eIwdS4XhHwIeD/bn/zM4yuWONGUiWkonZUAcGJJ4zjz4ti GmziWFnRXXmdINmLrYvqIRcCM0n6Wtc6hreug= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:mime-version:content-type :content-transfer-encoding:content-disposition; b=H4viCVaywYdVaEKnKt8DV4eufX55rT0VAQPH3QKnuxSEbjb6x1ekURqOxDRpYehe7E ty4HXHo83PgJldHgHo3jNGB6Dyb//Z8eN45+T2CJEDbJIuYD/fYAegBupaRdY40yzNiU NwE5zTergNQ19OsFMuxqYi9bGNr3VJosTtsFM= Hello guys, I'm looking for a way to monitor exceptions raised inside a specific user task and fix them if needed. I already done this with a user daemon - using task_set_exception_ports - but this time I want to do it from the kernel side. Is it possible to "forward" an exception port to my IOUserClient ? (using IOConnectSetNotificationPort/IOUserClient::registerNotificationPort ?) Is there a way to setup an exception port directly from a IOService without using an IOUserClient ? Thank you in advance for your answers, Nicolas _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Hard links to directories
by Mike Zuhl 03 Oct '08

03 Oct '08

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