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2016-10-20x86/signal: Remove bogus user_64bit_mode() check from sigaction_compat_abi()Dmitry Safonov
The recent introduction of SA_X32/IA32 sa_flags added a check for user_64bit_mode() into sigaction_compat_abi(). user_64bit_mode() is true for native 64-bit processes and x32 processes. Due to that the function returns w/o setting the SA_X32_ABI flag for X32 processes. In consequence the kernel attempts to deliver the signal to the X32 process in native 64-bit mode causing the process to segfault. Remove the check, so the actual check for X32 mode which sets the ABI flag can be reached. There is no side effect for native 64-bit mode. [ tglx: Rewrote changelog ] Fixes: 6846351052e6 ("x86/signal: Add SA_{X32,IA32}_ABI sa_flags") Reported-by: Mikulas Patocka <mpatocka@redhat.com> Tested-by: Adam Borowski <kilobyte@angband.pl> Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: linux-mm@kvack.org Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Link: http://lkml.kernel.org/r/CAJwJo6Z8ZWPqNfT6t-i8GW1MKxQrKDUagQqnZ%2B0%2B697%3DMyVeGg@mail.gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-14x86/signal: Add SA_{X32,IA32}_ABI sa_flagsDmitry Safonov
Introduce new flags that defines which ABI to use on creating sigframe. Those flags kernel will set according to sigaction syscall ABI, which set handler for the signal being delivered. So that will drop the dependency on TIF_IA32/TIF_X32 flags on signal deliver. Those flags will be used only under CONFIG_COMPAT. Similar way ARM uses sa_flags to differ in which mode deliver signal for 26-bit applications (look at SA_THIRYTWO). Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Reviewed-by: Andy Lutomirski <luto@kernel.org> Cc: 0x7f454c46@gmail.com Cc: oleg@redhat.com Cc: linux-mm@kvack.org Cc: gorcunov@openvz.org Cc: xemul@virtuozzo.com Link: http://lkml.kernel.org/r/20160905133308.28234-7-dsafonov@virtuozzo.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-06-14x86/signals: Add build-time checks to the siginfo compat codeDave Hansen
There were at least 3 features added to the __SI_FAULT area of the siginfo struct that did not make it to the compat siginfo: 1. The si_addr_lsb used in SIGBUS's sent for machine checks 2. The upper/lower bounds for MPX SIGSEGV faults 3. The protection key for pkey faults There was also some turmoil when I was attempting to add the pkey field because it needs to be a fixed size on 32 and 64-bit and not have any alignment constraints. This patch adds some compile-time checks to the compat code to make it harder to screw this up. Basically, the checks are supposed to trip any time someone changes the siginfo structure. That sounds bad, but it's what we want. If someone changes siginfo, we want them to also be _forced_ to go look at the compat code. The details are in the comments. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-edac@vger.kernel.org Link: http://lkml.kernel.org/r/20160608172534.C73DAFC3@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-14x86/signals: Add missing signal_compat code for x86 featuresDave Hansen
The 32-bit siginfo is a different binary format than the 64-bit one. So, when running 32-bit binaries on 64-bit kernels, we have to convert the kernel's 64-bit version to a 32-bit version that userspace can grok. We've added a few features to siginfo over the past few years and neglected to add them to arch/x86/kernel/signal_compat.c: 1. The si_addr_lsb used in SIGBUS's sent for machine checks 2. The upper/lower bounds for MPX SIGSEGV faults 3. The protection key for pkey faults I caught this with some protection keys unit tests and realized it affected a few more features. This was tested only with my protection keys patch that looks for a proper value in si_pkey. I didn't actually test the machine check or MPX code. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-edac@vger.kernel.org Link: http://lkml.kernel.org/r/20160608172533.F8F05637@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-06x86/compat: Move copy_siginfo_*_user32() to signal_compat.cBrian Gerst
copy_siginfo_to_user32() and copy_siginfo_from_user32() are used by both the 32-bit compat and x32 ABIs. Move them to signal_compat.c. Signed-off-by: Brian Gerst <brgerst@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1434974121-32575-2-git-send-email-brgerst@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>