Segher Boessenkool
e4aad64597
x86/vdso: Fix building on big endian host
...
We need to call GET_LE to read hdr->e_type.
Fixes: 57f90c3dfcpaul.gortmaker@windriver.com >
Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org >
Acked-by: Andy Lutomirski <luto@kernel.org >
Cc: Stephen Rothwell <sfr@canb.auug.org.au >
Cc: linux-next@vger.kernel.org
Link: http://lkml.kernel.org/r/20160929193442.GA16617@gate.crashing.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de >
2016-09-30 12:37:40 +02:00
Andy Lutomirski
57f90c3dfc
x86/vdso: Error out if the vDSO isn't a valid DSO
...
Some distros has been playing with toolchain changes that can affect
the type of ELF objects built. Occasionally, this goes wrong and
the vDSO ends up not being a DSO at all. This causes the kernel to
end up broken in a surprisingly subtle way -- glibc apparently
silently ignores a vDSO that isn't a DSO, so everything works,
albeit slowly, until users try a different libc implementation.
Make the kernel build process a bit more robust: fail outright if
the vDSO isn't ET_DYN or is missing its PT_DYNAMIC segment. I've
never seen this in an unmodified kernel.
See: https://github.com/docker/docker/issues/23378
Signed-off-by: Andy Lutomirski <luto@kernel.org >
Cc: Borislav Petkov <bp@alien8.de >
Cc: Brian Gerst <brgerst@gmail.com >
Cc: Denys Vlasenko <dvlasenk@redhat.com >
Cc: H. Peter Anvin <hpa@zytor.com >
Cc: Josh Poimboeuf <jpoimboe@redhat.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/8a30e0a07c3b47ff917a8daa2df5e407cc0c6698.1468878336.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org >
2016-07-19 08:50:24 +02:00
Linus Torvalds
ba33ea811e
Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
...
Pull x86 asm updates from Ingo Molnar:
"This is another big update. Main changes are:
- lots of x86 system call (and other traps/exceptions) entry code
enhancements. In particular the complex parts of the 64-bit entry
code have been migrated to C code as well, and a number of dusty
corners have been refreshed. (Andy Lutomirski)
- vDSO special mapping robustification and general cleanups (Andy
Lutomirski)
- cpufeature refactoring, cleanups and speedups (Borislav Petkov)
- lots of other changes ..."
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
x86/cpufeature: Enable new AVX-512 features
x86/entry/traps: Show unhandled signal for i386 in do_trap()
x86/entry: Call enter_from_user_mode() with IRQs off
x86/entry/32: Change INT80 to be an interrupt gate
x86/entry: Improve system call entry comments
x86/entry: Remove TIF_SINGLESTEP entry work
x86/entry/32: Add and check a stack canary for the SYSENTER stack
x86/entry/32: Simplify and fix up the SYSENTER stack #DB/NMI fixup
x86/entry: Only allocate space for tss_struct::SYSENTER_stack if needed
x86/entry: Vastly simplify SYSENTER TF (single-step) handling
x86/entry/traps: Clear DR6 early in do_debug() and improve the comment
x86/entry/traps: Clear TIF_BLOCKSTEP on all debug exceptions
x86/entry/32: Restore FLAGS on SYSEXIT
x86/entry/32: Filter NT and speed up AC filtering in SYSENTER
x86/entry/compat: In SYSENTER, sink AC clearing below the existing FLAGS test
selftests/x86: In syscall_nt, test NT|TF as well
x86/asm-offsets: Remove PARAVIRT_enabled
x86/entry/32: Introduce and use X86_BUG_ESPFIX instead of paravirt_enabled
uprobes: __create_xol_area() must nullify xol_mapping.fault
x86/cpufeature: Create a new synthetic cpu capability for machine check recovery
...
2016-03-15 09:32:27 -07:00
Kees Cook
018ef8dcf3
x86/vdso: Mark the vDSO code read-only after init
...
The vDSO does not need to be writable after __init, so mark it as
__ro_after_init. The result kills the exploit method of writing to the
vDSO from kernel space resulting in userspace executing the modified code,
as shown here to bypass SMEP restrictions: http://itszn.com/blog/?p=21
The memory map (with added vDSO address reporting) shows the vDSO moving
into read-only memory:
Before:
[ 0.143067] vDSO @ ffffffff82004000
[ 0.143551] vDSO @ ffffffff82006000
---[ High Kernel Mapping ]---
0xffffffff80000000-0xffffffff81000000 16M pmd
0xffffffff81000000-0xffffffff81800000 8M ro PSE GLB x pmd
0xffffffff81800000-0xffffffff819f3000 1996K ro GLB x pte
0xffffffff819f3000-0xffffffff81a00000 52K ro NX pte
0xffffffff81a00000-0xffffffff81e00000 4M ro PSE GLB NX pmd
0xffffffff81e00000-0xffffffff81e05000 20K ro GLB NX pte
0xffffffff81e05000-0xffffffff82000000 2028K ro NX pte
0xffffffff82000000-0xffffffff8214f000 1340K RW GLB NX pte
0xffffffff8214f000-0xffffffff82281000 1224K RW NX pte
0xffffffff82281000-0xffffffff82400000 1532K RW GLB NX pte
0xffffffff82400000-0xffffffff83200000 14M RW PSE GLB NX pmd
0xffffffff83200000-0xffffffffc0000000 974M pmd
After:
[ 0.145062] vDSO @ ffffffff81da1000
[ 0.146057] vDSO @ ffffffff81da4000
---[ High Kernel Mapping ]---
0xffffffff80000000-0xffffffff81000000 16M pmd
0xffffffff81000000-0xffffffff81800000 8M ro PSE GLB x pmd
0xffffffff81800000-0xffffffff819f3000 1996K ro GLB x pte
0xffffffff819f3000-0xffffffff81a00000 52K ro NX pte
0xffffffff81a00000-0xffffffff81e00000 4M ro PSE GLB NX pmd
0xffffffff81e00000-0xffffffff81e0b000 44K ro GLB NX pte
0xffffffff81e0b000-0xffffffff82000000 2004K ro NX pte
0xffffffff82000000-0xffffffff8214c000 1328K RW GLB NX pte
0xffffffff8214c000-0xffffffff8227e000 1224K RW NX pte
0xffffffff8227e000-0xffffffff82400000 1544K RW GLB NX pte
0xffffffff82400000-0xffffffff83200000 14M RW PSE GLB NX pmd
0xffffffff83200000-0xffffffffc0000000 974M pmd
Based on work by PaX Team and Brad Spengler.
Signed-off-by: Kees Cook <keescook@chromium.org >
Acked-by: Andy Lutomirski <luto@kernel.org >
Acked-by: H. Peter Anvin <hpa@linux.intel.com >
Cc: Andy Lutomirski <luto@amacapital.net >
Cc: Arnd Bergmann <arnd@arndb.de >
Cc: Borislav Petkov <bp@alien8.de >
Cc: Brad Spengler <spender@grsecurity.net >
Cc: Brian Gerst <brgerst@gmail.com >
Cc: David Brown <david.brown@linaro.org >
Cc: Denys Vlasenko <dvlasenk@redhat.com >
Cc: Emese Revfy <re.emese@gmail.com >
Cc: H. Peter Anvin <hpa@zytor.com >
Cc: Linus Torvalds <torvalds@linux-foundation.org >
Cc: Mathias Krause <minipli@googlemail.com >
Cc: Michael Ellerman <mpe@ellerman.id.au >
Cc: PaX Team <pageexec@freemail.hu >
Cc: Peter Zijlstra <peterz@infradead.org >
Cc: Thomas Gleixner <tglx@linutronix.de >
Cc: kernel-hardening@lists.openwall.com
Cc: linux-arch <linux-arch@vger.kernel.org >
Link: http://lkml.kernel.org/r/1455748879-21872-7-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org >
2016-02-22 08:51:39 +01:00
Andy Lutomirski
05ef76b20f
x86/vdso: Use .fault for the vDSO text mapping
...
The old scheme for mapping the vDSO text is rather complicated.
vdso2c generates a struct vm_special_mapping and a blank .pages
array of the correct size for each vdso image. Init code in
vdso/vma.c populates the .pages array for each vDSO image, and
the mapping code selects the appropriate struct
vm_special_mapping.
With .fault, we can use a less roundabout approach: vdso_fault()
just returns the appropriate page for the selected vDSO image.
Signed-off-by: Andy Lutomirski <luto@kernel.org >
Reviewed-by: Kees Cook <keescook@chromium.org >
Cc: Andy Lutomirski <luto@amacapital.net >
Cc: Borislav Petkov <bp@alien8.de >
Cc: Dave Hansen <dave.hansen@linux.intel.com >
Cc: Fenghua Yu <fenghua.yu@intel.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: Quentin Casasnovas <quentin.casasnovas@oracle.com >
Cc: Thomas Gleixner <tglx@linutronix.de >
Link: http://lkml.kernel.org/r/f886954c186bafd74e1b967c8931d852ae199aa2.1451446564.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org >
2016-01-12 11:59:34 +01:00
Ingo Molnar
d603c8e184
x86/asm/entry, x86/vdso: Move the vDSO code to arch/x86/entry/vdso/
...
Cc: Borislav Petkov <bp@alien8.de >
Cc: H. Peter Anvin <hpa@zytor.com >
Cc: Linus Torvalds <torvalds@linux-foundation.org >
Cc: Thomas Gleixner <tglx@linutronix.de >
Cc: Andy Lutomirski <luto@amacapital.net >
Cc: Denys Vlasenko <dvlasenk@redhat.com >
Cc: Brian Gerst <brgerst@gmail.com >
Cc: Peter Zijlstra <peterz@infradead.org >
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org >
2015-06-03 18:51:37 +02:00
