linux-stable.git/arch/alpha, branch v3.2.94

osf_wait4(): fix infoleak

2017-09-15T17:30:46+00:00

commit a8c39544a6eb2093c04afd5005b6192bd0e880c6 upstream.

failing sys_wait4() won't fill struct rusage...

Signed-off-by: Al Viro 
Signed-off-by: Ben Hutchings

mm: larger stack guard gap, between vmas

2017-07-02T16:12:47+00:00

commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream.

Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.

This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.

Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.

One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications.  For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).

Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.

Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.

Original-patch-by: Oleg Nesterov 
Original-patch-by: Michal Hocko 
Signed-off-by: Hugh Dickins 
Acked-by: Michal Hocko 
Tested-by: Helge Deller  # parisc
Signed-off-by: Linus Torvalds 
[Hugh Dickins: Backported to 3.2]
[bwh: Fix more instances of vma->vm_start in sparc64 impl. of
 arch_get_unmapped_area_topdown() and generic impl. of
 hugetlb_get_unmapped_area()]
Signed-off-by: Ben Hutchings

alpha: fix copy_from_user()

2016-11-20T01:01:37+00:00

commit 2561d309dfd1555e781484af757ed0115035ddb3 upstream.

it should clear the destination even when access_ok() fails.

Signed-off-by: Al Viro 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

alpha/PCI: Call iomem_is_exclusive() for IORESOURCE_MEM, but not IORESOURCE_IO

2016-08-22T21:37:08+00:00

commit c20e128030caf0537d5e906753eac1c28fefdb75 upstream.

The alpha pci_mmap_resource() is used for both IORESOURCE_MEM and
IORESOURCE_IO resources, but iomem_is_exclusive() is only applicable for
IORESOURCE_MEM.

Call iomem_is_exclusive() only for IORESOURCE_MEM resources, and do it
earlier to match the generic version of pci_mmap_resource().

Fixes: 10a0ef39fbd1 ("PCI/alpha: pci sysfs resources")
Signed-off-by: Bjorn Helgaas 
CC: Ivan Kokshaysky 
Signed-off-by: Ben Hutchings

vm: add VM_FAULT_SIGSEGV handling support

2015-02-20T00:49:40+00:00

commit 33692f27597fcab536d7cbbcc8f52905133e4aa7 upstream.

The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.

That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works.  However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.

In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV.  And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.

However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d4514 ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space.  And user space really
expected SIGSEGV, not SIGBUS.

To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it.  They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.

This is the mindless minimal patch to do this.  A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.

Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.

Reported-and-tested-by: Takashi Iwai 
Tested-by: Jan Engelhardt 
Acked-by: Heiko Carstens  # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.2:
 - Adjust filenames, context
 - Drop arc, metag, nios2 and lustre changes
 - For sh, patch both 32-bit and 64-bit implementations to use goto bad_area
 - For s390, pass int_code and trans_exc_code as arguments to do_no_context()
   and do_sigsegv()]
Signed-off-by: Ben Hutchings

alpha: add io{read,write}{16,32}be functions

2014-08-06T17:07:41+00:00

commit 25534eb7707821b796fd84f7115367e02f36aa60 upstream.

These functions are used in some PCI drivers with big-endian
MMIO space.

Admittedly it is almost certain that no one this side of the
Moon would use such a card in an Alpha but it does get us
closer to being able to build allyesconfig or allmodconfig,
and it enables the Debian default generic config to build.

Tested-by: Raúl Porcel 
Signed-off-by: Michael Cree 
Signed-off-by: Matt Turner 
Signed-off-by: Ben Hutchings

Revert "alpha: fix broken network checksum"

2014-04-30T15:23:27+00:00

This reverts commit b93b90ff7c50288d602108ae1a09673df3f799a8, which
was commit 0ef38d70d4118b2ce1a538d14357be5ff9dc2bbd upstream.
It was intended to fix a regression which never occurred in 3.2.

alpha: fix broken network checksum

2014-04-01T23:58:47+00:00

commit 0ef38d70d4118b2ce1a538d14357be5ff9dc2bbd upstream.

The patch 3ddc5b46a8e90f3c9251338b60191d0a804b0d92 breaks networking on
alpha (there is a follow-up fix 5cfe8f1ba5eebe6f4b6e5858cdb1a5be4f3272a6,
but networking is still broken even with the second patch).

The patch 3ddc5b46a8e90f3c9251338b60191d0a804b0d92 makes
csum_partial_copy_from_user check the pointer with access_ok. However,
csum_partial_copy_from_user is called also from csum_partial_copy_nocheck
and csum_partial_copy_nocheck is called on kernel pointers and it is
supposed not to check pointer validity.

This bug results in ssh session hangs if the system is loaded and bulk
data are printed to ssh terminal.

This patch fixes csum_partial_copy_nocheck to call set_fs(KERNEL_DS), so
that access_ok in csum_partial_copy_from_user accepts kernel-space
addresses.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Matt Turner 
Signed-off-by: Ben Hutchings

alpha: makefile: don't enforce small data model for kernel builds

2013-09-10T00:57:31+00:00

commit cd8d2331756751b6aeb855a3c9cb0a92fbd9c725 upstream.

Due to all of the goodness being packed into today's kernels, the
resulting image isn't as slim as it once was.

In light of this, don't pass -msmall-data to gcc, which otherwise results
in link failures due to impossible relocations when compiling anything but
the most trivial configurations.

Reviewed-by: Matt Turner 
Cc: Richard Henderson 
Cc: Ivan Kokshaysky 
Tested-by: Thorsten Kranzkowski 
Signed-off-by: Will Deacon 
Signed-off-by: Michael Cree 
Signed-off-by: Linus Torvalds 
Cc: Guenter Roeck 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Ben Hutchings

alpha: Add irongate_io to PCI bus resources

2013-04-25T19:25:33+00:00

commit aa8b4be3ac049c8b1df2a87e4d1d902ccfc1f7a9 upstream.

Fixes a NULL pointer dereference at boot on UP1500.

Reviewed-and-Tested-by: Matt Turner 
Signed-off-by: Jay Estabrook 
Signed-off-by: Matt Turner 
Signed-off-by: Michael Cree 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings