linux.git/arch/parisc, branch v3.18.72 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git parisc/mm: Ensure IRQs are off in switch_mm() 2017-07-21T06:12:22+00:00 Helge Deller deller@gmx.de 2017-05-29T15:14:16+00:00 de7a2dcb0e3ae398e9689859e40662dcd6724040 commit 649aa24254e85bf6bd7807dd372d083707852b1f upstream. This is because of commit f98db6013c55 ("sched/core: Add switch_mm_irqs_off() and use it in the scheduler") in which switch_mm_irqs_off() is called by the scheduler, vs switch_mm() which is used by use_mm(). This patch lets the parisc code mirror the x86 and powerpc code, ie. it disables interrupts in switch_mm(), and optimises the scheduler case by defining switch_mm_irqs_off(). Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 649aa24254e85bf6bd7807dd372d083707852b1f upstream.

This is because of commit f98db6013c55 ("sched/core: Add switch_mm_irqs_off()
and use it in the scheduler") in which switch_mm_irqs_off() is called by the
scheduler, vs switch_mm() which is used by use_mm().

This patch lets the parisc code mirror the x86 and powerpc code, ie. it
disables interrupts in switch_mm(), and optimises the scheduler case by
defining switch_mm_irqs_off().

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parisc: DMA API: return error instead of BUG_ON for dma ops on non dma devs 2017-07-21T06:12:22+00:00 Thomas Bogendoerfer tsbogend@alpha.franken.de 2017-07-03T08:38:05+00:00 c6006ec76a7c741ce91f59cc06ed07ecf618daef commit 33f9e02495d15a061f0c94ef46f5103a2d0c20f3 upstream. Enabling parport pc driver on a B2600 (and probably other 64bit PARISC systems) produced following BUG: CPU: 0 PID: 1 Comm: swapper Not tainted 4.12.0-rc5-30198-g1132d5e #156 task: 000000009e050000 task.stack: 000000009e04c000 YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI PSW: 00001000000001101111111100001111 Not tainted r00-03 000000ff0806ff0f 000000009e04c990 0000000040871b78 000000009e04cac0 r04-07 0000000040c14de0 ffffffffffffffff 000000009e07f098 000000009d82d200 r08-11 000000009d82d210 0000000000000378 0000000000000000 0000000040c345e0 r12-15 0000000000000005 0000000040c345e0 0000000000000000 0000000040c9d5e0 r16-19 0000000040c345e0 00000000f00001c4 00000000f00001bc 0000000000000061 r20-23 000000009e04ce28 0000000000000010 0000000000000010 0000000040b89e40 r24-27 0000000000000003 0000000000ffffff 000000009d82d210 0000000040c14de0 r28-31 0000000000000000 000000009e04ca90 000000009e04cb40 0000000000000000 sr00-03 0000000000000000 0000000000000000 0000000000000000 0000000000000000 sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000 IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000404aece0 00000000404aece4 IIR: 03ffe01f ISR: 0000000010340000 IOR: 000001781304cac8 CPU: 0 CR30: 000000009e04c000 CR31: 00000000e2976de2 ORIG_R28: 0000000000000200 IAOQ[0]: sba_dma_supported+0x80/0xd0 IAOQ[1]: sba_dma_supported+0x84/0xd0 RP(r2): parport_pc_probe_port+0x178/0x1200 Cause is a call to dma_coerce_mask_and_coherenet in parport_pc_probe_port, which PARISC DMA API doesn't handle very nicely. This commit gives back DMA_ERROR_CODE for DMA API calls, if device isn't capable of DMA transaction. Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 33f9e02495d15a061f0c94ef46f5103a2d0c20f3 upstream.

Enabling parport pc driver on a B2600 (and probably other 64bit PARISC
systems) produced following BUG:

CPU: 0 PID: 1 Comm: swapper Not tainted 4.12.0-rc5-30198-g1132d5e #156
task: 000000009e050000 task.stack: 000000009e04c000

     YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
PSW: 00001000000001101111111100001111 Not tainted
r00-03  000000ff0806ff0f 000000009e04c990 0000000040871b78 000000009e04cac0
r04-07  0000000040c14de0 ffffffffffffffff 000000009e07f098 000000009d82d200
r08-11  000000009d82d210 0000000000000378 0000000000000000 0000000040c345e0
r12-15  0000000000000005 0000000040c345e0 0000000000000000 0000000040c9d5e0
r16-19  0000000040c345e0 00000000f00001c4 00000000f00001bc 0000000000000061
r20-23  000000009e04ce28 0000000000000010 0000000000000010 0000000040b89e40
r24-27  0000000000000003 0000000000ffffff 000000009d82d210 0000000040c14de0
r28-31  0000000000000000 000000009e04ca90 000000009e04cb40 0000000000000000
sr00-03  0000000000000000 0000000000000000 0000000000000000 0000000000000000
sr04-07  0000000000000000 0000000000000000 0000000000000000 0000000000000000

IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000404aece0 00000000404aece4
 IIR: 03ffe01f    ISR: 0000000010340000  IOR: 000001781304cac8
 CPU:        0   CR30: 000000009e04c000 CR31: 00000000e2976de2
 ORIG_R28: 0000000000000200
 IAOQ[0]: sba_dma_supported+0x80/0xd0
 IAOQ[1]: sba_dma_supported+0x84/0xd0
 RP(r2): parport_pc_probe_port+0x178/0x1200

Cause is a call to dma_coerce_mask_and_coherenet in parport_pc_probe_port,
which PARISC DMA API doesn't handle very nicely. This commit gives back
DMA_ERROR_CODE for DMA API calls, if device isn't capable of DMA
transaction.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parisc: use compat_sys_keyctl() 2017-07-21T06:12:22+00:00 Eric Biggers ebiggers@google.com 2017-06-13T06:18:30+00:00 2566eeeda9891bfc3585826e5b68629a704c64da commit b0f94efd5aa8daa8a07d7601714c2573266cd4c9 upstream. Architectures with a compat syscall table must put compat_sys_keyctl() in it, not sys_keyctl(). The parisc architecture was not doing this; fix it. Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Helge Deller <deller@gmx.de> Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b0f94efd5aa8daa8a07d7601714c2573266cd4c9 upstream.

Architectures with a compat syscall table must put compat_sys_keyctl()
in it, not sys_keyctl().  The parisc architecture was not doing this;
fix it.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parisc: Report SIGSEGV instead of SIGBUS when running out of stack 2017-07-21T06:12:22+00:00 Helge Deller deller@gmx.de 2017-07-02T20:00:41+00:00 cd01854e969acfb1671bff680fa169a850c10845 commit 247462316f85a9e0479445c1a4223950b68ffac1 upstream. When a process runs out of stack the parisc kernel wrongly faults with SIGBUS instead of the expected SIGSEGV signal. This example shows how the kernel faults: do_page_fault() command='a.out' type=15 address=0xfaac2000 in libc-2.24.so[f8308000+16c000] trap #15: Data TLB miss fault, vm_start = 0xfa2c2000, vm_end = 0xfaac2000 The vma->vm_end value is the first address which does not belong to the vma, so adjust the check to include vma->vm_end to the range for which to send the SIGSEGV signal. This patch unbreaks building the debian libsigsegv package. Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 247462316f85a9e0479445c1a4223950b68ffac1 upstream.

When a process runs out of stack the parisc kernel wrongly faults with SIGBUS
instead of the expected SIGSEGV signal.

This example shows how the kernel faults:
do_page_fault() command='a.out' type=15 address=0xfaac2000 in libc-2.24.so[f8308000+16c000]
trap #15: Data TLB miss fault, vm_start = 0xfa2c2000, vm_end = 0xfaac2000

The vma->vm_end value is the first address which does not belong to the vma, so
adjust the check to include vma->vm_end to the range for which to send the
SIGSEGV signal.

This patch unbreaks building the debian libsigsegv package.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm: larger stack guard gap, between vmas 2017-06-26T05:10:54+00:00 Hugh Dickins hughd@google.com 2017-06-19T11:03:24+00:00 d4712eb79b17d85c9e354efa2d3156ce50736128 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 <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [wt: backport to 4.11: adjust context] [wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide] [wt: backport to 4.4: adjust context ; drop ppc hugetlb_radix changes] [wt: backport to 3.18: adjust context ; no FOLL_POPULATE ; s390 uses generic arch_get_unmapped_area()] Signed-off-by: Willy Tarreau <w@1wt.eu> [gkh: minor build fixes for 3.18] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
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 <oleg@redhat.com>
Original-patch-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[wt: backport to 4.11: adjust context]
[wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide]
[wt: backport to 4.4: adjust context ; drop ppc hugetlb_radix changes]
[wt: backport to 3.18: adjust context ; no FOLL_POPULATE ;
     s390 uses generic arch_get_unmapped_area()]
Signed-off-by: Willy Tarreau <w@1wt.eu>
[gkh: minor build fixes for 3.18]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parisc: Ensure consistent state when switching to kernel stack at syscall entry 2016-11-24T04:09:24+00:00 John David Anglin dave.anglin@bell.net 2016-10-29T03:00:34+00:00 056bcad97c8e1ac7f6287a45b090ea51f93565cf [ Upstream commit 6ed518328d0189e0fdf1bb7c73290d546143ea66 ] We have one critical section in the syscall entry path in which we switch from the userspace stack to kernel stack. In the event of an external interrupt, the interrupt code distinguishes between those two states by analyzing the value of sr7. If sr7 is zero, it uses the kernel stack. Therefore it's important, that the value of sr7 is in sync with the currently enabled stack. This patch now disables interrupts while executing the critical section. This prevents the interrupt handler to possibly see an inconsistent state which in the worst case can lead to crashes. Interestingly, in the syscall exit path interrupts were already disabled in the critical section which switches back to the userspace stack. Cc: <stable@vger.kernel.org> Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> 
[ Upstream commit 6ed518328d0189e0fdf1bb7c73290d546143ea66 ]

We have one critical section in the syscall entry path in which we switch from
the userspace stack to kernel stack. In the event of an external interrupt, the
interrupt code distinguishes between those two states by analyzing the value of
sr7. If sr7 is zero, it uses the kernel stack. Therefore it's important, that
the value of sr7 is in sync with the currently enabled stack.

This patch now disables interrupts while executing the critical section.  This
prevents the interrupt handler to possibly see an inconsistent state which in
the worst case can lead to crashes.

Interestingly, in the syscall exit path interrupts were already disabled in the
critical section which switches back to the userspace stack.

Cc: <stable@vger.kernel.org>
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
parisc: fix copy_from_user() 2016-10-06T02:40:20+00:00 Al Viro viro@zeniv.linux.org.uk 2016-08-20T23:03:37+00:00 6c696327470978196e46cc588debdbc90164a198 [ Upstream commit aace880feea38875fbc919761b77e5732a3659ef ] Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> 
[ Upstream commit aace880feea38875fbc919761b77e5732a3659ef ]

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
parisc: Fix order of EREFUSED define in errno.h 2016-09-01T02:05:44+00:00 Helge Deller deller@gmx.de 2016-08-20T09:51:38+00:00 a0d020d209d4307c113bc2bcfc3302ce29b66eaf [ Upstream commit 3eb53b20d7bd1374598cfb1feaa081fcac0e76cd ] When building gccgo in userspace, errno.h gets parsed and the go include file sysinfo.go is generated. Since EREFUSED is defined to the same value as ECONNREFUSED, and ECONNREFUSED is defined later on in errno.h, this leads to go complaining that EREFUSED isn't defined yet. Fix this trivial problem by moving the define of EREFUSED down after ECONNREFUSED in errno.h (and clean up the indenting while touching this line). Signed-off-by: Helge Deller <deller@gmx.de> Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <alexander.levin@verizon.com> 
[ Upstream commit 3eb53b20d7bd1374598cfb1feaa081fcac0e76cd ]

When building gccgo in userspace, errno.h gets parsed and the go include file
sysinfo.go is generated.

Since EREFUSED is defined to the same value as ECONNREFUSED, and ECONNREFUSED
is defined later on in errno.h, this leads to go complaining that EREFUSED
isn't defined yet.

Fix this trivial problem by moving the define of EREFUSED down after
ECONNREFUSED in errno.h (and clean up the indenting while touching this line).

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
parisc: Fix pagefault crash in unaligned __get_user() call 2016-06-20T03:47:44+00:00 Helge Deller deller@gmx.de 2016-06-04T15:21:33+00:00 ec5ef4f89be8c7b14deb23a684b6adc3e4c3c220 [ Upstream commit 8b78f260887df532da529f225c49195d18fef36b ] One of the debian buildd servers had this crash in the syslog without any other information: Unaligned handler failed, ret = -2 clock_adjtime (pid 22578): Unaligned data reference (code 28) CPU: 1 PID: 22578 Comm: clock_adjtime Tainted: G E 4.5.0-2-parisc64-smp #1 Debian 4.5.4-1 task: 000000007d9960f8 ti: 00000001bde7c000 task.ti: 00000001bde7c000 YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI PSW: 00001000000001001111100000001111 Tainted: G E r00-03 000000ff0804f80f 00000001bde7c2b0 00000000402d2be8 00000001bde7c2b0 r04-07 00000000409e1fd0 00000000fa6f7fff 00000001bde7c148 00000000fa6f7fff r08-11 0000000000000000 00000000ffffffff 00000000fac9bb7b 000000000002b4d4 r12-15 000000000015241c 000000000015242c 000000000000002d 00000000fac9bb7b r16-19 0000000000028800 0000000000000001 0000000000000070 00000001bde7c218 r20-23 0000000000000000 00000001bde7c210 0000000000000002 0000000000000000 r24-27 0000000000000000 0000000000000000 00000001bde7c148 00000000409e1fd0 r28-31 0000000000000001 00000001bde7c320 00000001bde7c350 00000001bde7c218 sr00-03 0000000001200000 0000000001200000 0000000000000000 0000000001200000 sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000 IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000402d2e84 00000000402d2e88 IIR: 0ca0d089 ISR: 0000000001200000 IOR: 00000000fa6f7fff CPU: 1 CR30: 00000001bde7c000 CR31: ffffffffffffffff ORIG_R28: 00000002369fe628 IAOQ[0]: compat_get_timex+0x2dc/0x3c0 IAOQ[1]: compat_get_timex+0x2e0/0x3c0 RP(r2): compat_get_timex+0x40/0x3c0 Backtrace: [<00000000402d4608>] compat_SyS_clock_adjtime+0x40/0xc0 [<0000000040205024>] syscall_exit+0x0/0x14 This means the userspace program clock_adjtime called the clock_adjtime() syscall and then crashed inside the compat_get_timex() function. Syscalls should never crash programs, but instead return EFAULT. The IIR register contains the executed instruction, which disassebles into "ldw 0(sr3,r5),r9". This load-word instruction is part of __get_user() which tried to read the word at %r5/IOR (0xfa6f7fff). This means the unaligned handler jumped in. The unaligned handler is able to emulate all ldw instructions, but it fails if it fails to read the source e.g. because of page fault. The following program reproduces the problem: #define _GNU_SOURCE #include <unistd.h> #include <sys/syscall.h> #include <sys/mman.h> int main(void) { /* allocate 8k */ char *ptr = mmap(NULL, 2*4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); /* free second half (upper 4k) and make it invalid. */ munmap(ptr+4096, 4096); /* syscall where first int is unaligned and clobbers into invalid memory region */ /* syscall should return EFAULT */ return syscall(__NR_clock_adjtime, 0, ptr+4095); } To fix this issue we simply need to check if the faulting instruction address is in the exception fixup table when the unaligned handler failed. If it is, call the fixup routine instead of crashing. While looking at the unaligned handler I found another issue as well: The target register should not be modified if the handler was unsuccessful. Signed-off-by: Helge Deller <deller@gmx.de> Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <sasha.levin@oracle.com> 
[ Upstream commit 8b78f260887df532da529f225c49195d18fef36b ]

One of the debian buildd servers had this crash in the syslog without
any other information:

 Unaligned handler failed, ret = -2
 clock_adjtime (pid 22578): Unaligned data reference (code 28)
 CPU: 1 PID: 22578 Comm: clock_adjtime Tainted: G  E  4.5.0-2-parisc64-smp #1 Debian 4.5.4-1
 task: 000000007d9960f8 ti: 00000001bde7c000 task.ti: 00000001bde7c000

      YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
 PSW: 00001000000001001111100000001111 Tainted: G            E
 r00-03  000000ff0804f80f 00000001bde7c2b0 00000000402d2be8 00000001bde7c2b0
 r04-07  00000000409e1fd0 00000000fa6f7fff 00000001bde7c148 00000000fa6f7fff
 r08-11  0000000000000000 00000000ffffffff 00000000fac9bb7b 000000000002b4d4
 r12-15  000000000015241c 000000000015242c 000000000000002d 00000000fac9bb7b
 r16-19  0000000000028800 0000000000000001 0000000000000070 00000001bde7c218
 r20-23  0000000000000000 00000001bde7c210 0000000000000002 0000000000000000
 r24-27  0000000000000000 0000000000000000 00000001bde7c148 00000000409e1fd0
 r28-31  0000000000000001 00000001bde7c320 00000001bde7c350 00000001bde7c218
 sr00-03  0000000001200000 0000000001200000 0000000000000000 0000000001200000
 sr04-07  0000000000000000 0000000000000000 0000000000000000 0000000000000000

 IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000402d2e84 00000000402d2e88
  IIR: 0ca0d089    ISR: 0000000001200000  IOR: 00000000fa6f7fff
  CPU:        1   CR30: 00000001bde7c000 CR31: ffffffffffffffff
  ORIG_R28: 00000002369fe628
  IAOQ[0]: compat_get_timex+0x2dc/0x3c0
  IAOQ[1]: compat_get_timex+0x2e0/0x3c0
  RP(r2): compat_get_timex+0x40/0x3c0
 Backtrace:
  [<00000000402d4608>] compat_SyS_clock_adjtime+0x40/0xc0
  [<0000000040205024>] syscall_exit+0x0/0x14

This means the userspace program clock_adjtime called the clock_adjtime()
syscall and then crashed inside the compat_get_timex() function.
Syscalls should never crash programs, but instead return EFAULT.

The IIR register contains the executed instruction, which disassebles
into "ldw 0(sr3,r5),r9".
This load-word instruction is part of __get_user() which tried to read the word
at %r5/IOR (0xfa6f7fff). This means the unaligned handler jumped in.  The
unaligned handler is able to emulate all ldw instructions, but it fails if it
fails to read the source e.g. because of page fault.

The following program reproduces the problem:

#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/mman.h>

int main(void) {
        /* allocate 8k */
        char *ptr = mmap(NULL, 2*4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
        /* free second half (upper 4k) and make it invalid. */
        munmap(ptr+4096, 4096);
        /* syscall where first int is unaligned and clobbers into invalid memory region */
        /* syscall should return EFAULT */
        return syscall(__NR_clock_adjtime, 0, ptr+4095);
}

To fix this issue we simply need to check if the faulting instruction address
is in the exception fixup table when the unaligned handler failed. If it
is, call the fixup routine instead of crashing.

While looking at the unaligned handler I found another issue as well: The
target register should not be modified if the handler was unsuccessful.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
parisc: fix a bug when syscall number of tracee is __NR_Linux_syscalls 2016-05-18T01:48:06+00:00 Dmitry V. Levin ldv@altlinux.org 2016-04-27T01:56:11+00:00 aa7ebd32f9cbc09ccb469701fd58f877dac349ad [ Upstream commit f0b22d1bb2a37a665a969e95785c75a4f49d1499 ] Do not load one entry beyond the end of the syscall table when the syscall number of a traced process equals to __NR_Linux_syscalls. Similar bug with regular processes was fixed by commit 3bb457af4fa8 ("[PARISC] Fix bug when syscall nr is __NR_Linux_syscalls"). This bug was found by strace test suite. Cc: stable@vger.kernel.org Signed-off-by: Dmitry V. Levin <ldv@altlinux.org> Acked-by: Helge Deller <deller@gmx.de> Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> 
[ Upstream commit f0b22d1bb2a37a665a969e95785c75a4f49d1499 ]

Do not load one entry beyond the end of the syscall table when the
syscall number of a traced process equals to __NR_Linux_syscalls.
Similar bug with regular processes was fixed by commit 3bb457af4fa8
("[PARISC] Fix bug when syscall nr is __NR_Linux_syscalls").

This bug was found by strace test suite.

Cc: stable@vger.kernel.org
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>