read_user_stack_slow is called with interrupts soft disabled and it copies contents
from the page which we find mapped to a specific address. To convert
userspace address to pfn, the kernel now uses lockless page table walk.
The kernel needs to make sure the pfn value read remains stable and is not released
and reused for another process while the contents are read from the page. This
can only be achieved by holding a page reference.
One of the first approaches I tried was to check the pte value after the kernel
copies the contents from the page. But as shown below we can still get it wrong
CPU0 CPU1
pte = READ_ONCE(*ptep);
pte_clear(pte);
put_page(page);
page = alloc_page();
memcpy(page_address(page), "secret password", nr);
memcpy(buf, kaddr + offset, nb);
put_page(page);
handle_mm_fault()
page = alloc_page();
set_pte(pte, page);
if (pte_val(pte) != pte_val(*ptep))
Hence switch to __get_user_pages_fast.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200505071729.54912-8-aneesh.kumar@linux.ibm.com
A lockless page table walk should be safe against parallel THP collapse, THP
split and madvise(MADV_DONTNEED)/parallel fault. This patch makes sure kernel
won't reload the pteval when checking for different conditions. The patch also added
a check for pte_present to make sure the kernel is indeed operating
on a PTE and not a pointer to level 0 table page.
The pfn value we find here can be different from the actual pfn on which
machine check happened. This can happen if we raced with a parallel update
of the page table. In such a scenario we end up isolating a wrong pfn. But that
doesn't have any other side effect.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200505071729.54912-7-aneesh.kumar@linux.ibm.com
This makes the pte_present check stricter by checking for additional _PAGE_PTE
bit. A level 1 pte pointer (THP pte) can be switched to a pointer to level 0 pte
page table page by following two operations.
1) THP split.
2) madvise(MADV_DONTNEED) in parallel to page fault.
A lockless page table walk need to make sure we can handle such changes
gracefully.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200505071729.54912-4-aneesh.kumar@linux.ibm.com
If multiple threads in userspace keep changing the protection keys
mapping a range, there can be a scenario where kernel takes a key fault
but the pkey value found in the siginfo struct is a permissive one.
This can confuse the userspace as shown in the below test case.
/* use this to control the number of test iterations */
static void pkeyreg_set(int pkey, unsigned long rights)
{
unsigned long reg, shift;
shift = (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
asm volatile("mfspr %0, 0xd" : "=r"(reg));
reg &= ~(((unsigned long) PKEY_BITS_MASK) << shift);
reg |= (rights & PKEY_BITS_MASK) << shift;
asm volatile("mtspr 0xd, %0" : : "r"(reg));
}
static unsigned long pkeyreg_get(void)
{
unsigned long reg;
asm volatile("mfspr %0, 0xd" : "=r"(reg));
return reg;
}
static int sys_pkey_mprotect(void *addr, size_t len, int prot, int pkey)
{
return syscall(SYS_pkey_mprotect, addr, len, prot, pkey);
}
static int sys_pkey_alloc(unsigned long flags, unsigned long access_rights)
{
return syscall(SYS_pkey_alloc, flags, access_rights);
}
static int sys_pkey_free(int pkey)
{
return syscall(SYS_pkey_free, pkey);
}
static int faulting_pkey;
static int permissive_pkey;
static pthread_barrier_t pkey_set_barrier;
static pthread_barrier_t mprotect_barrier;
static void pkey_handle_fault(int signum, siginfo_t *sinfo, void *ctx)
{
unsigned long pkeyreg;
/* FIXME: printf is not signal-safe but for the current purpose,
it gets the job done. */
printf("pkey: exp = %d, got = %d\n", faulting_pkey, sinfo->si_pkey);
fflush(stdout);
assert(sinfo->si_code == SEGV_PKUERR);
assert(sinfo->si_pkey == faulting_pkey);
/* clear pkey permissions to let the faulting instruction continue */
pkeyreg_set(faulting_pkey, 0x0);
}
static void *do_mprotect_fault(void *p)
{
unsigned long rights, pkeyreg, pgsize;
unsigned int i;
void *region;
int pkey;
srand(time(NULL));
pgsize = sysconf(_SC_PAGESIZE);
rights = PKEY_DISABLE_WRITE;
region = p;
/* allocate key, no permissions */
assert((pkey = sys_pkey_alloc(0, PKEY_DISABLE_ACCESS)) > 0);
pkeyreg_set(4, 0x0);
/* cache the pkey here as the faulting pkey for future reference
in the signal handler */
faulting_pkey = pkey;
printf("%s: faulting pkey = %d\n", __func__, faulting_pkey);
/* try to allocate, mprotect and free pkeys repeatedly */
for (i = 0; i < NUM_ITERATIONS; i++) {
/* sync up with the other thread here */
pthread_barrier_wait(&pkey_set_barrier);
/* make sure that the pkey used by the non-faulting thread
is made permissive for this thread's context too so that
no faults are triggered because it still might have been
set to a restrictive value */
// pkeyreg_set(permissive_pkey, 0x0);
/* sync up with the other thread here */
pthread_barrier_wait(&mprotect_barrier);
/* perform mprotect */
assert(!sys_pkey_mprotect(region, pgsize, PROT_READ | PROT_WRITE, pkey));
/* choose a random byte from the protected region and
attempt to write to it, this will generate a fault */
*((char *) region + (rand() % pgsize)) = rand();
/* restore pkey permissions as the signal handler may have
cleared the bit out for the sake of continuing */
pkeyreg_set(pkey, PKEY_DISABLE_WRITE);
}
/* free pkey */
sys_pkey_free(pkey);
return NULL;
}
static void *do_mprotect_nofault(void *p)
{
unsigned long pgsize;
unsigned int i, j;
void *region;
int pkey;
pgsize = sysconf(_SC_PAGESIZE);
region = p;
/* try to allocate, mprotect and free pkeys repeatedly */
for (i = 0; i < NUM_ITERATIONS; i++) {
/* allocate pkey, all permissions */
assert((pkey = sys_pkey_alloc(0, 0)) > 0);
permissive_pkey = pkey;
/* sync up with the other thread here */
pthread_barrier_wait(&pkey_set_barrier);
pthread_barrier_wait(&mprotect_barrier);
/* perform mprotect on the common page, no faults will
be triggered as this is most permissive */
assert(!sys_pkey_mprotect(region, pgsize, PROT_READ | PROT_WRITE, pkey));
/* free pkey */
assert(!sys_pkey_free(pkey));
}
return NULL;
}
int main(int argc, char **argv)
{
pthread_t fault_thread, nofault_thread;
unsigned long pgsize;
struct sigaction act;
pthread_attr_t attr;
cpu_set_t fault_cpuset, nofault_cpuset;
unsigned int i;
void *region;
/* allocate memory region to protect */
pgsize = sysconf(_SC_PAGESIZE);
assert(region = memalign(pgsize, pgsize));
CPU_ZERO(&fault_cpuset);
CPU_SET(0, &fault_cpuset);
CPU_ZERO(&nofault_cpuset);
CPU_SET(8, &nofault_cpuset);
assert(!pthread_attr_init(&attr));
/* setup sigsegv signal handler */
act.sa_handler = 0;
act.sa_sigaction = pkey_handle_fault;
assert(!sigprocmask(SIG_SETMASK, 0, &act.sa_mask));
act.sa_flags = SA_SIGINFO;
act.sa_restorer = 0;
assert(!sigaction(SIGSEGV, &act, NULL));
/* setup barrier for the two threads */
pthread_barrier_init(&pkey_set_barrier, NULL, 2);
pthread_barrier_init(&mprotect_barrier, NULL, 2);
/* setup and start threads */
assert(!pthread_create(&fault_thread, &attr, &do_mprotect_fault, region));
assert(!pthread_setaffinity_np(fault_thread, sizeof(cpu_set_t), &fault_cpuset));
assert(!pthread_create(&nofault_thread, &attr, &do_mprotect_nofault, region));
assert(!pthread_setaffinity_np(nofault_thread, sizeof(cpu_set_t), &nofault_cpuset));
/* cleanup */
assert(!pthread_attr_destroy(&attr));
assert(!pthread_join(fault_thread, NULL));
assert(!pthread_join(nofault_thread, NULL));
assert(!pthread_barrier_destroy(&pkey_set_barrier));
assert(!pthread_barrier_destroy(&mprotect_barrier));
free(region);
puts("PASS");
return EXIT_SUCCESS;
}
The above test can result the below failure without this patch.
pkey: exp = 3, got = 3
pkey: exp = 3, got = 4
a.out: pkey-siginfo-race.c💯 pkey_handle_fault: Assertion `sinfo->si_pkey == faulting_pkey' failed.
Aborted
Check for vma access before considering this a key fault. If vma pkey allow
access retry the acess again.
Test case is written by Sandipan Das <sandipan@linux.ibm.com> hence added SOB
from him.
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200505071729.54912-3-aneesh.kumar@linux.ibm.com
This brings in a fix from the kvm-ppc tree that was merged to mainline
after rc2, and so isn't in the base of our topic branch. We'd like it
in the topic branch because it interacts with patches we plan to carry
in this branch.
There have been cases where seemingly innocuous patches have broken the
uAPI by changing the memory layout of the parameter struct. Generally such
changes also introduce a change in the size of the entire struct. This
patch adds a sanity check to avoid such cases happening in the future.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Tested-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Move the alignment attribute of struct ipu3_uapi_awb_fr_config_s to the
field in struct ipu3_uapi_4a_config, the other location where the struct
is used.
Fixes: commit c9d52c114a ("media: staging: imgu: Address a compiler warning on alignment")
Reported-by: Tomasz Figa <tfiga@chromium.org>
Tested-by: Bingbu Cao <bingbu.cao@intel.com>
Cc: stable@vger.kernel.org # for v5.3 and up
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This reverts commit c9d52c114a.
The patch being reverted changed the memory layout of struct
ipu3_uapi_acc_param. Revert it, and address the compiler warning issues in
further patches.
Fixes: commit c9d52c114a ("media: staging: imgu: Address a compiler warning on alignment")
Reported-by: Tomasz Figa <tfiga@chromium.org>
Tested-by: Bingbu Cao <bingbu.cao@intel.com>
Cc: stable@vger.kernel.org # for v5.3 and up
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Add some explanation of the ImgU running mode and add more information
about firmware selection and running mode usage.
Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
According to the v4l spec s_fmt must return EBUSY while the
particular queue is streaming. Add such check in encoder and
decoder s_fmt methods.
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
According to stateful Codec API the decoder will process all
remaining buffers from before the source change event in
dynamic-resolution-change state and mark the last buffer with
V4L2_BUF_FLAG_LAST.
In Venus case the firmware doesn't mark that last buffer and
some mechanism have to be created in v4l decoder driver.
Fortunately the firmware interface (HFI) claims that the
decoder output buffers will be returned to v4l decoder
driver before it send the insufficient event.
In order to do that we save last queued in the driver capture
buffer in the event_notify and issue flush on output firmware
buffers queue. Once the saved buffer is returned (as a result of
flush command) we mark it as LAST. For all that possible we
extend HFI flush command with one more argument and one more
flush_done HFI driver callback.
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
According to the PMC Type C Subsystem (TCSS) Mux programming guide rev
0.6, when a device is transitioning to DP Alternate Mode state, if the
HPD_STATE (bit 7) field in the status update command VDO is set to
HPD_HIGH, the HPD_HIGH field in the Alternate Mode request “mode_data”
field (bit 14) should also be set. Ensure the bit is correctly handled
while issuing the Alternate Mode request.
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Fixes: 6701adfa96 ("usb: typec: driver for Intel PMC mux control")
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20200429054432.134178-1-pmalani@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On some architectures (e.g. arm64) requests for
IO coherent memory may use non-cachable attributes if
the relevant device isn't cache coherent. If these
pages are then remapped into userspace as cacheable,
they may not be coherent with the non-cacheable mappings.
In particular this happens with libusb, when it attempts
to create zero-copy buffers for use by rtl-sdr
(https://github.com/osmocom/rtl-sdr/). On low end arm
devices with non-coherent USB ports, the application will
be unexpectedly killed, while continuing to work fine on
arm machines with coherent USB controllers.
This bug has been discovered/reported a few times over
the last few years. In the case of rtl-sdr a compile time
option to enable/disable zero copy was implemented to
work around it.
Rather than relaying on application specific workarounds,
dma_mmap_coherent() can be used instead of remap_pfn_range().
The page cache/etc attributes will then be correctly set in
userspace to match the kernel mapping.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200504201348.1183246-1-jeremy.linton@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The syzbot fuzzer found a race between URB submission to endpoint 0
and device reset. Namely, during the reset we call usb_ep0_reinit()
because the characteristics of ep0 may have changed (if the reset
follows a firmware update, for example). While usb_ep0_reinit() is
running there is a brief period during which the pointers stored in
udev->ep_in[0] and udev->ep_out[0] are set to NULL, and if an URB is
submitted to ep0 during that period, usb_urb_ep_type_check() will
report it as a driver bug. In the absence of those pointers, the
routine thinks that the endpoint doesn't exist. The log message looks
like this:
------------[ cut here ]------------
usb 2-1: BOGUS urb xfer, pipe 2 != type 2
WARNING: CPU: 0 PID: 9241 at drivers/usb/core/urb.c:478
usb_submit_urb+0x1188/0x1460 drivers/usb/core/urb.c:478
Now, although submitting an URB while the device is being reset is a
questionable thing to do, it shouldn't count as a driver bug as severe
as submitting an URB for an endpoint that doesn't exist. Indeed,
endpoint 0 always exists, even while the device is in its unconfigured
state.
To prevent these misleading driver bug reports, this patch updates
usb_disable_endpoint() to avoid clearing the ep_in[] and ep_out[]
pointers when the endpoint being disabled is ep0. There's no danger
of leaving a stale pointer in place, because the usb_host_endpoint
structure being pointed to is stored permanently in udev->ep0; it
doesn't get deallocated until the entire usb_device structure does.
Reported-and-tested-by: syzbot+db339689b2101f6f6071@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.2005011558590.903-100000@netrider.rowland.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Presently the list initialization is done only in
dynamic-resolution-change state, which leads to list corruptions
and use-after-free. Init list_head unconditionally in
vdec_stop_capture called by vb2 stop_streaming without takeing
into account current codec state.
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Once the hfi_session_flush is issued by the vdec all queued
buffers to firmware should be returned to the v4l driver. Some
of those buffers are not processed at the time of flush command,
those buffers has filled len zero (no data). Catch that in
buffer_done callback and mark not filled capture buffers with
error state so that client can discard them.
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Currently calling venus_helper_buffers_done() will return buffers to
user for both capture and output queues in the same call. This is
wrong because both queues are really separate and calling
stop_streaming on one queue shouldn't return buffers for the other.
Solve this by add a new queue type argument and fix the clients of
the helper function.
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
The hfi_destroy function is called too early in remove method. It
destroys a mutex which is used later in the .remove from pmruntime.
Solve the issue by moving hfi_destroy after last usage of the mutex.
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
If we fails somewhere in 'v3_pci_probe()', we need to free 'host'.
Use the managed version of 'pci_alloc_host_bridge()' to do that easily.
The use of managed resources is already widely used in this driver.
Link: https://lore.kernel.org/r/20200418081637.1585-1-christophe.jaillet@wanadoo.fr
Fixes: 68a15eb7bd ("PCI: v3-semi: Add V3 Semiconductor PCI host driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
[lorenzo.pieralisi@arm.com: commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
We need a new PCode request commands and reply codes
to be added as a prepartion patch for QGV points
restricting for new SAGV support.
v2: - Extracted those changes into separate patch
(Ville Syrjälä)
v3: - Moved new PCode masks to another place from
PCode commands(Ville)
v4: - Moved new PCode masks to correspondent PCode
command, with identation(Ville)
- Changed naming to ICL_ instead of GEN11_
to fit more nicely into existing definition
style.
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200505102247.32452-5-stanislav.lisovskiy@intel.com
When a feature register field is omitted from the description of the
register, the corresponding bits are treated as STRICT RES0, including
for KVM guests. This is subtly different to declaring the field as
HIDDEN/STRICT/EXACT/0, so update the comment to call this out.
Signed-off-by: Will Deacon <will@kernel.org>
Use const for the arrays that are used as "read only". Also, modify the
prototype of vnt_control_out_blocks() function to use a pointer to a
const type.
The vnt_vt3184_al2230 array can't be converted to const as it's modified
later.
Then in the vnt_vt3184_init() function use two types of pointers (to
const type and to no const type) to avoid the compiler warning:
assignment discards 'const' qualifiers from pointer target type
This way decrease the .data section and increase the .rodata section
limiting the surface attack.
Before this change:
-------------------
drivers/staging/vt6656/baseband.o :
section size addr
.text 1278 0
.data 576 0
.bss 0 0
.rodata 319 0
.comment 45 0
.note.GNU-stack 0 0
.note.gnu.property 32 0
Total 2250
After this change:
------------------
drivers/staging/vt6656/baseband.o :
section size addr
.text 1278 0
.data 256 0
.bss 0 0
.rodata 640 0
.comment 45 0
.note.GNU-stack 0 0
.note.gnu.property 32 0
Total 2251
Signed-off-by: Oscar Carter <oscar.carter@gmx.com>
Link: https://lore.kernel.org/r/20200504171414.11307-1-oscar.carter@gmx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
