There is a potential out-of-bounds access when using test_bit() on a
single word. The test_bit() and set_bit() functions operate on long
values, and when testing or setting a single word, they can exceed the
word boundary. KASAN detects this issue and produces a dump:
BUG: KASAN: slab-out-of-bounds in _scsih_add_device.constprop.0 (./arch/x86/include/asm/bitops.h:60 ./include/asm-generic/bitops/instrumented-atomic.h:29 drivers/scsi/mpt3sas/mpt3sas_scsih.c:7331) mpt3sas
Write of size 8 at addr ffff8881d26e3c60 by task kworker/u1536:2/2965
For full log, please look at [1].
Make the allocation at least the size of sizeof(unsigned long) so that
set_bit() and test_bit() have sufficient room for read/write operations
without overwriting unallocated memory.
[1] Link: https://lore.kernel.org/all/[email protected]/
Suggested-by: Keith Busch <[email protected]>
Signed-off-by: Breno Leitao <[email protected]>
---
drivers/scsi/mpt3sas/mpt3sas_base.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index 258647fc6bdd..fe9f4a4175d1 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -8512,6 +8512,12 @@ mpt3sas_base_attach(struct MPT3SAS_ADAPTER *ioc)
ioc->pd_handles_sz = (ioc->facts.MaxDevHandle / 8);
if (ioc->facts.MaxDevHandle % 8)
ioc->pd_handles_sz++;
+ /* pd_handles_sz should have, at least, the minimal room
+ * for set_bit()/test_bit(), otherwise out-of-memory touch
+ * may occur
+ */
+ ioc->pd_handles_sz = ALIGN(ioc->pd_handles_sz, sizeof(unsigned long));
+
ioc->pd_handles = kzalloc(ioc->pd_handles_sz,
GFP_KERNEL);
if (!ioc->pd_handles) {
@@ -8529,6 +8535,12 @@ mpt3sas_base_attach(struct MPT3SAS_ADAPTER *ioc)
ioc->pend_os_device_add_sz = (ioc->facts.MaxDevHandle / 8);
if (ioc->facts.MaxDevHandle % 8)
ioc->pend_os_device_add_sz++;
+
+ /* pend_os_device_add_sz should have, at least, the minimal room
+ * for set_bit()/test_bit(), otherwise out-of-memory may occur
+ */
+ ioc->pend_os_device_add_sz = ALIGN(ioc->pend_os_device_add_sz,
+ sizeof(unsigned long));
ioc->pend_os_device_add = kzalloc(ioc->pend_os_device_add_sz,
GFP_KERNEL);
if (!ioc->pend_os_device_add) {
--
2.43.0
On Fri, May 31, 2024 at 11:00:54AM -0700, Breno Leitao wrote:
> diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
> index 258647fc6bdd..fe9f4a4175d1 100644
> --- a/drivers/scsi/mpt3sas/mpt3sas_base.c
> +++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
> @@ -8512,6 +8512,12 @@ mpt3sas_base_attach(struct MPT3SAS_ADAPTER *ioc)
> ioc->pd_handles_sz = (ioc->facts.MaxDevHandle / 8);
> if (ioc->facts.MaxDevHandle % 8)
> ioc->pd_handles_sz++;
> + /* pd_handles_sz should have, at least, the minimal room
> + * for set_bit()/test_bit(), otherwise out-of-memory touch
> + * may occur
> + */
> + ioc->pd_handles_sz = ALIGN(ioc->pd_handles_sz, sizeof(unsigned long));
> +
> ioc->pd_handles = kzalloc(ioc->pd_handles_sz,
> GFP_KERNEL);
> if (!ioc->pd_handles) {
> @@ -8529,6 +8535,12 @@ mpt3sas_base_attach(struct MPT3SAS_ADAPTER *ioc)
> ioc->pend_os_device_add_sz = (ioc->facts.MaxDevHandle / 8);
> if (ioc->facts.MaxDevHandle % 8)
> ioc->pend_os_device_add_sz++;
> +
> + /* pend_os_device_add_sz should have, at least, the minimal room
> + * for set_bit()/test_bit(), otherwise out-of-memory may occur
> + */
> + ioc->pend_os_device_add_sz = ALIGN(ioc->pend_os_device_add_sz,
> + sizeof(unsigned long));
> ioc->pend_os_device_add = kzalloc(ioc->pend_os_device_add_sz,
> GFP_KERNEL);
> if (!ioc->pend_os_device_add) {
Do we need similiar ALIGN for _base_check_ioc_facts_changes() too?
Otherwise, yeah, the {test,set,clear}_bit() ops expect an address to
something aligned to 'unsigned long'.
On Fri, May 31, 2024 at 03:10:45PM -0600, Keith Busch wrote:
> On Fri, May 31, 2024 at 11:00:54AM -0700, Breno Leitao wrote:
> > @@ -8529,6 +8535,12 @@ mpt3sas_base_attach(struct MPT3SAS_ADAPTER *ioc)
> > ioc->pend_os_device_add_sz = (ioc->facts.MaxDevHandle / 8);
> > if (ioc->facts.MaxDevHandle % 8)
> > ioc->pend_os_device_add_sz++;
> > +
> > + /* pend_os_device_add_sz should have, at least, the minimal room
> > + * for set_bit()/test_bit(), otherwise out-of-memory may occur
> > + */
> > + ioc->pend_os_device_add_sz = ALIGN(ioc->pend_os_device_add_sz,
> > + sizeof(unsigned long));
> > ioc->pend_os_device_add = kzalloc(ioc->pend_os_device_add_sz,
> > GFP_KERNEL);
> > if (!ioc->pend_os_device_add) {
> Do we need similiar ALIGN for _base_check_ioc_facts_changes() too?
Yes, that would help as well. Since it will protect
->device_remove_in_progress and others from the same problem.
Let me send a v2.
Thanks!