scsi: mpt3sas: Avoid test/set_bit() operating in non-allocated memory

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.

Link: https://lore.kernel.org/all/ZkNcALr3W3KGYYJG@gmail.com/
Fixes: c696f7b83ede ("scsi: mpt3sas: Implement device_remove_in_progress check in IOCTL path")
Cc: stable@vger.kernel.org
Suggested-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20240605085530.499432-1-leitao@debian.org
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index 258647fc6bddb42b6c484bfb73055f6e40cb1c2a..1092497563b22b70797046115cb46c63ce37d05e 100644 (file)
--- 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 +8535,13 @@ 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) {
@@ -8820,6 +8833,12 @@ _base_check_ioc_facts_changes(struct MPT3SAS_ADAPTER *ioc)
                if (ioc->facts.MaxDevHandle % 8)
                        pd_handles_sz++;
 
+               /*
+                * pd_handles should have, at least, the minimal room for
+                * set_bit()/test_bit(), otherwise out-of-memory touch may
+                * occur.
+                */
+               pd_handles_sz = ALIGN(pd_handles_sz, sizeof(unsigned long));
                pd_handles = krealloc(ioc->pd_handles, pd_handles_sz,
                    GFP_KERNEL);
                if (!pd_handles) {