[PATCH AUTOSEL 5.4 15/20] usb: host: xhci: mvebu: Iterate over array indexes instead of using pointer math

[PATCH AUTOSEL 5.4 15/20] usb: host: xhci: mvebu: Iterate over array indexes instead of using pointer math

[Sasha Levin]

From: Kees Cook <keescook@chromium.org>

[ Upstream commit 0fbd2cda92cdb00f72080665554a586f88bca821 ]

Walking the dram->cs array was seen as accesses beyond the first array
item by the compiler. Instead, use the array index directly. This allows
for run-time bounds checking under CONFIG_UBSAN_BOUNDS as well. Seen
with GCC 13 with -fstrict-flex-arrays:

In function 'xhci_mvebu_mbus_config',
    inlined from 'xhci_mvebu_mbus_init_quirk' at ../drivers/usb/host/xhci-mvebu.c:66:2:
../drivers/usb/host/xhci-mvebu.c:37:28: warning: array subscript 0 is outside array bounds of 'const struct mbus_dram_window[0]' [-Warray-bounds=]
   37 |                 writel(((cs->size - 1) & 0xffff0000) | (cs->mbus_attr << 8) |
      |                          ~~^~~~~~

Cc: Mathias Nyman <mathias.nyman@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230204183651.never.663-kees@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/host/xhci-mvebu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-mvebu.c b/drivers/usb/host/xhci-mvebu.c
index f27d5c2c42f31..bb70dcc2f84f4 100644
--- a/drivers/usb/host/xhci-mvebu.c
+++ b/drivers/usb/host/xhci-mvebu.c
@@ -33,7 +33,7 @@ static void xhci_mvebu_mbus_config(void __iomem *base,
 
 	/* Program each DRAM CS in a seperate window */
 	for (win = 0; win < dram->num_cs; win++) {
-		const struct mbus_dram_window *cs = dram->cs + win;
+		const struct mbus_dram_window *cs = &dram->cs[win];
 
 		writel(((cs->size - 1) & 0xffff0000) | (cs->mbus_attr << 8) |
 		       (dram->mbus_dram_target_id << 4) | 1,
-- 
2.39.2

[PATCH AUTOSEL 5.4 16/20] USB: ene_usb6250: Allocate enough memory for full object

[Sasha Levin]

From: Kees Cook <keescook@chromium.org>

[ Upstream commit ce33e64c1788912976b61314b56935abd4bc97ef ]

The allocation of PageBuffer is 512 bytes in size, but the dereferencing
of struct ms_bootblock_idi (also size 512) happens at a calculated offset
within the allocation, which means the object could potentially extend
beyond the end of the allocation. Avoid this case by just allocating
enough space to catch any accesses beyond the end. Seen with GCC 13:

../drivers/usb/storage/ene_ub6250.c: In function 'ms_lib_process_bootblock':
../drivers/usb/storage/ene_ub6250.c:1050:44: warning: array subscript 'struct ms_bootblock_idi[0]' is partly outside array bounds of 'unsigned char[512]' [-Warray-bounds=]
 1050 |                         if (le16_to_cpu(idi->wIDIgeneralConfiguration) != MS_IDI_GENERAL_CONF)
      |                                            ^~
../include/uapi/linux/byteorder/little_endian.h:37:51: note: in definition of macro '__le16_to_cpu'
   37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
      |                                                   ^
../drivers/usb/storage/ene_ub6250.c:1050:29: note: in expansion of macro 'le16_to_cpu'
 1050 |                         if (le16_to_cpu(idi->wIDIgeneralConfiguration) != MS_IDI_GENERAL_CONF)
      |                             ^~~~~~~~~~~
In file included from ../drivers/usb/storage/ene_ub6250.c:5:
In function 'kmalloc',
    inlined from 'ms_lib_process_bootblock' at ../drivers/usb/storage/ene_ub6250.c:942:15:
../include/linux/slab.h:580:24: note: at offset [256, 512] into object of size 512 allocated by 'kmalloc_trace'
  580 |                 return kmalloc_trace(
      |                        ^~~~~~~~~~~~~~
  581 |                                 kmalloc_caches[kmalloc_type(flags)][index],
      |                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  582 |                                 flags, size);
      |                                 ~~~~~~~~~~~~

Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230204183546.never.849-kees@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/storage/ene_ub6250.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/storage/ene_ub6250.c b/drivers/usb/storage/ene_ub6250.c
index 9c984f3c7248a..b076260a2ca49 100644
--- a/drivers/usb/storage/ene_ub6250.c
+++ b/drivers/usb/storage/ene_ub6250.c
@@ -938,7 +938,7 @@ static int ms_lib_process_bootblock(struct us_data *us, u16 PhyBlock, u8 *PageDa
 	struct ms_lib_type_extdat ExtraData;
 	struct ene_ub6250_info *info = (struct ene_ub6250_info *) us->extra;
 
-	PageBuffer = kmalloc(MS_BYTES_PER_PAGE, GFP_KERNEL);
+	PageBuffer = kzalloc(MS_BYTES_PER_PAGE * 2, GFP_KERNEL);
 	if (PageBuffer == NULL)
 		return (u32)-1;
 
-- 
2.39.2