* [PATCH] usb: host: xhci: mvebu: Iterate over array indexes instead of using pointer math
@ 2023-02-04 18:36 Kees Cook
0 siblings, 0 replies; only message in thread
From: Kees Cook @ 2023-02-04 18:36 UTC (permalink / raw
To: Mathias Nyman
Cc: Kees Cook, Greg Kroah-Hartman, linux-usb, linux-kernel,
linux-hardening
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>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.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 60651a50770f..87f1597a0e5a 100644
--- a/drivers/usb/host/xhci-mvebu.c
+++ b/drivers/usb/host/xhci-mvebu.c
@@ -32,7 +32,7 @@ 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,
--
2.34.1
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2023-02-04 18:36 [PATCH] usb: host: xhci: mvebu: Iterate over array indexes instead of using pointer math Kees Cook
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