| Message ID | 20240123002814.1396804-41-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | overflow: Refactor open-coded arithmetic wrap-around | expand |
Kees Cook <keescook@chromium.org> writes: > In an effort to separate intentional arithmetic wrap-around from > unexpected wrap-around, we need to refactor places that depend on this > kind of math. One of the most common code patterns of this is: > > VAR + value < VAR > > Notably, this is considered "undefined behavior" for signed and pointer > types, which the kernel works around by using the -fno-strict-overflow > option in the build[1] (which used to just be -fwrapv). Regardless, we > want to get the kernel source to the position where we can meaningfully > instrument arithmetic wrap-around conditions and catch them when they > are unexpected, regardless of whether they are signed[2], unsigned[3], > or pointer[4] types. > > Refactor open-coded wrap-around addition test to use add_would_overflow(). > This paves the way to enabling the wrap-around sanitizers in the future. > > Link: https://git.kernel.org/linus/68df3755e383e6fecf2354a67b08f92f18536594 [1] > Link: https://github.com/KSPP/linux/issues/26 [2] > Link: https://github.com/KSPP/linux/issues/27 [3] > Link: https://github.com/KSPP/linux/issues/344 [4] > Cc: Kalle Valo <kvalo@kernel.org> > Cc: Johannes Berg <johannes.berg@intel.com> > Cc: Max Chen <mxchen@codeaurora.org> > Cc: Yang Shen <shenyang39@huawei.com> > Cc: linux-wireless@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> I assume this goes via some other tree than wireless-next so: Acked-by: Kalle Valo <kvalo@kernel.org>
Kees Cook <keescook@chromium.org> wrote: > In an effort to separate intentional arithmetic wrap-around from > unexpected wrap-around, we need to refactor places that depend on this > kind of math. One of the most common code patterns of this is: > > VAR + value < VAR > > Notably, this is considered "undefined behavior" for signed and pointer > types, which the kernel works around by using the -fno-strict-overflow > option in the build[1] (which used to just be -fwrapv). Regardless, we > want to get the kernel source to the position where we can meaningfully > instrument arithmetic wrap-around conditions and catch them when they > are unexpected, regardless of whether they are signed[2], unsigned[3], > or pointer[4] types. > > Refactor open-coded wrap-around addition test to use add_would_overflow(). > This paves the way to enabling the wrap-around sanitizers in the future. > > Link: https://git.kernel.org/linus/68df3755e383e6fecf2354a67b08f92f18536594 [1] > Link: https://github.com/KSPP/linux/issues/26 [2] > Link: https://github.com/KSPP/linux/issues/27 [3] > Link: https://github.com/KSPP/linux/issues/344 [4] > Cc: Kalle Valo <kvalo@kernel.org> > Cc: Johannes Berg <johannes.berg@intel.com> > Cc: Max Chen <mxchen@codeaurora.org> > Cc: Yang Shen <shenyang39@huawei.com> > Cc: linux-wireless@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> > Acked-by: Kalle Valo <kvalo@kernel.org> If you can edit before commit please add "wifi:" prefix to the wireless patches: ERROR: 'wifi:' prefix missing: '[PATCH 41/82] wil6210: Refactor intentional wrap-around test' ERROR: 'wifi:' prefix missing: '[PATCH 62/82] mwifiex: pcie: Refactor intentional wrap-around test' 2 patches set to Not Applicable. 13526631 [41/82] wil6210: Refactor intentional wrap-around test 13526632 [62/82] mwifiex: pcie: Refactor intentional wrap-around test
On Tue, Jan 23, 2024 at 11:50:34AM +0000, Kalle Valo wrote: > Kees Cook <keescook@chromium.org> wrote: > > > In an effort to separate intentional arithmetic wrap-around from > > unexpected wrap-around, we need to refactor places that depend on this > > kind of math. One of the most common code patterns of this is: > > > > VAR + value < VAR > > > > Notably, this is considered "undefined behavior" for signed and pointer > > types, which the kernel works around by using the -fno-strict-overflow > > option in the build[1] (which used to just be -fwrapv). Regardless, we > > want to get the kernel source to the position where we can meaningfully > > instrument arithmetic wrap-around conditions and catch them when they > > are unexpected, regardless of whether they are signed[2], unsigned[3], > > or pointer[4] types. > > > > Refactor open-coded wrap-around addition test to use add_would_overflow(). > > This paves the way to enabling the wrap-around sanitizers in the future. > > > > Link: https://git.kernel.org/linus/68df3755e383e6fecf2354a67b08f92f18536594 [1] > > Link: https://github.com/KSPP/linux/issues/26 [2] > > Link: https://github.com/KSPP/linux/issues/27 [3] > > Link: https://github.com/KSPP/linux/issues/344 [4] > > Cc: Kalle Valo <kvalo@kernel.org> > > Cc: Johannes Berg <johannes.berg@intel.com> > > Cc: Max Chen <mxchen@codeaurora.org> > > Cc: Yang Shen <shenyang39@huawei.com> > > Cc: linux-wireless@vger.kernel.org > > Signed-off-by: Kees Cook <keescook@chromium.org> > > Acked-by: Kalle Valo <kvalo@kernel.org> > > If you can edit before commit please add "wifi:" prefix to the wireless patches: > > ERROR: 'wifi:' prefix missing: '[PATCH 41/82] wil6210: Refactor intentional wrap-around test' > ERROR: 'wifi:' prefix missing: '[PATCH 62/82] mwifiex: pcie: Refactor intentional wrap-around test' Ah yes, thank you! I will adjust them. -Kees > > 2 patches set to Not Applicable. > > 13526631 [41/82] wil6210: Refactor intentional wrap-around test > 13526632 [62/82] mwifiex: pcie: Refactor intentional wrap-around test > > -- > https://patchwork.kernel.org/project/linux-wireless/patch/20240123002814.1396804-41-keescook@chromium.org/ > > https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches >
diff --git a/drivers/net/wireless/ath/wil6210/wmi.c b/drivers/net/wireless/ath/wil6210/wmi.c index 6fdb77d4c59e..3b3c991f77e9 100644 --- a/drivers/net/wireless/ath/wil6210/wmi.c +++ b/drivers/net/wireless/ath/wil6210/wmi.c @@ -286,7 +286,7 @@ void __iomem *wmi_buffer_block(struct wil6210_priv *wil, __le32 ptr_, u32 size) off = HOSTADDR(ptr); if (off > wil->bar_size - 4) return NULL; - if (size && ((off + size > wil->bar_size) || (off + size < off))) + if (size && ((off + size > wil->bar_size) || (add_would_overflow(off, size)))) return NULL; return wil->csr + off;
In an effort to separate intentional arithmetic wrap-around from unexpected wrap-around, we need to refactor places that depend on this kind of math. One of the most common code patterns of this is: VAR + value < VAR Notably, this is considered "undefined behavior" for signed and pointer types, which the kernel works around by using the -fno-strict-overflow option in the build[1] (which used to just be -fwrapv). Regardless, we want to get the kernel source to the position where we can meaningfully instrument arithmetic wrap-around conditions and catch them when they are unexpected, regardless of whether they are signed[2], unsigned[3], or pointer[4] types. Refactor open-coded wrap-around addition test to use add_would_overflow(). This paves the way to enabling the wrap-around sanitizers in the future. Link: https://git.kernel.org/linus/68df3755e383e6fecf2354a67b08f92f18536594 [1] Link: https://github.com/KSPP/linux/issues/26 [2] Link: https://github.com/KSPP/linux/issues/27 [3] Link: https://github.com/KSPP/linux/issues/344 [4] Cc: Kalle Valo <kvalo@kernel.org> Cc: Johannes Berg <johannes.berg@intel.com> Cc: Max Chen <mxchen@codeaurora.org> Cc: Yang Shen <shenyang39@huawei.com> Cc: linux-wireless@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/net/wireless/ath/wil6210/wmi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)