| Message ID | 20240123002814.1396804-62-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: Brian Norris <briannorris@chromium.org> > Cc: Kalle Valo <kvalo@kernel.org> > Cc: "Jonas Dreßler" <verdre@v0yd.nl> > Cc: Dmitry Antipov <dmantipov@yandex.ru> > Cc: Tsuchiya Yuto <kitakar@gmail.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>
diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c index 5f997becdbaa..e69347e65f0e 100644 --- a/drivers/net/wireless/marvell/mwifiex/pcie.c +++ b/drivers/net/wireless/marvell/mwifiex/pcie.c @@ -2086,7 +2086,7 @@ static int mwifiex_extract_wifi_fw(struct mwifiex_adapter *adapter, switch (dnld_cmd) { case MWIFIEX_FW_DNLD_CMD_1: - if (offset + data_len < data_len) { + if (add_would_overflow(data_len, offset)) { mwifiex_dbg(adapter, ERROR, "bad FW parse\n"); ret = -1; goto done; @@ -2110,7 +2110,7 @@ static int mwifiex_extract_wifi_fw(struct mwifiex_adapter *adapter, case MWIFIEX_FW_DNLD_CMD_5: first_cmd = true; /* Check for integer overflow */ - if (offset + data_len < data_len) { + if (add_would_overflow(data_len, offset)) { mwifiex_dbg(adapter, ERROR, "bad FW parse\n"); ret = -1; goto done; @@ -2120,7 +2120,7 @@ static int mwifiex_extract_wifi_fw(struct mwifiex_adapter *adapter, case MWIFIEX_FW_DNLD_CMD_6: first_cmd = true; /* Check for integer overflow */ - if (offset + data_len < data_len) { + if (add_would_overflow(data_len, offset)) { mwifiex_dbg(adapter, ERROR, "bad FW parse\n"); ret = -1; goto done;
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: Brian Norris <briannorris@chromium.org> Cc: Kalle Valo <kvalo@kernel.org> Cc: "Jonas Dreßler" <verdre@v0yd.nl> Cc: Dmitry Antipov <dmantipov@yandex.ru> Cc: Tsuchiya Yuto <kitakar@gmail.com> Cc: linux-wireless@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/net/wireless/marvell/mwifiex/pcie.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)