| Message ID | 20200620033007.1444705-5-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | Remove uninitialized_var() macro | expand |
On Fri, Jun 19, 2020 at 8:30 PM Kees Cook <keescook@chromium.org> wrote: > > Using uninitialized_var() is dangerous as it papers over real bugs[1] > (or can in the future), and suppresses unrelated compiler warnings (e.g. > "unused variable"). If the compiler thinks it is uninitialized, either > simply initialize the variable or make compiler changes. As a precursor > to removing[2] this[3] macro[4], just initialize this variable to NULL. > No later NULL deref is possible due to the early returns outside of the > (phy->rev >= 7 && phy->rev < 19) case, which explicitly tests for NULL. > > [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ > [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ > [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ > [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ > > Fixes: 58619b14d106 ("b43: move under broadcom vendor directory") > Signed-off-by: Kees Cook <keescook@chromium.org> I see three total uses of uninitialized_var() in this file, do we want to eliminate all of them? > --- > drivers/net/wireless/broadcom/b43/phy_n.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/broadcom/b43/phy_n.c b/drivers/net/wireless/broadcom/b43/phy_n.c > index c33b4235839d..46db91846007 100644 > --- a/drivers/net/wireless/broadcom/b43/phy_n.c > +++ b/drivers/net/wireless/broadcom/b43/phy_n.c > @@ -4222,7 +4222,7 @@ static void b43_nphy_tx_gain_table_upload(struct b43_wldev *dev) > u32 rfpwr_offset; > u8 pga_gain, pad_gain; > int i; > - const s16 *uninitialized_var(rf_pwr_offset_table); > + const s16 *rf_pwr_offset_table = NULL; > > table = b43_nphy_get_tx_gain_table(dev); > if (!table) > --
On Mon, Jun 22, 2020 at 10:04:18AM -0700, Nick Desaulniers wrote: > On Fri, Jun 19, 2020 at 8:30 PM Kees Cook <keescook@chromium.org> wrote: > > > > Using uninitialized_var() is dangerous as it papers over real bugs[1] > > (or can in the future), and suppresses unrelated compiler warnings (e.g. > > "unused variable"). If the compiler thinks it is uninitialized, either > > simply initialize the variable or make compiler changes. As a precursor > > to removing[2] this[3] macro[4], just initialize this variable to NULL. > > No later NULL deref is possible due to the early returns outside of the > > (phy->rev >= 7 && phy->rev < 19) case, which explicitly tests for NULL. > > > > [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ > > [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ > > [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ > > [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ > > > > Fixes: 58619b14d106 ("b43: move under broadcom vendor directory") > > Signed-off-by: Kees Cook <keescook@chromium.org> > > I see three total uses of uninitialized_var() in this file, do we want > to eliminate all of them? This is the only one that needed an explicit initialization -- all the others are handled in the treewide patch. I *could* split it out here, but I found it easier to keep the "no op" changes together in the treewide patch. -Kees > > > --- > > drivers/net/wireless/broadcom/b43/phy_n.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/net/wireless/broadcom/b43/phy_n.c b/drivers/net/wireless/broadcom/b43/phy_n.c > > index c33b4235839d..46db91846007 100644 > > --- a/drivers/net/wireless/broadcom/b43/phy_n.c > > +++ b/drivers/net/wireless/broadcom/b43/phy_n.c > > @@ -4222,7 +4222,7 @@ static void b43_nphy_tx_gain_table_upload(struct b43_wldev *dev) > > u32 rfpwr_offset; > > u8 pga_gain, pad_gain; > > int i; > > - const s16 *uninitialized_var(rf_pwr_offset_table); > > + const s16 *rf_pwr_offset_table = NULL; > > > > table = b43_nphy_get_tx_gain_table(dev); > > if (!table) > > -- > > -- > Thanks, > ~Nick Desaulniers
On Mon, Jun 22, 2020 at 2:04 PM Kees Cook <keescook@chromium.org> wrote: > > On Mon, Jun 22, 2020 at 10:04:18AM -0700, Nick Desaulniers wrote: > > On Fri, Jun 19, 2020 at 8:30 PM Kees Cook <keescook@chromium.org> wrote: > > > > > > Using uninitialized_var() is dangerous as it papers over real bugs[1] > > > (or can in the future), and suppresses unrelated compiler warnings (e.g. > > > "unused variable"). If the compiler thinks it is uninitialized, either > > > simply initialize the variable or make compiler changes. As a precursor > > > to removing[2] this[3] macro[4], just initialize this variable to NULL. > > > No later NULL deref is possible due to the early returns outside of the > > > (phy->rev >= 7 && phy->rev < 19) case, which explicitly tests for NULL. > > > > > > [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ > > > [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ > > > [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ > > > [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ > > > > > > Fixes: 58619b14d106 ("b43: move under broadcom vendor directory") > > > Signed-off-by: Kees Cook <keescook@chromium.org> > > > > I see three total uses of uninitialized_var() in this file, do we want > > to eliminate all of them? > > This is the only one that needed an explicit initialization -- all the > others are handled in the treewide patch. I *could* split it out here, > but I found it easier to keep the "no op" changes together in the > treewide patch. Ah, got it. Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > > -Kees > > > > > > --- > > > drivers/net/wireless/broadcom/b43/phy_n.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/net/wireless/broadcom/b43/phy_n.c b/drivers/net/wireless/broadcom/b43/phy_n.c > > > index c33b4235839d..46db91846007 100644 > > > --- a/drivers/net/wireless/broadcom/b43/phy_n.c > > > +++ b/drivers/net/wireless/broadcom/b43/phy_n.c > > > @@ -4222,7 +4222,7 @@ static void b43_nphy_tx_gain_table_upload(struct b43_wldev *dev) > > > u32 rfpwr_offset; > > > u8 pga_gain, pad_gain; > > > int i; > > > - const s16 *uninitialized_var(rf_pwr_offset_table); > > > + const s16 *rf_pwr_offset_table = NULL; > > > > > > table = b43_nphy_get_tx_gain_table(dev); > > > if (!table) > > > -- > > > > -- > > Thanks, > > ~Nick Desaulniers > > -- > Kees Cook
Kees Cook <keescook@chromium.org> wrote: > Using uninitialized_var() is dangerous as it papers over real bugs[1] > (or can in the future), and suppresses unrelated compiler warnings (e.g. > "unused variable"). If the compiler thinks it is uninitialized, either > simply initialize the variable or make compiler changes. As a precursor > to removing[2] this[3] macro[4], just initialize this variable to NULL. > No later NULL deref is possible due to the early returns outside of the > (phy->rev >= 7 && phy->rev < 19) case, which explicitly tests for NULL. > > [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ > [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ > [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ > [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ > > Fixes: 58619b14d106 ("b43: move under broadcom vendor directory") > Signed-off-by: Kees Cook <keescook@chromium.org> > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> 2 patches applied to wireless-drivers-next.git, thanks. 800e7a205a0f b43: Remove uninitialized_var() usage f8279dad4e36 rtlwifi: rtl8192cu: Remove uninitialized_var() usage
diff --git a/drivers/net/wireless/broadcom/b43/phy_n.c b/drivers/net/wireless/broadcom/b43/phy_n.c index c33b4235839d..46db91846007 100644 --- a/drivers/net/wireless/broadcom/b43/phy_n.c +++ b/drivers/net/wireless/broadcom/b43/phy_n.c @@ -4222,7 +4222,7 @@ static void b43_nphy_tx_gain_table_upload(struct b43_wldev *dev) u32 rfpwr_offset; u8 pga_gain, pad_gain; int i; - const s16 *uninitialized_var(rf_pwr_offset_table); + const s16 *rf_pwr_offset_table = NULL; table = b43_nphy_get_tx_gain_table(dev); if (!table)
Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. As a precursor to removing[2] this[3] macro[4], just initialize this variable to NULL. No later NULL deref is possible due to the early returns outside of the (phy->rev >= 7 && phy->rev < 19) case, which explicitly tests for NULL. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Fixes: 58619b14d106 ("b43: move under broadcom vendor directory") Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/net/wireless/broadcom/b43/phy_n.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)