| Message ID | 20220105173507.2420910-1-keescook@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/dp: Remove common Post Cursor2 register handling | expand |
On Wed, 05 Jan 2022, Kees Cook <keescook@chromium.org> wrote: > The link_status array was not large enough to read the Adjust Request > Post Cursor2 register, so remove the common helper function to avoid > an OOB read, found with a -Warray-bounds build: > > drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': > drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] > 59 | return link_status[r - DP_LANE0_1_STATUS]; > | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ > drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' > 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Replace the only user of the helper with an open-coded fetch and decode, > similar to drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c. > > Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments") > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> > Cc: Maxime Ripard <mripard@kernel.org> > Cc: Thomas Zimmermann <tzimmermann@suse.de> > Cc: David Airlie <airlied@linux.ie> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: dri-devel@lists.freedesktop.org > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > This is the alternative to: > https://lore.kernel.org/lkml/20211203084354.3105253-1-keescook@chromium.org/ > --- > drivers/gpu/drm/drm_dp_helper.c | 10 ---------- > drivers/gpu/drm/tegra/dp.c | 11 ++++++++++- > include/drm/drm_dp_helper.h | 2 -- > 3 files changed, 10 insertions(+), 13 deletions(-) > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > index 23f9073bc473..c9528aa62c9c 100644 > --- a/drivers/gpu/drm/drm_dp_helper.c > +++ b/drivers/gpu/drm/drm_dp_helper.c > @@ -144,16 +144,6 @@ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], > } > EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); > > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > - unsigned int lane) > -{ > - unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2; > - u8 value = dp_link_status(link_status, offset); > - > - return (value >> (lane << 1)) & 0x3; > -} > -EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); > - > static int __8b10b_clock_recovery_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) > { > if (rd_interval > 4) > diff --git a/drivers/gpu/drm/tegra/dp.c b/drivers/gpu/drm/tegra/dp.c > index 70dfb7d1dec5..f5535eb04c6b 100644 > --- a/drivers/gpu/drm/tegra/dp.c > +++ b/drivers/gpu/drm/tegra/dp.c > @@ -549,6 +549,15 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, > { > struct drm_dp_link_train_set *adjust = &link->train.adjust; > unsigned int i; > + u8 post_cursor; > + int err; > + > + err = drm_dp_dpcd_read(link->aux, DP_ADJUST_REQUEST_POST_CURSOR2, > + &post_cursor, sizeof(post_cursor)); There's a drm_dp_dpcd_readb() for the common 1-byte reads. Other than that, Reviewed-by: Jani Nikula <jani.nikula@intel.com> Though obviously that's not enough to actually merge to tegra. > + if (err < 0) { > + DRM_ERROR("failed to read post_cursor2: %d\n", err); > + post_cursor = 0; > + } > > for (i = 0; i < link->lanes; i++) { > adjust->voltage_swing[i] = > @@ -560,7 +569,7 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, > DP_TRAIN_PRE_EMPHASIS_SHIFT; > > adjust->post_cursor[i] = > - drm_dp_get_adjust_request_post_cursor(status, i); > + (post_cursor >> (i << 1)) & 0x3; > } > } > > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h > index 472dac376284..fdf3cf6ccc02 100644 > --- a/include/drm/drm_dp_helper.h > +++ b/include/drm/drm_dp_helper.h > @@ -1528,8 +1528,6 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI > int lane); > u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], > int lane); > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > - unsigned int lane); > > #define DP_BRANCH_OUI_HEADER_SIZE 0xc > #define DP_RECEIVER_CAP_SIZE 0xf
On Wed, Jan 05, 2022 at 08:00:50PM +0200, Jani Nikula wrote: > On Wed, 05 Jan 2022, Kees Cook <keescook@chromium.org> wrote: > > The link_status array was not large enough to read the Adjust Request > > Post Cursor2 register, so remove the common helper function to avoid > > an OOB read, found with a -Warray-bounds build: > > > > drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': > > drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] > > 59 | return link_status[r - DP_LANE0_1_STATUS]; > > | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ > > drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' > > 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > > | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > Replace the only user of the helper with an open-coded fetch and decode, > > similar to drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c. > > > > Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments") > > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> > > Cc: Maxime Ripard <mripard@kernel.org> > > Cc: Thomas Zimmermann <tzimmermann@suse.de> > > Cc: David Airlie <airlied@linux.ie> > > Cc: Daniel Vetter <daniel@ffwll.ch> > > Cc: dri-devel@lists.freedesktop.org > > Signed-off-by: Kees Cook <keescook@chromium.org> > > --- > > This is the alternative to: > > https://lore.kernel.org/lkml/20211203084354.3105253-1-keescook@chromium.org/ > > --- > > drivers/gpu/drm/drm_dp_helper.c | 10 ---------- > > drivers/gpu/drm/tegra/dp.c | 11 ++++++++++- > > include/drm/drm_dp_helper.h | 2 -- > > 3 files changed, 10 insertions(+), 13 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > > index 23f9073bc473..c9528aa62c9c 100644 > > --- a/drivers/gpu/drm/drm_dp_helper.c > > +++ b/drivers/gpu/drm/drm_dp_helper.c > > @@ -144,16 +144,6 @@ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], > > } > > EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); > > > > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > > - unsigned int lane) > > -{ > > - unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2; > > - u8 value = dp_link_status(link_status, offset); > > - > > - return (value >> (lane << 1)) & 0x3; > > -} > > -EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); > > - > > static int __8b10b_clock_recovery_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) > > { > > if (rd_interval > 4) > > diff --git a/drivers/gpu/drm/tegra/dp.c b/drivers/gpu/drm/tegra/dp.c > > index 70dfb7d1dec5..f5535eb04c6b 100644 > > --- a/drivers/gpu/drm/tegra/dp.c > > +++ b/drivers/gpu/drm/tegra/dp.c > > @@ -549,6 +549,15 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, > > { > > struct drm_dp_link_train_set *adjust = &link->train.adjust; > > unsigned int i; > > + u8 post_cursor; > > + int err; > > + > > + err = drm_dp_dpcd_read(link->aux, DP_ADJUST_REQUEST_POST_CURSOR2, > > + &post_cursor, sizeof(post_cursor)); > > There's a drm_dp_dpcd_readb() for the common 1-byte reads. Other than > that, > > Reviewed-by: Jani Nikula <jani.nikula@intel.com> Thanks! > > Though obviously that's not enough to actually merge to tegra. As in, "a review by Jani isn't sufficient to land via the tegra tree"? What should next steps be? -Kees > > > + if (err < 0) { > > + DRM_ERROR("failed to read post_cursor2: %d\n", err); > > + post_cursor = 0; > > + } > > > > for (i = 0; i < link->lanes; i++) { > > adjust->voltage_swing[i] = > > @@ -560,7 +569,7 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, > > DP_TRAIN_PRE_EMPHASIS_SHIFT; > > > > adjust->post_cursor[i] = > > - drm_dp_get_adjust_request_post_cursor(status, i); > > + (post_cursor >> (i << 1)) & 0x3; > > } > > } > > > > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h > > index 472dac376284..fdf3cf6ccc02 100644 > > --- a/include/drm/drm_dp_helper.h > > +++ b/include/drm/drm_dp_helper.h > > @@ -1528,8 +1528,6 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI > > int lane); > > u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], > > int lane); > > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > > - unsigned int lane); > > > > #define DP_BRANCH_OUI_HEADER_SIZE 0xc > > #define DP_RECEIVER_CAP_SIZE 0xf > > -- > Jani Nikula, Intel Open Source Graphics Center
On Wed, 05 Jan 2022, Kees Cook <keescook@chromium.org> wrote: > On Wed, Jan 05, 2022 at 08:00:50PM +0200, Jani Nikula wrote: >> On Wed, 05 Jan 2022, Kees Cook <keescook@chromium.org> wrote: >> > The link_status array was not large enough to read the Adjust Request >> > Post Cursor2 register, so remove the common helper function to avoid >> > an OOB read, found with a -Warray-bounds build: >> > >> > drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': >> > drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] >> > 59 | return link_status[r - DP_LANE0_1_STATUS]; >> > | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ >> > drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' >> > 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], >> > | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> > >> > Replace the only user of the helper with an open-coded fetch and decode, >> > similar to drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c. >> > >> > Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments") >> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> >> > Cc: Maxime Ripard <mripard@kernel.org> >> > Cc: Thomas Zimmermann <tzimmermann@suse.de> >> > Cc: David Airlie <airlied@linux.ie> >> > Cc: Daniel Vetter <daniel@ffwll.ch> >> > Cc: dri-devel@lists.freedesktop.org >> > Signed-off-by: Kees Cook <keescook@chromium.org> >> > --- >> > This is the alternative to: >> > https://lore.kernel.org/lkml/20211203084354.3105253-1-keescook@chromium.org/ >> > --- >> > drivers/gpu/drm/drm_dp_helper.c | 10 ---------- >> > drivers/gpu/drm/tegra/dp.c | 11 ++++++++++- >> > include/drm/drm_dp_helper.h | 2 -- >> > 3 files changed, 10 insertions(+), 13 deletions(-) >> > >> > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c >> > index 23f9073bc473..c9528aa62c9c 100644 >> > --- a/drivers/gpu/drm/drm_dp_helper.c >> > +++ b/drivers/gpu/drm/drm_dp_helper.c >> > @@ -144,16 +144,6 @@ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], >> > } >> > EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); >> > >> > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], >> > - unsigned int lane) >> > -{ >> > - unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2; >> > - u8 value = dp_link_status(link_status, offset); >> > - >> > - return (value >> (lane << 1)) & 0x3; >> > -} >> > -EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); >> > - >> > static int __8b10b_clock_recovery_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) >> > { >> > if (rd_interval > 4) >> > diff --git a/drivers/gpu/drm/tegra/dp.c b/drivers/gpu/drm/tegra/dp.c >> > index 70dfb7d1dec5..f5535eb04c6b 100644 >> > --- a/drivers/gpu/drm/tegra/dp.c >> > +++ b/drivers/gpu/drm/tegra/dp.c >> > @@ -549,6 +549,15 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, >> > { >> > struct drm_dp_link_train_set *adjust = &link->train.adjust; >> > unsigned int i; >> > + u8 post_cursor; >> > + int err; >> > + >> > + err = drm_dp_dpcd_read(link->aux, DP_ADJUST_REQUEST_POST_CURSOR2, >> > + &post_cursor, sizeof(post_cursor)); >> >> There's a drm_dp_dpcd_readb() for the common 1-byte reads. Other than >> that, >> >> Reviewed-by: Jani Nikula <jani.nikula@intel.com> > > Thanks! > >> >> Though obviously that's not enough to actually merge to tegra. > > As in, "a review by Jani isn't sufficient to land via the tegra tree"? Yeah. Or, in this case, via any tree, really. > What should next steps be? Get an ack from tegra and/or drm-misc maintainers. All the relevant folks and lists are in the recipients already. BR, Jani. > > -Kees > >> >> > + if (err < 0) { >> > + DRM_ERROR("failed to read post_cursor2: %d\n", err); >> > + post_cursor = 0; >> > + } >> > >> > for (i = 0; i < link->lanes; i++) { >> > adjust->voltage_swing[i] = >> > @@ -560,7 +569,7 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, >> > DP_TRAIN_PRE_EMPHASIS_SHIFT; >> > >> > adjust->post_cursor[i] = >> > - drm_dp_get_adjust_request_post_cursor(status, i); >> > + (post_cursor >> (i << 1)) & 0x3; >> > } >> > } >> > >> > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h >> > index 472dac376284..fdf3cf6ccc02 100644 >> > --- a/include/drm/drm_dp_helper.h >> > +++ b/include/drm/drm_dp_helper.h >> > @@ -1528,8 +1528,6 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI >> > int lane); >> > u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], >> > int lane); >> > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], >> > - unsigned int lane); >> > >> > #define DP_BRANCH_OUI_HEADER_SIZE 0xc >> > #define DP_RECEIVER_CAP_SIZE 0xf >> >> -- >> Jani Nikula, Intel Open Source Graphics Center
On 1/5/22 11:35, Kees Cook wrote: > The link_status array was not large enough to read the Adjust Request > Post Cursor2 register, so remove the common helper function to avoid > an OOB read, found with a -Warray-bounds build: > > drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': > drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] > 59 | return link_status[r - DP_LANE0_1_STATUS]; > | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ > drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' > 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Replace the only user of the helper with an open-coded fetch and decode, > similar to drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c. > > Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments") This should be tagged for -stable: Cc: stable@vger.kernel.org > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> > Cc: Maxime Ripard <mripard@kernel.org> > Cc: Thomas Zimmermann <tzimmermann@suse.de> > Cc: David Airlie <airlied@linux.ie> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: dri-devel@lists.freedesktop.org > Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Thanks -- Gustavo > --- > This is the alternative to: > https://lore.kernel.org/lkml/20211203084354.3105253-1-keescook@chromium.org/ > --- > drivers/gpu/drm/drm_dp_helper.c | 10 ---------- > drivers/gpu/drm/tegra/dp.c | 11 ++++++++++- > include/drm/drm_dp_helper.h | 2 -- > 3 files changed, 10 insertions(+), 13 deletions(-) > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > index 23f9073bc473..c9528aa62c9c 100644 > --- a/drivers/gpu/drm/drm_dp_helper.c > +++ b/drivers/gpu/drm/drm_dp_helper.c > @@ -144,16 +144,6 @@ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], > } > EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); > > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > - unsigned int lane) > -{ > - unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2; > - u8 value = dp_link_status(link_status, offset); > - > - return (value >> (lane << 1)) & 0x3; > -} > -EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); > - > static int __8b10b_clock_recovery_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) > { > if (rd_interval > 4) > diff --git a/drivers/gpu/drm/tegra/dp.c b/drivers/gpu/drm/tegra/dp.c > index 70dfb7d1dec5..f5535eb04c6b 100644 > --- a/drivers/gpu/drm/tegra/dp.c > +++ b/drivers/gpu/drm/tegra/dp.c > @@ -549,6 +549,15 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, > { > struct drm_dp_link_train_set *adjust = &link->train.adjust; > unsigned int i; > + u8 post_cursor; > + int err; > + > + err = drm_dp_dpcd_read(link->aux, DP_ADJUST_REQUEST_POST_CURSOR2, > + &post_cursor, sizeof(post_cursor)); > + if (err < 0) { > + DRM_ERROR("failed to read post_cursor2: %d\n", err); > + post_cursor = 0; > + } > > for (i = 0; i < link->lanes; i++) { > adjust->voltage_swing[i] = > @@ -560,7 +569,7 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, > DP_TRAIN_PRE_EMPHASIS_SHIFT; > > adjust->post_cursor[i] = > - drm_dp_get_adjust_request_post_cursor(status, i); > + (post_cursor >> (i << 1)) & 0x3; > } > } > > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h > index 472dac376284..fdf3cf6ccc02 100644 > --- a/include/drm/drm_dp_helper.h > +++ b/include/drm/drm_dp_helper.h > @@ -1528,8 +1528,6 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI > int lane); > u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], > int lane); > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > - unsigned int lane); > > #define DP_BRANCH_OUI_HEADER_SIZE 0xc > #define DP_RECEIVER_CAP_SIZE 0xf >
On Tue, Jan 18, 2022 at 01:11:48PM -0600, Gustavo A. R. Silva wrote: > > > On 1/5/22 11:35, Kees Cook wrote: > > The link_status array was not large enough to read the Adjust Request > > Post Cursor2 register, so remove the common helper function to avoid > > an OOB read, found with a -Warray-bounds build: > > > > drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': > > drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] > > 59 | return link_status[r - DP_LANE0_1_STATUS]; > > | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ > > drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' > > 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > > | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > Replace the only user of the helper with an open-coded fetch and decode, > > similar to drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c. > > > > Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments") > > This should be tagged for -stable: > > Cc: stable@vger.kernel.org Ah yeah, good point. Added. > > > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> > > Cc: Maxime Ripard <mripard@kernel.org> > > Cc: Thomas Zimmermann <tzimmermann@suse.de> > > Cc: David Airlie <airlied@linux.ie> > > Cc: Daniel Vetter <daniel@ffwll.ch> > > Cc: dri-devel@lists.freedesktop.org > > Signed-off-by: Kees Cook <keescook@chromium.org> > > Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Thanks! -Kees > > Thanks > -- > Gustavo > > > --- > > This is the alternative to: > > https://lore.kernel.org/lkml/20211203084354.3105253-1-keescook@chromium.org/ > > --- > > drivers/gpu/drm/drm_dp_helper.c | 10 ---------- > > drivers/gpu/drm/tegra/dp.c | 11 ++++++++++- > > include/drm/drm_dp_helper.h | 2 -- > > 3 files changed, 10 insertions(+), 13 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > > index 23f9073bc473..c9528aa62c9c 100644 > > --- a/drivers/gpu/drm/drm_dp_helper.c > > +++ b/drivers/gpu/drm/drm_dp_helper.c > > @@ -144,16 +144,6 @@ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], > > } > > EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); > > > > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > > - unsigned int lane) > > -{ > > - unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2; > > - u8 value = dp_link_status(link_status, offset); > > - > > - return (value >> (lane << 1)) & 0x3; > > -} > > -EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); > > - > > static int __8b10b_clock_recovery_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) > > { > > if (rd_interval > 4) > > diff --git a/drivers/gpu/drm/tegra/dp.c b/drivers/gpu/drm/tegra/dp.c > > index 70dfb7d1dec5..f5535eb04c6b 100644 > > --- a/drivers/gpu/drm/tegra/dp.c > > +++ b/drivers/gpu/drm/tegra/dp.c > > @@ -549,6 +549,15 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, > > { > > struct drm_dp_link_train_set *adjust = &link->train.adjust; > > unsigned int i; > > + u8 post_cursor; > > + int err; > > + > > + err = drm_dp_dpcd_read(link->aux, DP_ADJUST_REQUEST_POST_CURSOR2, > > + &post_cursor, sizeof(post_cursor)); > > + if (err < 0) { > > + DRM_ERROR("failed to read post_cursor2: %d\n", err); > > + post_cursor = 0; > > + } > > > > for (i = 0; i < link->lanes; i++) { > > adjust->voltage_swing[i] = > > @@ -560,7 +569,7 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, > > DP_TRAIN_PRE_EMPHASIS_SHIFT; > > > > adjust->post_cursor[i] = > > - drm_dp_get_adjust_request_post_cursor(status, i); > > + (post_cursor >> (i << 1)) & 0x3; > > } > > } > > > > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h > > index 472dac376284..fdf3cf6ccc02 100644 > > --- a/include/drm/drm_dp_helper.h > > +++ b/include/drm/drm_dp_helper.h > > @@ -1528,8 +1528,6 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI > > int lane); > > u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], > > int lane); > > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > > - unsigned int lane); > > > > #define DP_BRANCH_OUI_HEADER_SIZE 0xc > > #define DP_RECEIVER_CAP_SIZE 0xf > >
Ping, This is a OOB read fix. Can someone please pick this up? -Kees On Wed, Jan 05, 2022 at 09:35:07AM -0800, Kees Cook wrote: > The link_status array was not large enough to read the Adjust Request > Post Cursor2 register, so remove the common helper function to avoid > an OOB read, found with a -Warray-bounds build: > > drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': > drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] > 59 | return link_status[r - DP_LANE0_1_STATUS]; > | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ > drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' > 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Replace the only user of the helper with an open-coded fetch and decode, > similar to drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c. > > Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments") > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> > Cc: Maxime Ripard <mripard@kernel.org> > Cc: Thomas Zimmermann <tzimmermann@suse.de> > Cc: David Airlie <airlied@linux.ie> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: dri-devel@lists.freedesktop.org > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > This is the alternative to: > https://lore.kernel.org/lkml/20211203084354.3105253-1-keescook@chromium.org/ > --- > drivers/gpu/drm/drm_dp_helper.c | 10 ---------- > drivers/gpu/drm/tegra/dp.c | 11 ++++++++++- > include/drm/drm_dp_helper.h | 2 -- > 3 files changed, 10 insertions(+), 13 deletions(-) > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > index 23f9073bc473..c9528aa62c9c 100644 > --- a/drivers/gpu/drm/drm_dp_helper.c > +++ b/drivers/gpu/drm/drm_dp_helper.c > @@ -144,16 +144,6 @@ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], > } > EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); > > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > - unsigned int lane) > -{ > - unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2; > - u8 value = dp_link_status(link_status, offset); > - > - return (value >> (lane << 1)) & 0x3; > -} > -EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); > - > static int __8b10b_clock_recovery_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) > { > if (rd_interval > 4) > diff --git a/drivers/gpu/drm/tegra/dp.c b/drivers/gpu/drm/tegra/dp.c > index 70dfb7d1dec5..f5535eb04c6b 100644 > --- a/drivers/gpu/drm/tegra/dp.c > +++ b/drivers/gpu/drm/tegra/dp.c > @@ -549,6 +549,15 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, > { > struct drm_dp_link_train_set *adjust = &link->train.adjust; > unsigned int i; > + u8 post_cursor; > + int err; > + > + err = drm_dp_dpcd_read(link->aux, DP_ADJUST_REQUEST_POST_CURSOR2, > + &post_cursor, sizeof(post_cursor)); > + if (err < 0) { > + DRM_ERROR("failed to read post_cursor2: %d\n", err); > + post_cursor = 0; > + } > > for (i = 0; i < link->lanes; i++) { > adjust->voltage_swing[i] = > @@ -560,7 +569,7 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, > DP_TRAIN_PRE_EMPHASIS_SHIFT; > > adjust->post_cursor[i] = > - drm_dp_get_adjust_request_post_cursor(status, i); > + (post_cursor >> (i << 1)) & 0x3; > } > } > > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h > index 472dac376284..fdf3cf6ccc02 100644 > --- a/include/drm/drm_dp_helper.h > +++ b/include/drm/drm_dp_helper.h > @@ -1528,8 +1528,6 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI > int lane); > u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], > int lane); > -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], > - unsigned int lane); > > #define DP_BRANCH_OUI_HEADER_SIZE 0xc > #define DP_RECEIVER_CAP_SIZE 0xf > -- > 2.30.2 >
On Fri, 04 Feb 2022, Kees Cook <keescook@chromium.org> wrote: > Ping, > > This is a OOB read fix. Can someone please pick this up? Daniel? Thierry? As I said, I reviewed this but I'm not comfortable applying patches that change the functionality of drivers I don't maintain. BR, Jani. > > -Kees > > On Wed, Jan 05, 2022 at 09:35:07AM -0800, Kees Cook wrote: >> The link_status array was not large enough to read the Adjust Request >> Post Cursor2 register, so remove the common helper function to avoid >> an OOB read, found with a -Warray-bounds build: >> >> drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': >> drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] >> 59 | return link_status[r - DP_LANE0_1_STATUS]; >> | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ >> drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' >> 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], >> | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> >> Replace the only user of the helper with an open-coded fetch and decode, >> similar to drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c. >> >> Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments") >> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> >> Cc: Maxime Ripard <mripard@kernel.org> >> Cc: Thomas Zimmermann <tzimmermann@suse.de> >> Cc: David Airlie <airlied@linux.ie> >> Cc: Daniel Vetter <daniel@ffwll.ch> >> Cc: dri-devel@lists.freedesktop.org >> Signed-off-by: Kees Cook <keescook@chromium.org> >> --- >> This is the alternative to: >> https://lore.kernel.org/lkml/20211203084354.3105253-1-keescook@chromium.org/ >> --- >> drivers/gpu/drm/drm_dp_helper.c | 10 ---------- >> drivers/gpu/drm/tegra/dp.c | 11 ++++++++++- >> include/drm/drm_dp_helper.h | 2 -- >> 3 files changed, 10 insertions(+), 13 deletions(-) >> >> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c >> index 23f9073bc473..c9528aa62c9c 100644 >> --- a/drivers/gpu/drm/drm_dp_helper.c >> +++ b/drivers/gpu/drm/drm_dp_helper.c >> @@ -144,16 +144,6 @@ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], >> } >> EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); >> >> -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], >> - unsigned int lane) >> -{ >> - unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2; >> - u8 value = dp_link_status(link_status, offset); >> - >> - return (value >> (lane << 1)) & 0x3; >> -} >> -EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); >> - >> static int __8b10b_clock_recovery_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) >> { >> if (rd_interval > 4) >> diff --git a/drivers/gpu/drm/tegra/dp.c b/drivers/gpu/drm/tegra/dp.c >> index 70dfb7d1dec5..f5535eb04c6b 100644 >> --- a/drivers/gpu/drm/tegra/dp.c >> +++ b/drivers/gpu/drm/tegra/dp.c >> @@ -549,6 +549,15 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, >> { >> struct drm_dp_link_train_set *adjust = &link->train.adjust; >> unsigned int i; >> + u8 post_cursor; >> + int err; >> + >> + err = drm_dp_dpcd_read(link->aux, DP_ADJUST_REQUEST_POST_CURSOR2, >> + &post_cursor, sizeof(post_cursor)); >> + if (err < 0) { >> + DRM_ERROR("failed to read post_cursor2: %d\n", err); >> + post_cursor = 0; >> + } >> >> for (i = 0; i < link->lanes; i++) { >> adjust->voltage_swing[i] = >> @@ -560,7 +569,7 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, >> DP_TRAIN_PRE_EMPHASIS_SHIFT; >> >> adjust->post_cursor[i] = >> - drm_dp_get_adjust_request_post_cursor(status, i); >> + (post_cursor >> (i << 1)) & 0x3; >> } >> } >> >> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h >> index 472dac376284..fdf3cf6ccc02 100644 >> --- a/include/drm/drm_dp_helper.h >> +++ b/include/drm/drm_dp_helper.h >> @@ -1528,8 +1528,6 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI >> int lane); >> u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], >> int lane); >> -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], >> - unsigned int lane); >> >> #define DP_BRANCH_OUI_HEADER_SIZE 0xc >> #define DP_RECEIVER_CAP_SIZE 0xf >> -- >> 2.30.2 >>
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 23f9073bc473..c9528aa62c9c 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -144,16 +144,6 @@ u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], } EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], - unsigned int lane) -{ - unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2; - u8 value = dp_link_status(link_status, offset); - - return (value >> (lane << 1)) & 0x3; -} -EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor); - static int __8b10b_clock_recovery_delay_us(const struct drm_dp_aux *aux, u8 rd_interval) { if (rd_interval > 4) diff --git a/drivers/gpu/drm/tegra/dp.c b/drivers/gpu/drm/tegra/dp.c index 70dfb7d1dec5..f5535eb04c6b 100644 --- a/drivers/gpu/drm/tegra/dp.c +++ b/drivers/gpu/drm/tegra/dp.c @@ -549,6 +549,15 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, { struct drm_dp_link_train_set *adjust = &link->train.adjust; unsigned int i; + u8 post_cursor; + int err; + + err = drm_dp_dpcd_read(link->aux, DP_ADJUST_REQUEST_POST_CURSOR2, + &post_cursor, sizeof(post_cursor)); + if (err < 0) { + DRM_ERROR("failed to read post_cursor2: %d\n", err); + post_cursor = 0; + } for (i = 0; i < link->lanes; i++) { adjust->voltage_swing[i] = @@ -560,7 +569,7 @@ static void drm_dp_link_get_adjustments(struct drm_dp_link *link, DP_TRAIN_PRE_EMPHASIS_SHIFT; adjust->post_cursor[i] = - drm_dp_get_adjust_request_post_cursor(status, i); + (post_cursor >> (i << 1)) & 0x3; } } diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 472dac376284..fdf3cf6ccc02 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1528,8 +1528,6 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI int lane); u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], int lane); -u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], - unsigned int lane); #define DP_BRANCH_OUI_HEADER_SIZE 0xc #define DP_RECEIVER_CAP_SIZE 0xf
The link_status array was not large enough to read the Adjust Request Post Cursor2 register, so remove the common helper function to avoid an OOB read, found with a -Warray-bounds build: drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] 59 | return link_status[r - DP_LANE0_1_STATUS]; | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Replace the only user of the helper with an open-coded fetch and decode, similar to drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c. Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments") Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: dri-devel@lists.freedesktop.org Signed-off-by: Kees Cook <keescook@chromium.org> --- This is the alternative to: https://lore.kernel.org/lkml/20211203084354.3105253-1-keescook@chromium.org/ --- drivers/gpu/drm/drm_dp_helper.c | 10 ---------- drivers/gpu/drm/tegra/dp.c | 11 ++++++++++- include/drm/drm_dp_helper.h | 2 -- 3 files changed, 10 insertions(+), 13 deletions(-)