In imx_pd_bind, the duplicated memory for imxpd->edid via kmemdup should be released in drm_of_find_panel_or_bridge or imx_pd_register fail.
Fixes: ebc944613567 ("drm: convert drivers to use drm_of_find_panel_or_bridge") Fixes: 19022aaae677 ("staging: drm/imx: Add parallel display support") Signed-off-by: Navid Emamdoost navid.emamdoost@gmail.com --- drivers/gpu/drm/imx/parallel-display.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c index e7ce17503ae1..9522d2cb0ad5 100644 --- a/drivers/gpu/drm/imx/parallel-display.c +++ b/drivers/gpu/drm/imx/parallel-display.c @@ -227,14 +227,18 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data)
/* port@1 is the output port */ ret = drm_of_find_panel_or_bridge(np, 1, 0, &imxpd->panel, &imxpd->bridge); - if (ret && ret != -ENODEV) + if (ret && ret != -ENODEV) { + kfree(imxpd->edid); return ret; + }
imxpd->dev = dev;
ret = imx_pd_register(drm, imxpd); - if (ret) + if (ret) { + kfree(imxpd->edid); return ret; + }
dev_set_drvdata(dev, imxpd);
In imx_pd_bind, the duplicated memory for imxpd->edid via kmemdup should be released in drm_of_find_panel_or_bridge or imx_pd_register fail.
Please improve this change description.
+++ b/drivers/gpu/drm/imx/parallel-display.c @@ -227,14 +227,18 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data)
/* port@1 is the output port */ ret = drm_of_find_panel_or_bridge(np, 1, 0, &imxpd->panel, &imxpd->bridge);
- if (ret && ret != -ENODEV)
if (ret && ret != -ENODEV) {
kfree(imxpd->edid);return ret;
}
imxpd->dev = dev;
Please use a jump target here instead of adding duplicate source code for the completion of exception handling.
if (ret && ret != -ENODEV) - return ret; + goto free_edid;
…
+free_edid: + kfree(imxpd->edid); + return ret;
Regards, Markus
+free_edid:
- kfree(imxpd->edid);
- return ret;
I have taken another look at this change idea. Can the function call “devm_kfree(dev, imxpd)” become relevant also at this place?
Would you like to combine it with the update suggestion “Fix error handling for a kmemdup() call in imx_pd_bind()”? https://lore.kernel.org/r/3fd6aa8b-2529-7ff5-3e19-05267101b2a4@web.de/ https://lore.kernel.org/patchwork/patch/1138912/ https://lkml.org/lkml/2019/10/12/87
Regards, Markus
No, that is not correct! You should not try to free imxpd here as it is a resource-managed allocation via devm_kzalloc(). It means memory allocated with this function is automatically freed on driver detach. So, this patch introduces a double-free.
On Sat, Oct 12, 2019 at 6:54 AM Markus Elfring Markus.Elfring@web.de wrote:
+free_edid:
kfree(imxpd->edid);return ret;I have taken another look at this change idea. Can the function call “devm_kfree(dev, imxpd)” become relevant also at this place?
Would you like to combine it with the update suggestion “Fix error handling for a kmemdup() call in imx_pd_bind()”? https://lore.kernel.org/r/3fd6aa8b-2529-7ff5-3e19-05267101b2a4@web.de/ https://lore.kernel.org/patchwork/patch/1138912/ https://lkml.org/lkml/2019/10/12/87
Regards, Markus
I have taken another look also at the implementation of the function “imx_pd_bind”. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/driv... https://elixir.bootlin.com/linux/v5.4-rc1/source/drivers/gpu/drm/imx/paralle...
Now I find an unchecked call of the function “kmemdup” suspicious. Will this detail trigger further software development considerations?
Regards, Markus
Hi Markus,
I agree with you, kmemdup may fail so a null check seems necessary there.
On Sun, Oct 6, 2019 at 4:33 AM Markus Elfring Markus.Elfring@web.de wrote:
I have taken another look also at the implementation of the function “imx_pd_bind”. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/driv... https://elixir.bootlin.com/linux/v5.4-rc1/source/drivers/gpu/drm/imx/paralle...
Now I find an unchecked call of the function “kmemdup” suspicious. Will this detail trigger further software development considerations?
Regards, Markus
I agree with you, kmemdup may fail so a null check seems necessary there.
Would this place (and similar ones) be pointed out for further considerations also by the source code analysis tool which your software research group seems to be developing? https://github.com/umnsec/cheq/
Regards, Markus
From: Markus Elfring elfring@users.sourceforge.net Date: Sat, 12 Oct 2019 10:45:45 +0200
Two update suggestions were taken into account from static source code analysis.
Markus Elfring (2): Fix error handling for a kmemdup() call in imx_pd_bind() Fix error handling for a kmemdup() call in imx_ldb_panel_ddc()
drivers/gpu/drm/imx/imx-ldb.c | 2 ++ drivers/gpu/drm/imx/parallel-display.c | 7 ++++++- 2 files changed, 8 insertions(+), 1 deletion(-)
-- 2.23.0
From: Markus Elfring elfring@users.sourceforge.net Date: Sat, 12 Oct 2019 10:30:21 +0200
The return value from a call of the function “kmemdup” was not checked in this function implementation. Thus add the corresponding error handling.
Fixes: 19022aaae677dfa171a719e9d1ff04823ce65a65 ("staging: drm/imx: Add parallel display support") Signed-off-by: Markus Elfring elfring@users.sourceforge.net --- drivers/gpu/drm/imx/parallel-display.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c index 35518e5de356..39c4798f56b6 100644 --- a/drivers/gpu/drm/imx/parallel-display.c +++ b/drivers/gpu/drm/imx/parallel-display.c @@ -210,8 +210,13 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data) return -ENOMEM;
edidp = of_get_property(np, "edid", &imxpd->edid_len); - if (edidp) + if (edidp) { imxpd->edid = kmemdup(edidp, imxpd->edid_len, GFP_KERNEL); + if (!imxpd->edid) { + devm_kfree(dev, imxpd); + return -ENOMEM; + } + }
ret = of_property_read_string(np, "interface-pix-fmt", &fmt); if (!ret) { -- 2.23.0
On Sat, Oct 12, 2019 at 4:07 AM Markus Elfring Markus.Elfring@web.de wrote:
From: Markus Elfring elfring@users.sourceforge.net Date: Sat, 12 Oct 2019 10:30:21 +0200
The return value from a call of the function “kmemdup” was not checked in this function implementation. Thus add the corresponding error handling.
Fixes: 19022aaae677dfa171a719e9d1ff04823ce65a65 ("staging: drm/imx: Add parallel display support") Signed-off-by: Markus Elfring elfring@users.sourceforge.net
drivers/gpu/drm/imx/parallel-display.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c index 35518e5de356..39c4798f56b6 100644 --- a/drivers/gpu/drm/imx/parallel-display.c +++ b/drivers/gpu/drm/imx/parallel-display.c @@ -210,8 +210,13 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data) return -ENOMEM;
edidp = of_get_property(np, "edid", &imxpd->edid_len);
if (edidp)
if (edidp) { imxpd->edid = kmemdup(edidp, imxpd->edid_len, GFP_KERNEL);if (!imxpd->edid) {devm_kfree(dev, imxpd);
You should not try to free imxpd here as it is a resource-managed allocation via devm_kzalloc(). It means memory allocated with this function is automatically freed on driver detach. So, this patch introduces a double-free.
return -ENOMEM;}} ret = of_property_read_string(np, "interface-pix-fmt", &fmt); if (!ret) {-- 2.23.0
On Sat, 12 Oct 2019, Navid Emamdoost wrote:
On Sat, Oct 12, 2019 at 4:07 AM Markus Elfring Markus.Elfring@web.de wrote:
From: Markus Elfring elfring@users.sourceforge.net Date: Sat, 12 Oct 2019 10:30:21 +0200
The return value from a call of the function “kmemdup” was not checked in this function implementation. Thus add the corresponding error handling.
Fixes: 19022aaae677dfa171a719e9d1ff04823ce65a65 ("staging: drm/imx: Add parallel display support") Signed-off-by: Markus Elfring elfring@users.sourceforge.net
drivers/gpu/drm/imx/parallel-display.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c index 35518e5de356..39c4798f56b6 100644 --- a/drivers/gpu/drm/imx/parallel-display.c +++ b/drivers/gpu/drm/imx/parallel-display.c @@ -210,8 +210,13 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data) return -ENOMEM;
edidp = of_get_property(np, "edid", &imxpd->edid_len);
if (edidp)
if (edidp) { imxpd->edid = kmemdup(edidp, imxpd->edid_len, GFP_KERNEL);if (!imxpd->edid) {devm_kfree(dev, imxpd);You should not try to free imxpd here as it is a resource-managed allocation via devm_kzalloc(). It means memory allocated with this function is automatically freed on driver detach. So, this patch introduces a double-free.
No, it's not double freed since the proposed code frees it with a devm function, removing it from the list of things to free later. One can wonder why the free has to be made apparent, though.
julia
return -ENOMEM;}} ret = of_property_read_string(np, "interface-pix-fmt", &fmt); if (!ret) {-- 2.23.0
-- Navid.
From: Markus Elfring elfring@users.sourceforge.net Date: Sat, 12 Oct 2019 10:33:47 +0200
The return value from a call of the function “kmemdup” was not checked in this function implementation. Thus add the corresponding error handling.
This issue was detected by using the Coccinelle software.
Fixes: dc80d7038883feca2abd08975165bc0d83c84762 ("drm/imx-ldb: Add support to drm-bridge") Signed-off-by: Markus Elfring elfring@users.sourceforge.net --- drivers/gpu/drm/imx/imx-ldb.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c index 208069faf183..801a2265dd11 100644 --- a/drivers/gpu/drm/imx/imx-ldb.c +++ b/drivers/gpu/drm/imx/imx-ldb.c @@ -569,6 +569,8 @@ static int imx_ldb_panel_ddc(struct device *dev, channel->edid = kmemdup(edidp, channel->edid_len, GFP_KERNEL); + if (!channel->edid) + return -ENOMEM; } else if (!channel->panel) { /* fallback to display-timings node */ ret = of_get_drm_display_mode(child, -- 2.23.0
On Fri, Oct 4, 2019 at 2:09 PM Navid Emamdoost navid.emamdoost@gmail.com wrote:
In imx_pd_bind, the duplicated memory for imxpd->edid via kmemdup should be released in drm_of_find_panel_or_bridge or imx_pd_register fail.
Fixes: ebc944613567 ("drm: convert drivers to use drm_of_find_panel_or_bridge") Fixes: 19022aaae677 ("staging: drm/imx: Add parallel display support") Signed-off-by: Navid Emamdoost navid.emamdoost@gmail.com
Would you please review this patch?
Thanks,
drivers/gpu/drm/imx/parallel-display.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c index e7ce17503ae1..9522d2cb0ad5 100644 --- a/drivers/gpu/drm/imx/parallel-display.c +++ b/drivers/gpu/drm/imx/parallel-display.c @@ -227,14 +227,18 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data)
/* port@1 is the output port */ ret = drm_of_find_panel_or_bridge(np, 1, 0, &imxpd->panel, &imxpd->bridge);
if (ret && ret != -ENODEV)
if (ret && ret != -ENODEV) {kfree(imxpd->edid); return ret;} imxpd->dev = dev; ret = imx_pd_register(drm, imxpd);
if (ret)
if (ret) {kfree(imxpd->edid); return ret;} dev_set_drvdata(dev, imxpd);-- 2.17.1
Hi Navid,
On 19-11-21 12:31, Navid Emamdoost wrote:
On Fri, Oct 4, 2019 at 2:09 PM Navid Emamdoost navid.emamdoost@gmail.com wrote:
In imx_pd_bind, the duplicated memory for imxpd->edid via kmemdup should be released in drm_of_find_panel_or_bridge or imx_pd_register fail.
Fixes: ebc944613567 ("drm: convert drivers to use drm_of_find_panel_or_bridge") Fixes: 19022aaae677 ("staging: drm/imx: Add parallel display support") Signed-off-by: Navid Emamdoost navid.emamdoost@gmail.com
Would you please review this patch?
Thanks,
I currently work on the drm/imx driver(s) to avoid errors like [1]. Hopefully I have a working version till next week. There I fixed this issue by using the devm_kmemdup() and dropped the explicit kfree() within unbind().
[1] https://www.spinics.net/lists/dri-devel/msg189388.html
Regards, Marco
drivers/gpu/drm/imx/parallel-display.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c index e7ce17503ae1..9522d2cb0ad5 100644 --- a/drivers/gpu/drm/imx/parallel-display.c +++ b/drivers/gpu/drm/imx/parallel-display.c @@ -227,14 +227,18 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data)
/* port@1 is the output port */ ret = drm_of_find_panel_or_bridge(np, 1, 0, &imxpd->panel, &imxpd->bridge);
if (ret && ret != -ENODEV)
if (ret && ret != -ENODEV) {kfree(imxpd->edid); return ret;} imxpd->dev = dev; ret = imx_pd_register(drm, imxpd);
if (ret)
if (ret) {kfree(imxpd->edid); return ret;} dev_set_drvdata(dev, imxpd);-- 2.17.1
-- Navid.
Thanks for the update.
On Fri, Nov 22, 2019 at 1:22 AM Marco Felsch m.felsch@pengutronix.de wrote:
Hi Navid,
On 19-11-21 12:31, Navid Emamdoost wrote:
On Fri, Oct 4, 2019 at 2:09 PM Navid Emamdoost navid.emamdoost@gmail.com wrote:
In imx_pd_bind, the duplicated memory for imxpd->edid via kmemdup should be released in drm_of_find_panel_or_bridge or imx_pd_register fail.
Fixes: ebc944613567 ("drm: convert drivers to use drm_of_find_panel_or_bridge") Fixes: 19022aaae677 ("staging: drm/imx: Add parallel display support") Signed-off-by: Navid Emamdoost navid.emamdoost@gmail.com
Would you please review this patch?
Thanks,
I currently work on the drm/imx driver(s) to avoid errors like [1]. Hopefully I have a working version till next week. There I fixed this issue by using the devm_kmemdup() and dropped the explicit kfree() within unbind().
[1] https://www.spinics.net/lists/dri-devel/msg189388.html
Regards, Marco
drivers/gpu/drm/imx/parallel-display.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c index e7ce17503ae1..9522d2cb0ad5 100644 --- a/drivers/gpu/drm/imx/parallel-display.c +++ b/drivers/gpu/drm/imx/parallel-display.c @@ -227,14 +227,18 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data)
/* port@1 is the output port */ ret = drm_of_find_panel_or_bridge(np, 1, 0, &imxpd->panel, &imxpd->bridge);
if (ret && ret != -ENODEV)
if (ret && ret != -ENODEV) {kfree(imxpd->edid); return ret;} imxpd->dev = dev; ret = imx_pd_register(drm, imxpd);
if (ret)
if (ret) {kfree(imxpd->edid); return ret;} dev_set_drvdata(dev, imxpd);-- 2.17.1
-- Navid.
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