* [PATCH] firmware: arm_scpi: Ensure scpi_info is not assigned if the probe fails
@ 2022-07-01 16:03 Sudeep Holla
2022-07-04 1:19 ` Jackie Liu
2022-07-06 9:39 ` Sudeep Holla
0 siblings, 2 replies; 4+ messages in thread
From: Sudeep Holla @ 2022-07-01 16:03 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Sudeep Holla, luriwen, liuyun01, 15815827059, cristian.marussi,
huhai, stable
When scpi probe fails, at any point, we need to ensure that the scpi_info
is not set and will remain NULL until the probe succeeds. If it is not
taken care, then it could result in kernel panic with a NULL pointer
dereference.
Reported-by: huhai <huhai@kylinos.cn>
Cc: stable@vger.kernel.org # 4.19+
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
drivers/firmware/arm_scpi.c | 57 +++++++++++++++++++++----------------
1 file changed, 32 insertions(+), 25 deletions(-)
diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c
index ddf0b9ff9e15..085a71a00171 100644
--- a/drivers/firmware/arm_scpi.c
+++ b/drivers/firmware/arm_scpi.c
@@ -913,13 +913,14 @@ static int scpi_probe(struct platform_device *pdev)
struct resource res;
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
+ struct scpi_drvinfo *scpi_drvinfo;
- scpi_info = devm_kzalloc(dev, sizeof(*scpi_info), GFP_KERNEL);
- if (!scpi_info)
+ scpi_drvinfo = devm_kzalloc(dev, sizeof(*scpi_drvinfo), GFP_KERNEL);
+ if (!scpi_drvinfo)
return -ENOMEM;
if (of_match_device(legacy_scpi_of_match, &pdev->dev))
- scpi_info->is_legacy = true;
+ scpi_drvinfo->is_legacy = true;
count = of_count_phandle_with_args(np, "mboxes", "#mbox-cells");
if (count < 0) {
@@ -927,19 +928,19 @@ static int scpi_probe(struct platform_device *pdev)
return -ENODEV;
}
- scpi_info->channels = devm_kcalloc(dev, count, sizeof(struct scpi_chan),
- GFP_KERNEL);
- if (!scpi_info->channels)
+ scpi_drvinfo->channels =
+ devm_kcalloc(dev, count, sizeof(struct scpi_chan), GFP_KERNEL);
+ if (!scpi_drvinfo->channels)
return -ENOMEM;
- ret = devm_add_action(dev, scpi_free_channels, scpi_info);
+ ret = devm_add_action(dev, scpi_free_channels, scpi_drvinfo);
if (ret)
return ret;
- for (; scpi_info->num_chans < count; scpi_info->num_chans++) {
+ for (; scpi_drvinfo->num_chans < count; scpi_drvinfo->num_chans++) {
resource_size_t size;
- int idx = scpi_info->num_chans;
- struct scpi_chan *pchan = scpi_info->channels + idx;
+ int idx = scpi_drvinfo->num_chans;
+ struct scpi_chan *pchan = scpi_drvinfo->channels + idx;
struct mbox_client *cl = &pchan->cl;
struct device_node *shmem = of_parse_phandle(np, "shmem", idx);
@@ -986,45 +987,51 @@ static int scpi_probe(struct platform_device *pdev)
return ret;
}
- scpi_info->commands = scpi_std_commands;
+ scpi_drvinfo->commands = scpi_std_commands;
- platform_set_drvdata(pdev, scpi_info);
+ platform_set_drvdata(pdev, scpi_drvinfo);
- if (scpi_info->is_legacy) {
+ if (scpi_drvinfo->is_legacy) {
/* Replace with legacy variants */
scpi_ops.clk_set_val = legacy_scpi_clk_set_val;
- scpi_info->commands = scpi_legacy_commands;
+ scpi_drvinfo->commands = scpi_legacy_commands;
/* Fill priority bitmap */
for (idx = 0; idx < ARRAY_SIZE(legacy_hpriority_cmds); idx++)
set_bit(legacy_hpriority_cmds[idx],
- scpi_info->cmd_priority);
+ scpi_drvinfo->cmd_priority);
}
- ret = scpi_init_versions(scpi_info);
+ ret = scpi_init_versions(scpi_drvinfo);
if (ret) {
dev_err(dev, "incorrect or no SCP firmware found\n");
return ret;
}
- if (scpi_info->is_legacy && !scpi_info->protocol_version &&
- !scpi_info->firmware_version)
+ if (scpi_drvinfo->is_legacy && !scpi_drvinfo->protocol_version &&
+ !scpi_drvinfo->firmware_version)
dev_info(dev, "SCP Protocol legacy pre-1.0 firmware\n");
else
dev_info(dev, "SCP Protocol %lu.%lu Firmware %lu.%lu.%lu version\n",
FIELD_GET(PROTO_REV_MAJOR_MASK,
- scpi_info->protocol_version),
+ scpi_drvinfo->protocol_version),
FIELD_GET(PROTO_REV_MINOR_MASK,
- scpi_info->protocol_version),
+ scpi_drvinfo->protocol_version),
FIELD_GET(FW_REV_MAJOR_MASK,
- scpi_info->firmware_version),
+ scpi_drvinfo->firmware_version),
FIELD_GET(FW_REV_MINOR_MASK,
- scpi_info->firmware_version),
+ scpi_drvinfo->firmware_version),
FIELD_GET(FW_REV_PATCH_MASK,
- scpi_info->firmware_version));
- scpi_info->scpi_ops = &scpi_ops;
+ scpi_drvinfo->firmware_version));
+
+ scpi_drvinfo->scpi_ops = &scpi_ops;
+
+ ret = devm_of_platform_populate(dev);
- return devm_of_platform_populate(dev);
+ if (!ret)
+ scpi_info = scpi_drvinfo;
+
+ return ret;
}
static const struct of_device_id scpi_of_match[] = {
--
2.37.0
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] firmware: arm_scpi: Ensure scpi_info is not assigned if the probe fails
2022-07-01 16:03 [PATCH] firmware: arm_scpi: Ensure scpi_info is not assigned if the probe fails Sudeep Holla
@ 2022-07-04 1:19 ` Jackie Liu
2022-07-04 9:22 ` Sudeep Holla
2022-07-06 9:39 ` Sudeep Holla
1 sibling, 1 reply; 4+ messages in thread
From: Jackie Liu @ 2022-07-04 1:19 UTC (permalink / raw)
To: Sudeep Holla, linux-arm-kernel
Cc: luriwen, 15815827059, cristian.marussi, huhai, stable
Hi Sudeep.
Thanks for your patch, It's look good to me.
Reviewed-by: Jackie Liu <liuyun01@kylinos.cn>
在 2022/7/2 00:03, Sudeep Holla 写道:
> When scpi probe fails, at any point, we need to ensure that the scpi_info
> is not set and will remain NULL until the probe succeeds. If it is not
> taken care, then it could result in kernel panic with a NULL pointer
> dereference.
I think the null pointer reference is not correct. It should be UAF. The
logic is as follows:
scpi_info = devm_zalloc
After that if fails, the address will be released, but scpi_info is not
NULL. Normal, there will be no problem, because scpi_info is alloc by
kzalloc, so even if scpi_info is not NULL, but scpi_info->scpi_ops is
NULL, It still work normally.
But if another process or thread alloc a new data, if they are same
address, and then it is assigned a value, so wild pointer
scpi_info->scpi_ops is not NULL now, Then, Panic.
Thanks.
--
Jackie Liu.
>
> Reported-by: huhai <huhai@kylinos.cn>
> Cc: stable@vger.kernel.org # 4.19+
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> ---
> drivers/firmware/arm_scpi.c | 57 +++++++++++++++++++++----------------
> 1 file changed, 32 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c
> index ddf0b9ff9e15..085a71a00171 100644
> --- a/drivers/firmware/arm_scpi.c
> +++ b/drivers/firmware/arm_scpi.c
> @@ -913,13 +913,14 @@ static int scpi_probe(struct platform_device *pdev)
> struct resource res;
> struct device *dev = &pdev->dev;
> struct device_node *np = dev->of_node;
> + struct scpi_drvinfo *scpi_drvinfo;
>
> - scpi_info = devm_kzalloc(dev, sizeof(*scpi_info), GFP_KERNEL);
> - if (!scpi_info)
> + scpi_drvinfo = devm_kzalloc(dev, sizeof(*scpi_drvinfo), GFP_KERNEL);
> + if (!scpi_drvinfo)
> return -ENOMEM;
>
> if (of_match_device(legacy_scpi_of_match, &pdev->dev))
> - scpi_info->is_legacy = true;
> + scpi_drvinfo->is_legacy = true;
>
> count = of_count_phandle_with_args(np, "mboxes", "#mbox-cells");
> if (count < 0) {
> @@ -927,19 +928,19 @@ static int scpi_probe(struct platform_device *pdev)
> return -ENODEV;
> }
>
> - scpi_info->channels = devm_kcalloc(dev, count, sizeof(struct scpi_chan),
> - GFP_KERNEL);
> - if (!scpi_info->channels)
> + scpi_drvinfo->channels =
> + devm_kcalloc(dev, count, sizeof(struct scpi_chan), GFP_KERNEL);
> + if (!scpi_drvinfo->channels)
> return -ENOMEM;
>
> - ret = devm_add_action(dev, scpi_free_channels, scpi_info);
> + ret = devm_add_action(dev, scpi_free_channels, scpi_drvinfo);
> if (ret)
> return ret;
>
> - for (; scpi_info->num_chans < count; scpi_info->num_chans++) {
> + for (; scpi_drvinfo->num_chans < count; scpi_drvinfo->num_chans++) {
> resource_size_t size;
> - int idx = scpi_info->num_chans;
> - struct scpi_chan *pchan = scpi_info->channels + idx;
> + int idx = scpi_drvinfo->num_chans;
> + struct scpi_chan *pchan = scpi_drvinfo->channels + idx;
> struct mbox_client *cl = &pchan->cl;
> struct device_node *shmem = of_parse_phandle(np, "shmem", idx);
>
> @@ -986,45 +987,51 @@ static int scpi_probe(struct platform_device *pdev)
> return ret;
> }
>
> - scpi_info->commands = scpi_std_commands;
> + scpi_drvinfo->commands = scpi_std_commands;
>
> - platform_set_drvdata(pdev, scpi_info);
> + platform_set_drvdata(pdev, scpi_drvinfo);
>
> - if (scpi_info->is_legacy) {
> + if (scpi_drvinfo->is_legacy) {
> /* Replace with legacy variants */
> scpi_ops.clk_set_val = legacy_scpi_clk_set_val;
> - scpi_info->commands = scpi_legacy_commands;
> + scpi_drvinfo->commands = scpi_legacy_commands;
>
> /* Fill priority bitmap */
> for (idx = 0; idx < ARRAY_SIZE(legacy_hpriority_cmds); idx++)
> set_bit(legacy_hpriority_cmds[idx],
> - scpi_info->cmd_priority);
> + scpi_drvinfo->cmd_priority);
> }
>
> - ret = scpi_init_versions(scpi_info);
> + ret = scpi_init_versions(scpi_drvinfo);
> if (ret) {
> dev_err(dev, "incorrect or no SCP firmware found\n");
> return ret;
> }
>
> - if (scpi_info->is_legacy && !scpi_info->protocol_version &&
> - !scpi_info->firmware_version)
> + if (scpi_drvinfo->is_legacy && !scpi_drvinfo->protocol_version &&
> + !scpi_drvinfo->firmware_version)
> dev_info(dev, "SCP Protocol legacy pre-1.0 firmware\n");
> else
> dev_info(dev, "SCP Protocol %lu.%lu Firmware %lu.%lu.%lu version\n",
> FIELD_GET(PROTO_REV_MAJOR_MASK,
> - scpi_info->protocol_version),
> + scpi_drvinfo->protocol_version),
> FIELD_GET(PROTO_REV_MINOR_MASK,
> - scpi_info->protocol_version),
> + scpi_drvinfo->protocol_version),
> FIELD_GET(FW_REV_MAJOR_MASK,
> - scpi_info->firmware_version),
> + scpi_drvinfo->firmware_version),
> FIELD_GET(FW_REV_MINOR_MASK,
> - scpi_info->firmware_version),
> + scpi_drvinfo->firmware_version),
> FIELD_GET(FW_REV_PATCH_MASK,
> - scpi_info->firmware_version));
> - scpi_info->scpi_ops = &scpi_ops;
> + scpi_drvinfo->firmware_version));
> +
> + scpi_drvinfo->scpi_ops = &scpi_ops;
> +
> + ret = devm_of_platform_populate(dev);
>
> - return devm_of_platform_populate(dev);
> + if (!ret)
> + scpi_info = scpi_drvinfo;
> +
> + return ret;
> }
>
> static const struct of_device_id scpi_of_match[] = {
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] firmware: arm_scpi: Ensure scpi_info is not assigned if the probe fails
2022-07-04 1:19 ` Jackie Liu
@ 2022-07-04 9:22 ` Sudeep Holla
0 siblings, 0 replies; 4+ messages in thread
From: Sudeep Holla @ 2022-07-04 9:22 UTC (permalink / raw)
To: Jackie Liu
Cc: linux-arm-kernel, luriwen, 15815827059, cristian.marussi, huhai, stable
On Mon, Jul 04, 2022 at 09:19:56AM +0800, Jackie Liu wrote:
> Hi Sudeep.
>
> Thanks for your patch, It's look good to me.
>
> Reviewed-by: Jackie Liu <liuyun01@kylinos.cn>
>
> 在 2022/7/2 00:03, Sudeep Holla 写道:
> > When scpi probe fails, at any point, we need to ensure that the scpi_info
> > is not set and will remain NULL until the probe succeeds. If it is not
> > taken care, then it could result in kernel panic with a NULL pointer
> > dereference.
>
> I think the null pointer reference is not correct. It should be UAF. The
> logic is as follows:
>
Right, I will update the commit message, sorry for that got carried away by
the message in the kernel panic.
> scpi_info = devm_zalloc
>
> After that if fails, the address will be released, but scpi_info is not
> NULL. Normal, there will be no problem, because scpi_info is alloc by
> kzalloc, so even if scpi_info is not NULL, but scpi_info->scpi_ops is
> NULL, It still work normally.
>
> But if another process or thread alloc a new data, if they are same address,
> and then it is assigned a value, so wild pointer scpi_info->scpi_ops is not
> NULL now, Then, Panic.
>
I do understand that, I will update the commit log to cover these and
thanks for the review.
--
Regards,
Sudeep
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] firmware: arm_scpi: Ensure scpi_info is not assigned if the probe fails
2022-07-01 16:03 [PATCH] firmware: arm_scpi: Ensure scpi_info is not assigned if the probe fails Sudeep Holla
2022-07-04 1:19 ` Jackie Liu
@ 2022-07-06 9:39 ` Sudeep Holla
1 sibling, 0 replies; 4+ messages in thread
From: Sudeep Holla @ 2022-07-06 9:39 UTC (permalink / raw)
To: linux-arm-kernel, Sudeep Holla
Cc: huhai, luriwen, liuyun01, cristian.marussi, 15815827059, stable
On Fri, 1 Jul 2022 17:03:10 +0100, Sudeep Holla wrote:
> When scpi probe fails, at any point, we need to ensure that the scpi_info
> is not set and will remain NULL until the probe succeeds. If it is not
> taken care, then it could result in kernel panic with a NULL pointer
> dereference.
>
>
Applied to sudeep.holla/linux (for-next/scmi), thanks!
[1/1] firmware: arm_scpi: Ensure scpi_info is not assigned if the probe fails
https://git.kernel.org/sudeep.holla/c/689640efc0
--
Regards,
Sudeep
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2022-07-01 16:03 [PATCH] firmware: arm_scpi: Ensure scpi_info is not assigned if the probe fails Sudeep Holla
2022-07-04 1:19 ` Jackie Liu
2022-07-04 9:22 ` Sudeep Holla
2022-07-06 9:39 ` Sudeep Holla
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