Re: [PATCH v2 09/11] firmware: enable to force disable the fallback mechanism at run time

[Kees Cook]

On Fri, Feb 23, 2018 at 6:46 PM, Luis R. Rodriguez  wrote:
> You currently need four different kernel builds to test the firmware
> API fully. By adding a proc knob to force disable the fallback mechanism
> completely we are able to reduce the amount of kernels you need built
> to test the firmware API down to two.
>
> Signed-off-by: Luis R. Rodriguez 

Acked-by: Kees Cook 

-Kees

> ---
>  drivers/base/firmware_fallback.c   | 5 +
>  drivers/base/firmware_fallback.h   | 4 
>  drivers/base/firmware_fallback_table.c | 9 +
>  3 files changed, 18 insertions(+)
>
> diff --git a/drivers/base/firmware_fallback.c 
> b/drivers/base/firmware_fallback.c
> index cbce9a950cd8..13fa5ff2b46c 100644
> --- a/drivers/base/firmware_fallback.c
> +++ b/drivers/base/firmware_fallback.c
> @@ -643,6 +643,11 @@ static bool fw_force_sysfs_fallback(unsigned int 
> opt_flags)
>
>  static bool fw_run_sysfs_fallback(unsigned int opt_flags)
>  {
> +   if (fw_fallback_config.ignore_sysfs_fallback) {
> +   pr_info_once("Ignoring firmware sysfs fallback due to debugfs 
> knob\n");
> +   return false;
> +   }
> +
> if ((opt_flags & FW_OPT_NOFALLBACK))
> return false;
>
> diff --git a/drivers/base/firmware_fallback.h 
> b/drivers/base/firmware_fallback.h
> index ca7e69a8417b..dfebc644ed35 100644
> --- a/drivers/base/firmware_fallback.h
> +++ b/drivers/base/firmware_fallback.h
> @@ -14,12 +14,16 @@
>   * as if one had enabled CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y.
>   * Useful to help debug a CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
>   * functionality on a kernel where that config entry has been disabled.
> + * @ignore_sysfs_fallback: force to disable the sysfs fallback mechanism.
> + * This emulates the behaviour as if we had set the kernel
> + * config CONFIG_FW_LOADER_USER_HELPER=n.
>   * @old_timeout: for internal use
>   * @loading_timeout: the timeout to wait for the fallback mechanism before
>   * giving up, in seconds.
>   */
>  struct firmware_fallback_config {
> unsigned int force_sysfs_fallback;
> +   unsigned int ignore_sysfs_fallback;
> int old_timeout;
> int loading_timeout;
>  };
> diff --git a/drivers/base/firmware_fallback_table.c 
> b/drivers/base/firmware_fallback_table.c
> index 77300d5e9c52..5e990b0330c7 100644
> --- a/drivers/base/firmware_fallback_table.c
> +++ b/drivers/base/firmware_fallback_table.c
> @@ -39,6 +39,15 @@ struct ctl_table firmware_config_table[] = {
> .extra1 = ,
> .extra2 = ,
> },
> +   {
> +   .procname   = "ignore_sysfs_fallback",
> +   .data   = _fallback_config.ignore_sysfs_fallback,
> +   .maxlen = sizeof(unsigned int),
> +   .mode   = 0644,
> +   .proc_handler   = proc_douintvec_minmax,
> +   .extra1 = ,
> +   .extra2 = ,
> +   },
> { }
>  };
>  EXPORT_SYMBOL_GPL(firmware_config_table);
> --
> 2.16.2
>



-- 
Kees Cook
Pixel Security

Re: [PATCH v2 09/11] firmware: enable to force disable the fallback mechanism at run time

[Kees Cook]

On Fri, Feb 23, 2018 at 6:46 PM, Luis R. Rodriguez  wrote:
> You currently need four different kernel builds to test the firmware
> API fully. By adding a proc knob to force disable the fallback mechanism
> completely we are able to reduce the amount of kernels you need built
> to test the firmware API down to two.
>
> Signed-off-by: Luis R. Rodriguez 

Acked-by: Kees Cook 

-Kees

> ---
>  drivers/base/firmware_fallback.c   | 5 +
>  drivers/base/firmware_fallback.h   | 4 
>  drivers/base/firmware_fallback_table.c | 9 +
>  3 files changed, 18 insertions(+)
>
> diff --git a/drivers/base/firmware_fallback.c 
> b/drivers/base/firmware_fallback.c
> index cbce9a950cd8..13fa5ff2b46c 100644
> --- a/drivers/base/firmware_fallback.c
> +++ b/drivers/base/firmware_fallback.c
> @@ -643,6 +643,11 @@ static bool fw_force_sysfs_fallback(unsigned int 
> opt_flags)
>
>  static bool fw_run_sysfs_fallback(unsigned int opt_flags)
>  {
> +   if (fw_fallback_config.ignore_sysfs_fallback) {
> +   pr_info_once("Ignoring firmware sysfs fallback due to debugfs 
> knob\n");
> +   return false;
> +   }
> +
> if ((opt_flags & FW_OPT_NOFALLBACK))
> return false;
>
> diff --git a/drivers/base/firmware_fallback.h 
> b/drivers/base/firmware_fallback.h
> index ca7e69a8417b..dfebc644ed35 100644
> --- a/drivers/base/firmware_fallback.h
> +++ b/drivers/base/firmware_fallback.h
> @@ -14,12 +14,16 @@
>   * as if one had enabled CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y.
>   * Useful to help debug a CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
>   * functionality on a kernel where that config entry has been disabled.
> + * @ignore_sysfs_fallback: force to disable the sysfs fallback mechanism.
> + * This emulates the behaviour as if we had set the kernel
> + * config CONFIG_FW_LOADER_USER_HELPER=n.
>   * @old_timeout: for internal use
>   * @loading_timeout: the timeout to wait for the fallback mechanism before
>   * giving up, in seconds.
>   */
>  struct firmware_fallback_config {
> unsigned int force_sysfs_fallback;
> +   unsigned int ignore_sysfs_fallback;
> int old_timeout;
> int loading_timeout;
>  };
> diff --git a/drivers/base/firmware_fallback_table.c 
> b/drivers/base/firmware_fallback_table.c
> index 77300d5e9c52..5e990b0330c7 100644
> --- a/drivers/base/firmware_fallback_table.c
> +++ b/drivers/base/firmware_fallback_table.c
> @@ -39,6 +39,15 @@ struct ctl_table firmware_config_table[] = {
> .extra1 = ,
> .extra2 = ,
> },
> +   {
> +   .procname   = "ignore_sysfs_fallback",
> +   .data   = _fallback_config.ignore_sysfs_fallback,
> +   .maxlen = sizeof(unsigned int),
> +   .mode   = 0644,
> +   .proc_handler   = proc_douintvec_minmax,
> +   .extra1 = ,
> +   .extra2 = ,
> +   },
> { }
>  };
>  EXPORT_SYMBOL_GPL(firmware_config_table);
> --
> 2.16.2
>



-- 
Kees Cook
Pixel Security

[PATCH v2 09/11] firmware: enable to force disable the fallback mechanism at run time

[Luis R. Rodriguez]

You currently need four different kernel builds to test the firmware
API fully. By adding a proc knob to force disable the fallback mechanism
completely we are able to reduce the amount of kernels you need built
to test the firmware API down to two.

Signed-off-by: Luis R. Rodriguez 
---
 drivers/base/firmware_fallback.c   | 5 +
 drivers/base/firmware_fallback.h   | 4 
 drivers/base/firmware_fallback_table.c | 9 +
 3 files changed, 18 insertions(+)

diff --git a/drivers/base/firmware_fallback.c b/drivers/base/firmware_fallback.c
index cbce9a950cd8..13fa5ff2b46c 100644
--- a/drivers/base/firmware_fallback.c
+++ b/drivers/base/firmware_fallback.c
@@ -643,6 +643,11 @@ static bool fw_force_sysfs_fallback(unsigned int opt_flags)
 
 static bool fw_run_sysfs_fallback(unsigned int opt_flags)
 {
+   if (fw_fallback_config.ignore_sysfs_fallback) {
+   pr_info_once("Ignoring firmware sysfs fallback due to debugfs 
knob\n");
+   return false;
+   }
+
if ((opt_flags & FW_OPT_NOFALLBACK))
return false;
 
diff --git a/drivers/base/firmware_fallback.h b/drivers/base/firmware_fallback.h
index ca7e69a8417b..dfebc644ed35 100644
--- a/drivers/base/firmware_fallback.h
+++ b/drivers/base/firmware_fallback.h
@@ -14,12 +14,16 @@
  * as if one had enabled CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y.
  * Useful to help debug a CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
  * functionality on a kernel where that config entry has been disabled.
+ * @ignore_sysfs_fallback: force to disable the sysfs fallback mechanism.
+ * This emulates the behaviour as if we had set the kernel
+ * config CONFIG_FW_LOADER_USER_HELPER=n.
  * @old_timeout: for internal use
  * @loading_timeout: the timeout to wait for the fallback mechanism before
  * giving up, in seconds.
  */
 struct firmware_fallback_config {
unsigned int force_sysfs_fallback;
+   unsigned int ignore_sysfs_fallback;
int old_timeout;
int loading_timeout;
 };
diff --git a/drivers/base/firmware_fallback_table.c 
b/drivers/base/firmware_fallback_table.c
index 77300d5e9c52..5e990b0330c7 100644
--- a/drivers/base/firmware_fallback_table.c
+++ b/drivers/base/firmware_fallback_table.c
@@ -39,6 +39,15 @@ struct ctl_table firmware_config_table[] = {
.extra1 = ,
.extra2 = ,
},
+   {
+   .procname   = "ignore_sysfs_fallback",
+   .data   = _fallback_config.ignore_sysfs_fallback,
+   .maxlen = sizeof(unsigned int),
+   .mode   = 0644,
+   .proc_handler   = proc_douintvec_minmax,
+   .extra1 = ,
+   .extra2 = ,
+   },
{ }
 };
 EXPORT_SYMBOL_GPL(firmware_config_table);
-- 
2.16.2

[PATCH v2 09/11] firmware: enable to force disable the fallback mechanism at run time

[Luis R. Rodriguez]

You currently need four different kernel builds to test the firmware
API fully. By adding a proc knob to force disable the fallback mechanism
completely we are able to reduce the amount of kernels you need built
to test the firmware API down to two.

Signed-off-by: Luis R. Rodriguez 
---
 drivers/base/firmware_fallback.c   | 5 +
 drivers/base/firmware_fallback.h   | 4 
 drivers/base/firmware_fallback_table.c | 9 +
 3 files changed, 18 insertions(+)

diff --git a/drivers/base/firmware_fallback.c b/drivers/base/firmware_fallback.c
index cbce9a950cd8..13fa5ff2b46c 100644
--- a/drivers/base/firmware_fallback.c
+++ b/drivers/base/firmware_fallback.c
@@ -643,6 +643,11 @@ static bool fw_force_sysfs_fallback(unsigned int opt_flags)
 
 static bool fw_run_sysfs_fallback(unsigned int opt_flags)
 {
+   if (fw_fallback_config.ignore_sysfs_fallback) {
+   pr_info_once("Ignoring firmware sysfs fallback due to debugfs 
knob\n");
+   return false;
+   }
+
if ((opt_flags & FW_OPT_NOFALLBACK))
return false;
 
diff --git a/drivers/base/firmware_fallback.h b/drivers/base/firmware_fallback.h
index ca7e69a8417b..dfebc644ed35 100644
--- a/drivers/base/firmware_fallback.h
+++ b/drivers/base/firmware_fallback.h
@@ -14,12 +14,16 @@
  * as if one had enabled CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y.
  * Useful to help debug a CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
  * functionality on a kernel where that config entry has been disabled.
+ * @ignore_sysfs_fallback: force to disable the sysfs fallback mechanism.
+ * This emulates the behaviour as if we had set the kernel
+ * config CONFIG_FW_LOADER_USER_HELPER=n.
  * @old_timeout: for internal use
  * @loading_timeout: the timeout to wait for the fallback mechanism before
  * giving up, in seconds.
  */
 struct firmware_fallback_config {
unsigned int force_sysfs_fallback;
+   unsigned int ignore_sysfs_fallback;
int old_timeout;
int loading_timeout;
 };
diff --git a/drivers/base/firmware_fallback_table.c 
b/drivers/base/firmware_fallback_table.c
index 77300d5e9c52..5e990b0330c7 100644
--- a/drivers/base/firmware_fallback_table.c
+++ b/drivers/base/firmware_fallback_table.c
@@ -39,6 +39,15 @@ struct ctl_table firmware_config_table[] = {
.extra1 = ,
.extra2 = ,
},
+   {
+   .procname   = "ignore_sysfs_fallback",
+   .data   = _fallback_config.ignore_sysfs_fallback,
+   .maxlen = sizeof(unsigned int),
+   .mode   = 0644,
+   .proc_handler   = proc_douintvec_minmax,
+   .extra1 = ,
+   .extra2 = ,
+   },
{ }
 };
 EXPORT_SYMBOL_GPL(firmware_config_table);
-- 
2.16.2

[PATCH v2 09/11] firmware: enable to force disable the fallback mechanism at run time

[Luis R. Rodriguez]

You currently need four different kernel builds to test the firmware
API fully. By adding a proc knob to force disable the fallback mechanism
completely we are able to reduce the amount of kernels you need built
to test the firmware API down to two.

Signed-off-by: Luis R. Rodriguez 
---
 drivers/base/firmware_fallback.c | 18 ++
 1 file changed, 18 insertions(+)

diff --git a/drivers/base/firmware_fallback.c b/drivers/base/firmware_fallback.c
index 1a5bb3d22417..bf63034e0556 100644
--- a/drivers/base/firmware_fallback.c
+++ b/drivers/base/firmware_fallback.c
@@ -28,12 +28,16 @@ static unsigned int one = 1;
  * as if one had enabled CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y.
  * Useful to help debug a CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
  * functionality on a kernel where that config entry has been disabled.
+ * @ignore_sysfs_fallback: force to disable the sysfs fallback mechanism.
+ * This emulates the behaviour as if we had set the kernel
+ * config CONFIG_FW_LOADER_USER_HELPER=n.
  * @old_timeout: for internal use
  * @loading_timeout: the timeout to wait for the fallback mechanism before
  * giving up, in seconds.
  */
 struct firmware_fallback_config {
unsigned int force_sysfs_fallback;
+   unsigned int ignore_sysfs_fallback;
int old_timeout;
int loading_timeout;
 };
@@ -54,6 +58,15 @@ struct ctl_table firmware_config_table[] = {
.extra1 = ,
.extra2 = ,
},
+   {
+   .procname   = "ignore_sysfs_fallback",
+   .data   = _fallback_config.ignore_sysfs_fallback,
+   .maxlen = sizeof(unsigned int),
+   .mode   = 0644,
+   .proc_handler   = proc_douintvec_minmax,
+   .extra1 = ,
+   .extra2 = ,
+   },
{ }
 };
 EXPORT_SYMBOL_GPL(firmware_config_table);
@@ -683,6 +696,11 @@ static bool fw_force_sysfs_fallback(unsigned int opt_flags)
 
 static bool fw_run_sysfs_fallback(unsigned int opt_flags)
 {
+   if (fw_fallback_config.ignore_sysfs_fallback) {
+   pr_info_once("Ignoring firmware sysfs fallback due to debugfs 
knob\n");
+   return false;
+   }
+
if ((opt_flags & FW_OPT_NOFALLBACK))
return false;
 
-- 
2.16.1

[PATCH v2 09/11] firmware: enable to force disable the fallback mechanism at run time

[Luis R. Rodriguez]

You currently need four different kernel builds to test the firmware
API fully. By adding a proc knob to force disable the fallback mechanism
completely we are able to reduce the amount of kernels you need built
to test the firmware API down to two.

Signed-off-by: Luis R. Rodriguez 
---
 drivers/base/firmware_fallback.c | 18 ++
 1 file changed, 18 insertions(+)

diff --git a/drivers/base/firmware_fallback.c b/drivers/base/firmware_fallback.c
index 1a5bb3d22417..bf63034e0556 100644
--- a/drivers/base/firmware_fallback.c
+++ b/drivers/base/firmware_fallback.c
@@ -28,12 +28,16 @@ static unsigned int one = 1;
  * as if one had enabled CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y.
  * Useful to help debug a CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
  * functionality on a kernel where that config entry has been disabled.
+ * @ignore_sysfs_fallback: force to disable the sysfs fallback mechanism.
+ * This emulates the behaviour as if we had set the kernel
+ * config CONFIG_FW_LOADER_USER_HELPER=n.
  * @old_timeout: for internal use
  * @loading_timeout: the timeout to wait for the fallback mechanism before
  * giving up, in seconds.
  */
 struct firmware_fallback_config {
unsigned int force_sysfs_fallback;
+   unsigned int ignore_sysfs_fallback;
int old_timeout;
int loading_timeout;
 };
@@ -54,6 +58,15 @@ struct ctl_table firmware_config_table[] = {
.extra1 = ,
.extra2 = ,
},
+   {
+   .procname   = "ignore_sysfs_fallback",
+   .data   = _fallback_config.ignore_sysfs_fallback,
+   .maxlen = sizeof(unsigned int),
+   .mode   = 0644,
+   .proc_handler   = proc_douintvec_minmax,
+   .extra1 = ,
+   .extra2 = ,
+   },
{ }
 };
 EXPORT_SYMBOL_GPL(firmware_config_table);
@@ -683,6 +696,11 @@ static bool fw_force_sysfs_fallback(unsigned int opt_flags)
 
 static bool fw_run_sysfs_fallback(unsigned int opt_flags)
 {
+   if (fw_fallback_config.ignore_sysfs_fallback) {
+   pr_info_once("Ignoring firmware sysfs fallback due to debugfs 
knob\n");
+   return false;
+   }
+
if ((opt_flags & FW_OPT_NOFALLBACK))
return false;
 
-- 
2.16.1