Currently one requires to test four kernel configurations to test the
firmware API completely:
0)
CONFIG_FW_LOADER=y
1)
o CONFIG_FW_LOADER=y
o CONFIG_FW_LOADER_USER_HELPER=y
2)
o CONFIG_FW_LOADER=y
o CONFIG_FW_LOADER_USER_HELPER=y
o CONFIG_FW_LOADER_USER_HELPER_FALLBACK=y
3) When CONFIG_FW_LOADER=m the built-in stuff is disabled, we have
no current tests for this.
We can reduce the requirements to three kernel configurations by making
fw_config.force_sysfs_fallback a proc knob we flip on off. For kernels that
disable CONFIG_IKCONFIG_PROC this can also enable one to inspect if
CONFIG_FW_LOADER_USER_HELPER_FALLBACK was enabled at build time by checking
the proc value at boot time.
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxx>
---
drivers/base/firmware_loader/fallback.c | 1 +
drivers/base/firmware_loader/fallback.h | 4 +++-
drivers/base/firmware_loader/fallback_table.c | 17 +++++++++++++++++
kernel/sysctl.c | 11 +++++++++++
4 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c
index 9b65837256d6..45cc40933a47 100644
--- a/drivers/base/firmware_loader/fallback.c
+++ b/drivers/base/firmware_loader/fallback.c
@@ -7,6 +7,7 @@
#include <linux/security.h>
#include <linux/highmem.h>
#include <linux/umh.h>
+#include <linux/sysctl.h>
#include "fallback.h"
#include "firmware.h"
diff --git a/drivers/base/firmware_loader/fallback.h b/drivers/base/firmware_loader/fallback.h
index 550498c7fa4c..ca7e69a8417b 100644
--- a/drivers/base/firmware_loader/fallback.h
+++ b/drivers/base/firmware_loader/fallback.h
@@ -12,12 +12,14 @@
*
* @force_sysfs_fallback: force the sysfs fallback mechanism to be used
* 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.
* @old_timeout: for internal use
* @loading_timeout: the timeout to wait for the fallback mechanism before
* giving up, in seconds.
*/
struct firmware_fallback_config {
- const bool force_sysfs_fallback;
+ unsigned int force_sysfs_fallback;
int old_timeout;
int loading_timeout;
};
diff --git a/drivers/base/firmware_loader/fallback_table.c b/drivers/base/firmware_loader/fallback_table.c
index 981419044c7e..92365e053e30 100644
--- a/drivers/base/firmware_loader/fallback_table.c
+++ b/drivers/base/firmware_loader/fallback_table.c
@@ -19,6 +19,9 @@
/* Module or buit-in */
#ifdef CONFIG_FW_LOADER_USER_HELPER
+static unsigned int zero;
+static unsigned int one = 1;
+
struct firmware_fallback_config fw_fallback_config = {
.force_sysfs_fallback = IS_ENABLED(CONFIG_FW_LOADER_USER_HELPER_FALLBACK),
.loading_timeout = 60,
@@ -26,4 +29,18 @@ struct firmware_fallback_config fw_fallback_config = {
};
EXPORT_SYMBOL_GPL(fw_fallback_config);
+struct ctl_table firmware_config_table[] = {
+ {
+ .procname = "force_sysfs_fallback",
+ .data = &fw_fallback_config.force_sysfs_fallback,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = proc_douintvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+ { }
+};
+EXPORT_SYMBOL_GPL(firmware_config_table);
+
#endif
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 6c68e771e11d..7a8aa6866764 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -253,6 +253,10 @@ extern struct ctl_table random_table[];
extern struct ctl_table epoll_table[];
#endif
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+extern struct ctl_table firmware_config_table[];
+#endif
+
#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
int sysctl_legacy_va_layout;
#endif
@@ -748,6 +752,13 @@ static struct ctl_table kern_table[] = {
.mode = 0555,
.child = usermodehelper_table,
},
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+ {
+ .procname = "firmware_config",
+ .mode = 0555,
+ .child = firmware_config_table,
+ },
+#endif
{
.procname = "overflowuid",
.data = &overflowuid,
--
2.16.2
