firmware: qemu_fw_cfg: constify 'struct bin_attribute'

[PATCH] firmware: qemu_fw_cfg: constify 'struct bin_attribute'

Posted by Thomas Weißschuh 2 months, 3 weeks ago

The sysfs core now allows instances of 'struct bin_attribute' to be
moved into read-only memory. Make use of that to protect them against
accidental or malicious modifications.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 drivers/firmware/qemu_fw_cfg.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index d58da3e4500a5e230b7da9a75e4d70df7c38c542..2615fb780e3c4500db36d4746880455f05479f1f 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -460,7 +460,7 @@ static const struct kobj_type fw_cfg_sysfs_entry_ktype = {
 
 /* raw-read method and attribute */
 static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
-				     struct bin_attribute *bin_attr,
+				     const struct bin_attribute *bin_attr,
 				     char *buf, loff_t pos, size_t count)
 {
 	struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
@@ -474,9 +474,9 @@ static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
 	return fw_cfg_read_blob(entry->select, buf, pos, count);
 }
 
-static struct bin_attribute fw_cfg_sysfs_attr_raw = {
+static const struct bin_attribute fw_cfg_sysfs_attr_raw = {
 	.attr = { .name = "raw", .mode = S_IRUSR },
-	.read = fw_cfg_sysfs_read_raw,
+	.read_new = fw_cfg_sysfs_read_raw,
 };
 
 /*

---
base-commit: 7f5b6a8ec18e3add4c74682f60b90c31bdf849f2
change-id: 20250114-sysfs-const-bin_attr-qemu_fw_cfg-fa4a95934904

Best regards,
-- 
Thomas Weißschuh <linux@weissschuh.net>

Re: [PATCH] firmware: qemu_fw_cfg: constify 'struct bin_attribute'

Posted by Michael S. Tsirkin 2 months, 3 weeks ago

On Tue, Jan 14, 2025 at 10:50:20PM +0100, Thomas Weißschuh wrote:
> The sysfs core now allows instances of 'struct bin_attribute' to be
> moved into read-only memory. Make use of that to protect them against
> accidental or malicious modifications.
> 
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

why not

Acked-by: Michael S. Tsirkin <mst@redhat.com>

> ---
>  drivers/firmware/qemu_fw_cfg.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index d58da3e4500a5e230b7da9a75e4d70df7c38c542..2615fb780e3c4500db36d4746880455f05479f1f 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -460,7 +460,7 @@ static const struct kobj_type fw_cfg_sysfs_entry_ktype = {
>  
>  /* raw-read method and attribute */
>  static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
> -				     struct bin_attribute *bin_attr,
> +				     const struct bin_attribute *bin_attr,
>  				     char *buf, loff_t pos, size_t count)
>  {
>  	struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
> @@ -474,9 +474,9 @@ static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
>  	return fw_cfg_read_blob(entry->select, buf, pos, count);
>  }
>  
> -static struct bin_attribute fw_cfg_sysfs_attr_raw = {
> +static const struct bin_attribute fw_cfg_sysfs_attr_raw = {
>  	.attr = { .name = "raw", .mode = S_IRUSR },
> -	.read = fw_cfg_sysfs_read_raw,
> +	.read_new = fw_cfg_sysfs_read_raw,
>  };
>  
>  /*
> 
> ---
> base-commit: 7f5b6a8ec18e3add4c74682f60b90c31bdf849f2
> change-id: 20250114-sysfs-const-bin_attr-qemu_fw_cfg-fa4a95934904
> 
> Best regards,
> -- 
> Thomas Weißschuh <linux@weissschuh.net>
>

Re: [PATCH] firmware: qemu_fw_cfg: constify 'struct bin_attribute'

Posted by Gabriel L. Somlo 2 months, 3 weeks ago

On Tue, Jan 14, 2025 at 10:50:20PM +0100, Thomas Weißschuh wrote:
> The sysfs core now allows instances of 'struct bin_attribute' to be
> moved into read-only memory. Make use of that to protect them against
> accidental or malicious modifications.
> 
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

Acked-by: Gabriel Somlo <somlo@cmu.edu>

Thanks,
--Gabriel

> ---
>  drivers/firmware/qemu_fw_cfg.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index d58da3e4500a5e230b7da9a75e4d70df7c38c542..2615fb780e3c4500db36d4746880455f05479f1f 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -460,7 +460,7 @@ static const struct kobj_type fw_cfg_sysfs_entry_ktype = {
>  
>  /* raw-read method and attribute */
>  static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
> -				     struct bin_attribute *bin_attr,
> +				     const struct bin_attribute *bin_attr,
>  				     char *buf, loff_t pos, size_t count)
>  {
>  	struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
> @@ -474,9 +474,9 @@ static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
>  	return fw_cfg_read_blob(entry->select, buf, pos, count);
>  }
>  
> -static struct bin_attribute fw_cfg_sysfs_attr_raw = {
> +static const struct bin_attribute fw_cfg_sysfs_attr_raw = {
>  	.attr = { .name = "raw", .mode = S_IRUSR },
> -	.read = fw_cfg_sysfs_read_raw,
> +	.read_new = fw_cfg_sysfs_read_raw,
>  };
>  
>  /*
> 
> ---
> base-commit: 7f5b6a8ec18e3add4c74682f60b90c31bdf849f2
> change-id: 20250114-sysfs-const-bin_attr-qemu_fw_cfg-fa4a95934904
> 
> Best regards,
> -- 
> Thomas Weißschuh <linux@weissschuh.net>
>