diff mbox series

[net,v3,2/2] ax25: Change kfree() in ax25_dev_free() to ax25_dev_put()

Message ID 53925353450dea9a705d67ad225b589e8508042c.1715002910.git.duoming@zju.edu.cn (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series ax25: Fix issues of ax25_dev and net_device | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net, async
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 17 this patch: 928
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang fail Errors and warnings before: 18 this patch: 938
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn fail Errors and warnings before: 17 this patch: 939
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 21 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Duoming Zhou May 6, 2024, 2:08 p.m. UTC
The object "ax25_dev" is managed by reference counting. Thus it should
not be directly released by a kfree() call in ax25_dev_free(). Replace
it with a ax25_dev_put() call instead.

Fixes: d01ffb9eee4a ("ax25: add refcount in ax25_dev to avoid UAF bugs")
Suggested-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
---
Changes in v3:
  - Make commit messages more clearer.

 net/ax25/ax25_dev.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

Comments

Markus Elfring May 6, 2024, 3:50 p.m. UTC | #1
> Replace it with a ax25_dev_put() call instead.> ---
> Changes in v3:
>   - Make commit messages more clearer.> +++ b/net/ax25/ax25_dev.c
> @@ -188,16 +188,13 @@ struct net_device *ax25_fwd_dev(struct net_device *dev)
>   */
>  void __exit ax25_dev_free(void)
>  {> -	ax25_dev = ax25_dev_list;
> -	while (ax25_dev != NULL) {
> -		s        = ax25_dev;
> -		netdev_put(ax25_dev->dev, &ax25_dev->dev_tracker);
> -		ax25_dev = ax25_dev->next;
> -		kfree(s);
> +	list_for_each_entry_safe(s, n, &ax25_dev_list, list) {
> +		netdev_put(s->dev, &s->dev_tracker);
> +		list_del(&s->list);
> +		ax25_dev_put(s);
>  	}
> -	ax25_dev_list = NULL;
…

Can the increased application of the Linux list API be offered as
a separate update step?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.9-rc7#n81

Regards,
Markus
diff mbox series

Patch

diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index fbaaba0351e..8ee028e752f 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -188,16 +188,13 @@  struct net_device *ax25_fwd_dev(struct net_device *dev)
  */
 void __exit ax25_dev_free(void)
 {
-	ax25_dev *s, *ax25_dev;
+	ax25_dev *s, *n;
 
 	spin_lock_bh(&ax25_dev_lock);
-	ax25_dev = ax25_dev_list;
-	while (ax25_dev != NULL) {
-		s        = ax25_dev;
-		netdev_put(ax25_dev->dev, &ax25_dev->dev_tracker);
-		ax25_dev = ax25_dev->next;
-		kfree(s);
+	list_for_each_entry_safe(s, n, &ax25_dev_list, list) {
+		netdev_put(s->dev, &s->dev_tracker);
+		list_del(&s->list);
+		ax25_dev_put(s);
 	}
-	ax25_dev_list = NULL;
 	spin_unlock_bh(&ax25_dev_lock);
 }