[PATCH] cifs: fix potential double free during failed mount

[PATCH] cifs: fix potential double free during failed mount

[Ronnie Sahlberg]

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2088799

Signed-off-by: Roberto Bergantinos <rbergant@redhat.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
 fs/cifs/cifsfs.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index f539a39d47f5..12c872800326 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -838,7 +838,7 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
 	      int flags, struct smb3_fs_context *old_ctx)
 {
 	int rc;
-	struct super_block *sb;
+	struct super_block *sb = NULL;
 	struct cifs_sb_info *cifs_sb = NULL;
 	struct cifs_mnt_data mnt_data;
 	struct dentry *root;
@@ -934,9 +934,11 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
 	return root;
 out:
 	if (cifs_sb) {
-		kfree(cifs_sb->prepath);
-		smb3_cleanup_fs_context(cifs_sb->ctx);
-		kfree(cifs_sb);
+		if (!sb || IS_ERR(sb)) {  /* otherwise kill_sb will handle */
+			kfree(cifs_sb->prepath);
+			smb3_cleanup_fs_context(cifs_sb->ctx);
+			kfree(cifs_sb);
+		}
 	}
 	return root;
 }
-- 
2.35.3

Re: [PATCH] cifs: fix potential double free during failed mount

[Steve French]

added cc:stable and merged into cifs-2.6.git for-next

On Mon, May 30, 2022 at 10:01 PM Ronnie Sahlberg <lsahlber@redhat.com> wrote:
>
> RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2088799
>
> Signed-off-by: Roberto Bergantinos <rbergant@redhat.com>
> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
> ---
>  fs/cifs/cifsfs.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index f539a39d47f5..12c872800326 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -838,7 +838,7 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
>               int flags, struct smb3_fs_context *old_ctx)
>  {
>         int rc;
> -       struct super_block *sb;
> +       struct super_block *sb = NULL;
>         struct cifs_sb_info *cifs_sb = NULL;
>         struct cifs_mnt_data mnt_data;
>         struct dentry *root;
> @@ -934,9 +934,11 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
>         return root;
>  out:
>         if (cifs_sb) {
> -               kfree(cifs_sb->prepath);
> -               smb3_cleanup_fs_context(cifs_sb->ctx);
> -               kfree(cifs_sb);
> +               if (!sb || IS_ERR(sb)) {  /* otherwise kill_sb will handle */
> +                       kfree(cifs_sb->prepath);
> +                       smb3_cleanup_fs_context(cifs_sb->ctx);
> +                       kfree(cifs_sb);
> +               }
>         }
>         return root;
>  }
> --
> 2.35.3
>


-- 
Thanks,

Steve