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SubjectRe: [PATCH] nfs: Fix potential posix_acl refcnt leak in nfs3_set_acl
Date
On Mon, 2020-04-20 at 15:51 +0200, Andreas Gruenbacher wrote:
> nfs3_set_acl keeps track of the acl it allocated locally to determine
> if an acl
> needs to be released at the end. This results in a memory leak when
> the
> function allocates an acl as well as a default acl. Fix by releasing
> acls
> that differ from the acl originally passed into nfs3_set_acl.
>
> Fixes: b7fa0554cf1b ("[PATCH] NFS: Add support for NFSv3 ACLs")
> Reported-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> ---
> fs/nfs/nfs3acl.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/fs/nfs/nfs3acl.c b/fs/nfs/nfs3acl.c
> index c5c3fc6e6c60..26c94b32d6f4 100644
> --- a/fs/nfs/nfs3acl.c
> +++ b/fs/nfs/nfs3acl.c
> @@ -253,37 +253,45 @@ int nfs3_proc_setacls(struct inode *inode,
> struct posix_acl *acl,
>
> int nfs3_set_acl(struct inode *inode, struct posix_acl *acl, int
> type)
> {
> - struct posix_acl *alloc = NULL, *dfacl = NULL;
> + struct posix_acl *orig = acl, *dfacl = NULL, *alloc;
> int status;
>
> if (S_ISDIR(inode->i_mode)) {
> switch(type) {
> case ACL_TYPE_ACCESS:
> - alloc = dfacl = get_acl(inode,
> ACL_TYPE_DEFAULT);
> + alloc = get_acl(inode, ACL_TYPE_DEFAULT);
> if (IS_ERR(alloc))
> goto fail;
> + dfacl = alloc;
> break;
>
> case ACL_TYPE_DEFAULT:
> - dfacl = acl;
> - alloc = acl = get_acl(inode, ACL_TYPE_ACCESS);
> + alloc = get_acl(inode, ACL_TYPE_ACCESS);
> if (IS_ERR(alloc))
> goto fail;
> + dfacl = acl;
> + acl = alloc;
> break;
> }
> }
>
> if (acl == NULL) {
> - alloc = acl = posix_acl_from_mode(inode->i_mode,
> GFP_KERNEL);
> + alloc = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
> if (IS_ERR(alloc))
> goto fail;
> + acl = alloc;
> }
> status = __nfs3_proc_setacls(inode, acl, dfacl);
> - posix_acl_release(alloc);
> +out:
> + if (acl != orig)
> + posix_acl_release(acl);
> + if (dfacl != orig)
> + posix_acl_release(dfacl);
> return status;
>
> fail:
> - return PTR_ERR(alloc);
> + status = PTR_ERR(alloc);
> + goto out;
> }
>
> const struct xattr_handler *nfs3_xattr_handlers[] = {
>
> base-commit: ae83d0b416db002fe95601e7f97f64b59514d936

Thanks Andreas! This one looks good.

--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com


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