[PATCH AUTOSEL 4.9 02/11] nfs: Fix potential posix_acl refcnt leak in nfs3_set_acl

Sasha Levin
2020-05-07T14:30:31Z

From: Andreas Gruenbacher <agruenba@redhat.com>

[ Upstream commit 7648f939cb919b9d15c21fff8cd9eba908d595dc ]

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>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 720d92f5abfb8..6c378435fa291 100644
--- a/fs/nfs/nfs3acl.c
+++ b/fs/nfs/nfs3acl.c
@@ -252,37 +252,45 @@ 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[] = {
--
2.20.1