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authorDan Carpenter <dan.carpenter@oracle.com>2015-06-19 02:00:55 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2015-06-24 01:01:07 +0300
commitc0c3a718e3ab2430a52a60d614b109e5e48e83e2 (patch)
treed4341a60d055e21310a16bcef68f4c8319f224c7 /fs/posix_acl.c
parent6b6dabc8dcefaf9997ce037c70b32d570ced9d3e (diff)
downloadlinux-c0c3a718e3ab2430a52a60d614b109e5e48e83e2.tar.xz
fs/posix_acl.c: make posix_acl_create() safer and cleaner
If posix_acl_create() returns an error code then "*acl" and "*default_acl" can be uninitialized or point to freed memory. This is a dangerous thing to do. For example, it causes a problem in ocfs2_reflink(): fs/ocfs2/refcounttree.c:4327 ocfs2_reflink() error: potentially using uninitialized 'default_acl'. I've re-written this so we set the pointers to NULL at the start. I've added a temporary "clone" variable to hold the value of "*acl" until end. Setting them to NULL means means we don't need the "no_acl" label. We may as well remove the "apply_umask" stuff forward and remove that label as well. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Joel Becker <jlbec@evilplan.org> Cc: Mark Fasheh <mfasheh@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/posix_acl.c')
-rw-r--r--fs/posix_acl.c46
1 files changed, 20 insertions, 26 deletions
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 84bb65b83570..4fb17ded7d47 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -547,51 +547,45 @@ posix_acl_create(struct inode *dir, umode_t *mode,
struct posix_acl **default_acl, struct posix_acl **acl)
{
struct posix_acl *p;
+ struct posix_acl *clone;
int ret;
+ *acl = NULL;
+ *default_acl = NULL;
+
if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
- goto no_acl;
+ return 0;
p = get_acl(dir, ACL_TYPE_DEFAULT);
- if (IS_ERR(p)) {
- if (p == ERR_PTR(-EOPNOTSUPP))
- goto apply_umask;
- return PTR_ERR(p);
+ if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
+ *mode &= ~current_umask();
+ return 0;
}
+ if (IS_ERR(p))
+ return PTR_ERR(p);
- if (!p)
- goto apply_umask;
-
- *acl = posix_acl_clone(p, GFP_NOFS);
- if (!*acl)
+ clone = posix_acl_clone(p, GFP_NOFS);
+ if (!clone)
goto no_mem;
- ret = posix_acl_create_masq(*acl, mode);
+ ret = posix_acl_create_masq(clone, mode);
if (ret < 0)
goto no_mem_clone;
- if (ret == 0) {
- posix_acl_release(*acl);
- *acl = NULL;
- }
+ if (ret == 0)
+ posix_acl_release(clone);
+ else
+ *acl = clone;
- if (!S_ISDIR(*mode)) {
+ if (!S_ISDIR(*mode))
posix_acl_release(p);
- *default_acl = NULL;
- } else {
+ else
*default_acl = p;
- }
- return 0;
-apply_umask:
- *mode &= ~current_umask();
-no_acl:
- *default_acl = NULL;
- *acl = NULL;
return 0;
no_mem_clone:
- posix_acl_release(*acl);
+ posix_acl_release(clone);
no_mem:
posix_acl_release(p);
return -ENOMEM;