From: Jia-Ju Bai baijiaju1990@gmail.com
[ Upstream commit 56e94ea132bb5c2c1d0b60a6aeb34dcb7d71a53d ]
In ocfs2_xa_prepare_entry(), there is an if statement on line 2136 to check whether loc->xl_entry is NULL:
if (loc->xl_entry)
When loc->xl_entry is NULL, it is used on line 2158:
ocfs2_xa_add_entry(loc, name_hash); loc->xl_entry->xe_name_hash = cpu_to_le32(name_hash); loc->xl_entry->xe_name_offset = cpu_to_le16(loc->xl_size);
and line 2164:
ocfs2_xa_add_namevalue(loc, xi); loc->xl_entry->xe_value_size = cpu_to_le64(xi->xi_value_len); loc->xl_entry->xe_name_len = xi->xi_name_len;
Thus, possible null-pointer dereferences may occur.
To fix these bugs, if loc-xl_entry is NULL, ocfs2_xa_prepare_entry() abnormally returns with -EINVAL.
These bugs are found by a static analysis tool STCheck written by us.
[akpm@linux-foundation.org: remove now-unused ocfs2_xa_add_entry()] Link: http://lkml.kernel.org/r/20190726101447.9153-1-baijiaju1990@gmail.com Signed-off-by: Jia-Ju Bai baijiaju1990@gmail.com Reviewed-by: Joseph Qi joseph.qi@linux.alibaba.com Cc: Mark Fasheh mark@fasheh.com Cc: Joel Becker jlbec@evilplan.org Cc: Junxiao Bi junxiao.bi@oracle.com Cc: Changwei Ge gechangwei@live.cn Cc: Gang He ghe@suse.com Cc: Jun Piao piaojun@huawei.com Cc: Stephen Rothwell sfr@canb.auug.org.au Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ocfs2/xattr.c | 56 ++++++++++++++++++++---------------------------- 1 file changed, 23 insertions(+), 33 deletions(-)
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index 06faa608e5622..dfa6d45dc4dc4 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -1475,18 +1475,6 @@ static int ocfs2_xa_check_space(struct ocfs2_xa_loc *loc, return loc->xl_ops->xlo_check_space(loc, xi); }
-static void ocfs2_xa_add_entry(struct ocfs2_xa_loc *loc, u32 name_hash) -{ - loc->xl_ops->xlo_add_entry(loc, name_hash); - loc->xl_entry->xe_name_hash = cpu_to_le32(name_hash); - /* - * We can't leave the new entry's xe_name_offset at zero or - * add_namevalue() will go nuts. We set it to the size of our - * storage so that it can never be less than any other entry. - */ - loc->xl_entry->xe_name_offset = cpu_to_le16(loc->xl_size); -} - static void ocfs2_xa_add_namevalue(struct ocfs2_xa_loc *loc, struct ocfs2_xattr_info *xi) { @@ -2118,29 +2106,31 @@ static int ocfs2_xa_prepare_entry(struct ocfs2_xa_loc *loc, if (rc) goto out;
- if (loc->xl_entry) { - if (ocfs2_xa_can_reuse_entry(loc, xi)) { - orig_value_size = loc->xl_entry->xe_value_size; - rc = ocfs2_xa_reuse_entry(loc, xi, ctxt); - if (rc) - goto out; - goto alloc_value; - } + if (!loc->xl_entry) { + rc = -EINVAL; + goto out; + }
- if (!ocfs2_xattr_is_local(loc->xl_entry)) { - orig_clusters = ocfs2_xa_value_clusters(loc); - rc = ocfs2_xa_value_truncate(loc, 0, ctxt); - if (rc) { - mlog_errno(rc); - ocfs2_xa_cleanup_value_truncate(loc, - "overwriting", - orig_clusters); - goto out; - } + if (ocfs2_xa_can_reuse_entry(loc, xi)) { + orig_value_size = loc->xl_entry->xe_value_size; + rc = ocfs2_xa_reuse_entry(loc, xi, ctxt); + if (rc) + goto out; + goto alloc_value; + } + + if (!ocfs2_xattr_is_local(loc->xl_entry)) { + orig_clusters = ocfs2_xa_value_clusters(loc); + rc = ocfs2_xa_value_truncate(loc, 0, ctxt); + if (rc) { + mlog_errno(rc); + ocfs2_xa_cleanup_value_truncate(loc, + "overwriting", + orig_clusters); + goto out; } - ocfs2_xa_wipe_namevalue(loc); - } else - ocfs2_xa_add_entry(loc, name_hash); + } + ocfs2_xa_wipe_namevalue(loc);
/* * If we get here, we have a blank entry. Fill it. We grow our