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fs: ocfs2: fix possible null-pointer dereferences in ocfs2_xa_prepare_entry()

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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>
This commit is contained in:
Jia-Ju Bai 2019-10-06 17:57:50 -07:00 committed by Linus Torvalds
parent 7a243c82ea
commit 56e94ea132
1 changed files with 23 additions and 33 deletions
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56
fs/ocfs2/xattr.c
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@ -1490,18 +1490,6 @@ 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)
{
@ -2133,29 +2121,31 @@ 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