When jffs2 has to retry reading xattrs we need to reset
the buffer pointer. Otherwise we return old xattrs from the
previous iteration which leads to a inconsistency between
the number of bytes we return and the real list size.

Cc: <sta...@vger.kernel.org>
Cc: Andreas Gruenbacher <agrue...@redhat.com>
Fixes: 764a5c6b1fa4 ("xattr handlers: Simplify list operation")
Signed-off-by: Richard Weinberger <rich...@nod.at>
---
Andreas,

since you maintain the attr package too, I report it right here. :-)
This jffs2 bug lead to a crash in attr_list().

for() will loop to crash when there is no trailing \0 in the
list of xattrs.

for (l = lbuf; l != lbuf + length; l = strchr(l, '\0') + 1) {
        if (api_unconvert(name, l, flags))
                continue;

...
}

I suggest changing the loop condition to something like l < lbuf + length.

Thanks,
//richard
---
 fs/jffs2/xattr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/jffs2/xattr.c b/fs/jffs2/xattr.c
index da3e18503c65..0cb322eb9516 100644
--- a/fs/jffs2/xattr.c
+++ b/fs/jffs2/xattr.c
@@ -967,6 +967,7 @@ ssize_t jffs2_listxattr(struct dentry *dentry, char 
*buffer, size_t size)
        struct jffs2_xattr_ref *ref, **pref;
        struct jffs2_xattr_datum *xd;
        const struct xattr_handler *xhandle;
+       char *orig_buffer = buffer;
        const char *prefix;
        ssize_t prefix_len, len, rc;
        int retry = 0;
@@ -977,6 +978,7 @@ ssize_t jffs2_listxattr(struct dentry *dentry, char 
*buffer, size_t size)
 
        down_read(&c->xattr_sem);
  retry:
+       buffer = orig_buffer;
        len = 0;
        for (ref=ic->xref, pref=&ic->xref; ref; pref=&ref->next, ref=ref->next) 
{
                BUG_ON(ref->ic != ic);
-- 
2.20.0

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