ovl: copy_up_xattr(): use strnlen (8b326c61) · Commits · 戴 / test

Be defensive about what underlying fs provides us in the returned xattr list buffer. strlen() may overrun the buffer, so use strnlen() and WARN if the contents are not properly null terminated. Signed-off-by:

Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org>

fs/overlayfs/copy_up.c

+11 −1

Original line number	Diff line number	Diff line
		@@ -57,6 +57,7 @@ int ovl_copy_xattr(struct dentry old, struct dentry new)
		ssize_t list_size, size, value_size = 0;
		char buf, name, *value = NULL;
		int uninitialized_var(error);
		size_t slen;

		if (!old->d_inode->i_op->getxattr \|\|
		!new->d_inode->i_op->getxattr)
		@@ -79,7 +80,16 @@ int ovl_copy_xattr(struct dentry old, struct dentry new)
		goto out;
		}

		for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {
		for (name = buf; list_size; name += slen) {
		slen = strnlen(name, list_size) + 1;

		/* underlying fs providing us with an broken xattr list? */
		if (WARN_ON(slen > list_size)) {
		error = -EIO;
		break;
		}
		list_size -= slen;

		if (ovl_is_private_xattr(name))
		continue;
		retry:

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