From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6DD021D04BA; Wed, 2 Oct 2024 13:58:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727877527; cv=none; b=K0TBnknzNwVLp3BFQIWmROCYcaLzRqo2eDVrAvbOrOn/uRL3V2riGejEyZkWa0Pc6b3reFAMysYh/iuySwyEvCGg8l4l1TbaPcl6GDwtElvuq4QywSO9yWyUCfigjNPAOjk4JnhA9c8+OwQ8yNY7bP9sBTYQyienGKnul4Wv6Tw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727877527; c=relaxed/simple; bh=FelYdmcIldzmmP2w7nn9o1Z9/dtYLkxoLepGJ8ZCFQs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=tA4M0mX7b3PIoaKJtmhc4+8lpQMzKsroKGNqb5lzo3DH88/gXk8sccJMiIt5lklSQVyXACF7PBr6cf72Uwa6X293Nd11Wc7exu8dYiF3SMKetUw7/S1tvvuB2MHvds15hn386K3C05daWY7r1NWlWPYmoCX9z1smvnlqGPnHHY4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vj7u+3gO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="vj7u+3gO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 804D7C4CEC2; Wed, 2 Oct 2024 13:58:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1727877527; bh=FelYdmcIldzmmP2w7nn9o1Z9/dtYLkxoLepGJ8ZCFQs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vj7u+3gOMtE6NtuHWeZF77ez4T7IoAvvnG2V5byNLKL3E5+HFnVy/zX7iLsLhgTKj wGCffUWbMzOC8Rt/QtC4NGXD3P3v+Vo17zDmBFXWNw3yx6octYtJ0ldoW4XK/RL5ve mwbJKDD3w5OBGuaLma0hWYhaHowc7VfyN2cL6hpU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Colin Walters , Gao Xiang , Sasha Levin Subject: [PATCH 6.10 109/634] erofs: fix incorrect symlink detection in fast symlink Date: Wed, 2 Oct 2024 14:53:29 +0200 Message-ID: <20241002125815.416941859@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241002125811.070689334@linuxfoundation.org> References: <20241002125811.070689334@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gao Xiang [ Upstream commit 9ed50b8231e37b1ae863f5dec8153b98d9f389b4 ] Fast symlink can be used if the on-disk symlink data is stored in the same block as the on-disk inode, so we don’t need to trigger another I/O for symlink data. However, currently fs correction could be reported _incorrectly_ if inode xattrs are too large. In fact, these should be valid images although they cannot be handled as fast symlinks. Many thanks to Colin for reporting this! Reported-by: Colin Walters Reported-by: https://honggfuzz.dev/ Link: https://lore.kernel.org/r/bb2dd430-7de0-47da-ae5b-82ab2dd4d945@app.fastmail.com Fixes: 431339ba9042 ("staging: erofs: add inode operations") [ Note that it's a runtime misbehavior instead of a security issue. ] Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20240909031911.1174718-1-hsiangkao@linux.alibaba.com Signed-off-by: Sasha Levin --- fs/erofs/inode.c | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-) diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c index 5f6439a63af79..f2cab9e4f3bcd 100644 --- a/fs/erofs/inode.c +++ b/fs/erofs/inode.c @@ -178,12 +178,14 @@ static int erofs_fill_symlink(struct inode *inode, void *kaddr, unsigned int m_pofs) { struct erofs_inode *vi = EROFS_I(inode); - unsigned int bsz = i_blocksize(inode); + loff_t off; char *lnk; - /* if it cannot be handled with fast symlink scheme */ - if (vi->datalayout != EROFS_INODE_FLAT_INLINE || - inode->i_size >= bsz || inode->i_size < 0) { + m_pofs += vi->xattr_isize; + /* check if it cannot be handled with fast symlink scheme */ + if (vi->datalayout != EROFS_INODE_FLAT_INLINE || inode->i_size < 0 || + check_add_overflow(m_pofs, inode->i_size, &off) || + off > i_blocksize(inode)) { inode->i_op = &erofs_symlink_iops; return 0; } @@ -192,16 +194,6 @@ static int erofs_fill_symlink(struct inode *inode, void *kaddr, if (!lnk) return -ENOMEM; - m_pofs += vi->xattr_isize; - /* inline symlink data shouldn't cross block boundary */ - if (m_pofs + inode->i_size > bsz) { - kfree(lnk); - erofs_err(inode->i_sb, - "inline data cross block boundary @ nid %llu", - vi->nid); - DBG_BUGON(1); - return -EFSCORRUPTED; - } memcpy(lnk, kaddr + m_pofs, inode->i_size); lnk[inode->i_size] = '\0'; -- 2.43.0