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 5AE73BA34; Mon, 6 Jan 2025 15:57:58 +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=1736179078; cv=none; b=McPSXZElkwqMpnPjgnrJD5cso3ahUPfdIh3T4knvGz5torZqB0UjmAJnHC9GxrUl5yFVo85UN/HJH8OBsUfpuxyCnYmxQQRN/6YnIVZMcQVyeyNh/FfxVlJ+QvIGYZd7HLtnAbLk9nP/NPD5vSv3MNyreqHtosdQ1Spm758T0NU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736179078; c=relaxed/simple; bh=n8a4P3paj2GOuUILt3TeU7iZyufBVUDAL+O6r6x0IhU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=f6SDoSHJvCMMV0BIcTUc7Bfj1Aer78rHtAMeazxLrl0p4TImNE6tDZukd8Twl9AQpz7UC1XUhS3e1zrImeVZNksMjQCCr0AO3JLG4i4bcf5vcO0gmqE7bntfBLIZzOf3WvzHE2Co/kdcZ0wFO8JWTuv6WqpvXpF+WMij0EtSSG4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=X2L08WnA; 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="X2L08WnA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D59B9C4CED2; Mon, 6 Jan 2025 15:57:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1736179078; bh=n8a4P3paj2GOuUILt3TeU7iZyufBVUDAL+O6r6x0IhU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X2L08WnAMUVevLCZLHrp9Dm8215oRNUgZW8BXhLfsuiUbsflWmRAp1A0Y+Gca52jS Bz1GwAHDoXpNnlpLIbMSaqAzx+f8F/SaLIixSy+MdkLH8jURiiLN2CI1xr0aqxu3vK PEi2p3dcimFl3nlxGchkMwr+BibcICohdCGr8qiw= 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 5.4 09/93] erofs: fix incorrect symlink detection in fast symlink Date: Mon, 6 Jan 2025 16:16:45 +0100 Message-ID: <20250106151129.050066936@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250106151128.686130933@linuxfoundation.org> References: <20250106151128.686130933@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gao Xiang commit 9ed50b8231e37b1ae863f5dec8153b98d9f389b4 upstream. 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. ] Link: https://lore.kernel.org/r/20240909031911.1174718-1-hsiangkao@linux.alibaba.com [ Gao Xiang: fix 5.4.y build warning due to `check_add_overflow`. ] Signed-off-by: Gao Xiang 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 ba981076d6f2..af90d3d70a08 100644 --- a/fs/erofs/inode.c +++ b/fs/erofs/inode.c @@ -198,11 +198,14 @@ static int erofs_fill_symlink(struct inode *inode, void *data, unsigned int m_pofs) { struct erofs_inode *vi = EROFS_I(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 >= PAGE_SIZE || 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((loff_t)m_pofs, inode->i_size, &off) || + off > i_blocksize(inode)) { inode->i_op = &erofs_symlink_iops; return 0; } @@ -211,17 +214,6 @@ static int erofs_fill_symlink(struct inode *inode, void *data, if (!lnk) return -ENOMEM; - m_pofs += vi->xattr_isize; - /* inline symlink data shouldn't cross page boundary as well */ - if (m_pofs + inode->i_size > PAGE_SIZE) { - kfree(lnk); - erofs_err(inode->i_sb, - "inline data cross block boundary @ nid %llu", - vi->nid); - DBG_BUGON(1); - return -EFSCORRUPTED; - } - memcpy(lnk, data + m_pofs, inode->i_size); lnk[inode->i_size] = '\0'; -- 2.39.5