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 17C9632470F for ; Fri, 1 May 2026 19:11:53 +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=1777662714; cv=none; b=ksPdSK1V3oQEn8EtTGjLlLpb+hAAZyQVPVN2veIwEIcKwAMbACC64xvxfVVSq2rZCXiaq9ODwAE07EWVugFORPHpu9MQKP8V0hWZtdOKe7MS28I3X45r+Li8VFcc3KQHUGbdUQkpeGOIZUkgYRqmYh4w6FcCxFL+1XsEMIgIfew= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777662714; c=relaxed/simple; bh=usE6/vowvYfOtzxm284H+XthxgQheG4tQyFKhthO6S4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DbVA2vO0mbKQKi5Y7CEabpOAYqZtXNqH7gg33gMzzibEdCYYyfu9WNx9cSHV5ohtVWJfIJrj+rOAhKSGNl0GwMyArlScPsdmoSZi7WP2+qVenaG2n6dF1gEZ3GRc9lB/bgvpkmSgLfL1OTQ27dvcfRFjQTpwMfX3wWy3X4zuCBc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QGk7XmE/; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QGk7XmE/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 03ED1C2BCB4; Fri, 1 May 2026 19:11:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777662713; bh=usE6/vowvYfOtzxm284H+XthxgQheG4tQyFKhthO6S4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QGk7XmE/XeJEm0m9aZfVaAR5JI2cPMvlCrkPQEREFa0XfmMKvylDYCWmFU80nSbNd S0RFgwQxAN5EUsIMr3akPDb6eVfd6S91mQ/+YA67+aGmPH6uW/KtKoxLTqmlw1p1rO c6vV71EPa92NZ4laU+jkBoU+ahB4aEuQ8Torm8fbaAIaTfUHdti5PTRazJt1EoGig5 Cdv06t/6ovEzWem6AEOvZpptNNQKSbVyUbrAg3IGjF1kIXDWyMPA1u4uUoSKkxBAf+ HYZCDdgDES9rXxNdwmQUmFftjPjou3+Wd+UIrRrp7n/mKKXIu0gRQxVmH5V6FfTpWt ios6jQVyKctMg== From: Sasha Levin To: stable@vger.kernel.org Cc: Gao Xiang , Yuhao Jiang , Junrui Luo , Chao Yu , Sasha Levin Subject: [PATCH 5.10.y] erofs: fix the out-of-bounds nameoff handling for trailing dirents Date: Fri, 1 May 2026 15:11:50 -0400 Message-ID: <20260501191150.3973995-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026050132-spender-underfoot-6d7b@gregkh> References: <2026050132-spender-underfoot-6d7b@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Gao Xiang [ Upstream commit d18a3b5d337fa412a38e776e6b4b857a58836575 ] Currently we already have boundary-checks for nameoffs, but the trailing dirents are special since the namelens are calculated with strnlen() with unchecked nameoffs. If a crafted EROFS has a trailing dirent with nameoff >= maxsize, maxsize - nameoff can underflow, causing strnlen() to read past the directory block. nameoff0 should also be verified to be a multiple of `sizeof(struct erofs_dirent)` as well [1]. [1] https://sashiko.dev/#/patchset/20260416063511.3173774-1-hsiangkao%40linux.alibaba.com Fixes: 3aa8ec716e52 ("staging: erofs: add directory operations") Fixes: 33bac912840f ("staging: erofs: keep corrupted fs from crashing kernel in erofs_readdir()") Reported-by: Yuhao Jiang Reported-by: Junrui Luo Closes: https://lore.kernel.org/r/A0FD7E0F-7558-49B0-8BC8-EB1ECDB2479A@outlook.com Cc: stable@vger.kernel.org Signed-off-by: Gao Xiang Reviewed-by: Chao Yu [ replaced upstream `bsz` with `PAGE_SIZE` and `sizeof(*de)` with `sizeof(struct erofs_dirent)` ] Signed-off-by: Sasha Levin --- fs/erofs/dir.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/fs/erofs/dir.c b/fs/erofs/dir.c index 2776bb832127d..79c83218e9560 100644 --- a/fs/erofs/dir.c +++ b/fs/erofs/dir.c @@ -38,20 +38,18 @@ static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx, nameoff = le16_to_cpu(de->nameoff); de_name = (char *)dentry_blk + nameoff; - /* the last dirent in the block? */ - if (de + 1 >= end) - de_namelen = strnlen(de_name, maxsize - nameoff); - else + /* non-trailing dirent in the directory block? */ + if (de + 1 < end) de_namelen = le16_to_cpu(de[1].nameoff) - nameoff; + else if (maxsize <= nameoff) + goto err_bogus; + else + de_namelen = strnlen(de_name, maxsize - nameoff); - /* a corrupted entry is found */ - if (nameoff + de_namelen > maxsize || - de_namelen > EROFS_NAME_LEN) { - erofs_err(dir->i_sb, "bogus dirent @ nid %llu", - EROFS_I(dir)->nid); - DBG_BUGON(1); - return -EFSCORRUPTED; - } + /* a corrupted entry is found (including negative namelen) */ + if (!in_range32(de_namelen, 1, EROFS_NAME_LEN) || + nameoff + de_namelen > maxsize) + goto err_bogus; debug_one_dentry(d_type, de_name, de_namelen); if (!dir_emit(ctx, de_name, de_namelen, @@ -63,6 +61,10 @@ static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx, } *ofs = maxsize; return 0; +err_bogus: + erofs_err(dir->i_sb, "bogus dirent @ nid %llu", EROFS_I(dir)->nid); + DBG_BUGON(1); + return -EFSCORRUPTED; } static int erofs_readdir(struct file *f, struct dir_context *ctx) @@ -96,8 +98,8 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx) nameoff = le16_to_cpu(de->nameoff); - if (nameoff < sizeof(struct erofs_dirent) || - nameoff >= PAGE_SIZE) { + if (!nameoff || nameoff >= PAGE_SIZE || + (nameoff % sizeof(struct erofs_dirent))) { erofs_err(dir->i_sb, "invalid de[0].nameoff %u @ nid %llu", nameoff, EROFS_I(dir)->nid); -- 2.53.0