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Received: from 30.221.128.140(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0W6eXBwH_1715943155) by smtp.aliyun-inc.com; Fri, 17 May 2024 18:52:36 +0800 Message-ID: <1b906ebc-a850-4974-8ceb-e33d88768bf1@linux.alibaba.com> Date: Fri, 17 May 2024 18:52:34 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/2] ocfs2: add bounds checking to ocfs2_xattr_find_entry() To: Ferry Meng , lei lu , akpm Cc: linux-kernel@vger.kernel.org, Mark Fasheh , Joel Becker , ocfs2-devel@lists.linux.dev References: <20240517094147.87133-1-mengferry@linux.alibaba.com> <20240517094147.87133-2-mengferry@linux.alibaba.com> Content-Language: en-US From: Joseph Qi In-Reply-To: <20240517094147.87133-2-mengferry@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/17/24 5:41 PM, Ferry Meng wrote: > Add a paranoia check to make sure it doesn't stray beyond valid memory > region containing ocfs2 xattr entries when scanning for a match. > It will prevent out-of-bound access in case of crafted images. > > Signed-off-by: Ferry Meng Reported-by: lei lu Reviewed-by: Joseph Qi > --- > fs/ocfs2/xattr.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c > index 3b81213ed7b8..8aea94c90739 100644 > --- a/fs/ocfs2/xattr.c > +++ b/fs/ocfs2/xattr.c > @@ -1062,7 +1062,7 @@ ssize_t ocfs2_listxattr(struct dentry *dentry, > return i_ret + b_ret; > } > > -static int ocfs2_xattr_find_entry(int name_index, > +static int ocfs2_xattr_find_entry(struct inode *inode, int name_index, > const char *name, > struct ocfs2_xattr_search *xs) > { > @@ -1076,6 +1076,10 @@ static int ocfs2_xattr_find_entry(int name_index, > name_len = strlen(name); > entry = xs->here; > for (i = 0; i < le16_to_cpu(xs->header->xh_count); i++) { > + if ((void *)entry >= xs->end) { > + ocfs2_error(inode->i_sb, "corrupted xattr entries"); > + return -EFSCORRUPTED; > + } > cmp = name_index - ocfs2_xattr_get_type(entry); > if (!cmp) > cmp = name_len - entry->xe_name_len; > @@ -1166,7 +1170,7 @@ static int ocfs2_xattr_ibody_get(struct inode *inode, > xs->base = (void *)xs->header; > xs->here = xs->header->xh_entries; > > - ret = ocfs2_xattr_find_entry(name_index, name, xs); > + ret = ocfs2_xattr_find_entry(inode, name_index, name, xs); > if (ret) > return ret; > size = le64_to_cpu(xs->here->xe_value_size); > @@ -2698,7 +2702,7 @@ static int ocfs2_xattr_ibody_find(struct inode *inode, > > /* Find the named attribute. */ > if (oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL) { > - ret = ocfs2_xattr_find_entry(name_index, name, xs); > + ret = ocfs2_xattr_find_entry(inode, name_index, name, xs); > if (ret && ret != -ENODATA) > return ret; > xs->not_found = ret; > @@ -2833,7 +2837,7 @@ static int ocfs2_xattr_block_find(struct inode *inode, > xs->end = (void *)(blk_bh->b_data) + blk_bh->b_size; > xs->here = xs->header->xh_entries; > > - ret = ocfs2_xattr_find_entry(name_index, name, xs); > + ret = ocfs2_xattr_find_entry(inode, name_index, name, xs); > } else > ret = ocfs2_xattr_index_block_find(inode, blk_bh, > name_index,