lkml.org 
[lkml]   [2024]   [May]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v2 2/2] ocfs2: strict bound check before memcmp in ocfs2_xattr_find_entry()
From


On 5/17/24 5:41 PM, Ferry Meng wrote:
> xattr in ocfs2 maybe 'non-indexed', which saved with additional space
> requested. It's better to check if the memory is out of bound before
> memcmp, although this possibility mainly comes from crafted poisonous
> images.
>
> Signed-off-by: Ferry Meng <mengferry@linux.alibaba.com>

Reported-by: lei lu <llfamsec@gmail.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>

> ---
> fs/ocfs2/xattr.c | 15 ++++++++++-----
> 1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
> index 8aea94c90739..35c0cc2a51af 100644
> --- a/fs/ocfs2/xattr.c
> +++ b/fs/ocfs2/xattr.c
> @@ -1068,7 +1068,7 @@ static int ocfs2_xattr_find_entry(struct inode *inode, int name_index,
> {
> struct ocfs2_xattr_entry *entry;
> size_t name_len;
> - int i, cmp = 1;
> + int i, name_offset, cmp = 1;
>
> if (name == NULL)
> return -EINVAL;
> @@ -1083,10 +1083,15 @@ static int ocfs2_xattr_find_entry(struct inode *inode, int name_index,
> cmp = name_index - ocfs2_xattr_get_type(entry);
> if (!cmp)
> cmp = name_len - entry->xe_name_len;
> - if (!cmp)
> - cmp = memcmp(name, (xs->base +
> - le16_to_cpu(entry->xe_name_offset)),
> - name_len);
> + if (!cmp) {
> + name_offset = le16_to_cpu(entry->xe_name_offset);
> + if ((xs->base + name_offset + name_len) > xs->end) {
> + ocfs2_error(inode->i_sb,
> + "corrupted xattr entries");
> + return -EFSCORRUPTED;
> + }
> + cmp = memcmp(name, (xs->base + name_offset), name_len);
> + }
> if (cmp == 0)
> break;
> entry += 1;

\
 
 \ /
  Last update: 2024-05-27 18:30    [W:0.073 / U:1.168 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site