| Message ID | 20240517094147.87133-2-mengferry@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | ocfs2: add checks in ocfs2_xattr_find_entry() to avoid potential out-of-bound access. | expand |
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 <mengferry@linux.alibaba.com> Reported-by: lei lu <llfamsec@gmail.com> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> > --- > 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,
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,
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 <mengferry@linux.alibaba.com> --- fs/ocfs2/xattr.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)