NFS: Fix filehandle bounds checking in nfs_fh_to_dentry()

[ Upstream commit ef93a685e01a281b5e2a25ce4e3428cf9371a205 ]

The function needs to check the minimal filehandle length before it can
access the embedded filehandle.

Reported-by: zhangjian <zhangjian496@huawei.com>
Fixes: 20fa190272 ("nfs: add export operations")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Trond Myklebust
2025-07-22 09:24:58 -04:00
committed by Greg Kroah-Hartman
parent 3b3d150889
commit cb09afa094

View File

@@ -67,14 +67,21 @@ nfs_fh_to_dentry(struct super_block *sb, struct fid *fid,
struct nfs4_label *label = NULL;
struct nfs_fattr *fattr = NULL;
struct nfs_fh *server_fh = nfs_exp_embedfh(fid->raw);
size_t fh_size = offsetof(struct nfs_fh, data) + server_fh->size;
size_t fh_size = offsetof(struct nfs_fh, data);
const struct nfs_rpc_ops *rpc_ops;
struct dentry *dentry;
struct inode *inode;
int len = EMBED_FH_OFF + XDR_QUADLEN(fh_size);
int len = EMBED_FH_OFF;
u32 *p = fid->raw;
int ret;
/* Initial check of bounds */
if (fh_len < len + XDR_QUADLEN(fh_size) ||
fh_len > XDR_QUADLEN(NFS_MAXFHSIZE))
return NULL;
/* Calculate embedded filehandle size */
fh_size += server_fh->size;
len += XDR_QUADLEN(fh_size);
/* NULL translates to ESTALE */
if (fh_len < len || fh_type != len)
return NULL;