From: Trond Myklebust Date: Tue, 22 Jul 2025 13:24:58 +0000 (-0400) Subject: NFS: Fix filehandle bounds checking in nfs_fh_to_dentry() X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=ef93a685e01a281b5e2a25ce4e3428cf9371a205;p=linux-block.git NFS: Fix filehandle bounds checking in nfs_fh_to_dentry() The function needs to check the minimal filehandle length before it can access the embedded filehandle. Reported-by: zhangjian Fixes: 20fa19027286 ("nfs: add export operations") Signed-off-by: Trond Myklebust --- diff --git a/fs/nfs/export.c b/fs/nfs/export.c index e9c233b6fd20..a10dd5f9d078 100644 --- a/fs/nfs/export.c +++ b/fs/nfs/export.c @@ -66,14 +66,21 @@ nfs_fh_to_dentry(struct super_block *sb, struct fid *fid, { 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;