From: J. Bruce Fields Date: Fri, 2 Jul 2021 00:06:56 +0000 (-0400) Subject: nfsd: fix NULL dereference in nfs3svc_encode_getaclres X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ab1016d39cc052064e32f25ad18ef8767a0ee3b8;p=linux.git nfsd: fix NULL dereference in nfs3svc_encode_getaclres In error cases the dentry may be NULL. Before 20798dfe249a, the encoder also checked dentry and d_really_is_positive(dentry), but that looks like overkill to me--zero status should be enough to guarantee a positive dentry. This isn't the first time we've seen an error-case NULL dereference hidden in the initialization of a local variable in an xdr encoder. But I went back through the other recent rewrites and didn't spot any similar bugs. Reported-by: JianHong Yin Reviewed-by: Chuck Lever III Fixes: 20798dfe249a ("NFSD: Update the NFSv3 GETACL result encoder...") Signed-off-by: J. Bruce Fields --- diff --git a/fs/nfsd/nfs3acl.c b/fs/nfsd/nfs3acl.c index a1591feeea22c..5dfe7644a5172 100644 --- a/fs/nfsd/nfs3acl.c +++ b/fs/nfsd/nfs3acl.c @@ -172,7 +172,7 @@ static int nfs3svc_encode_getaclres(struct svc_rqst *rqstp, __be32 *p) struct nfsd3_getaclres *resp = rqstp->rq_resp; struct dentry *dentry = resp->fh.fh_dentry; struct kvec *head = rqstp->rq_res.head; - struct inode *inode = d_inode(dentry); + struct inode *inode; unsigned int base; int n; int w; @@ -181,6 +181,7 @@ static int nfs3svc_encode_getaclres(struct svc_rqst *rqstp, __be32 *p) return 0; switch (resp->status) { case nfs_ok: + inode = d_inode(dentry); if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh)) return 0; if (xdr_stream_encode_u32(xdr, resp->mask) < 0)