5.10-stable review patch. If anyone has any objections, please let me know.
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From: J. Bruce Fields bfields@redhat.com
[ Upstream commit ab1016d39cc052064e32f25ad18ef8767a0ee3b8 ]
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 jiyin@redhat.com Reviewed-by: Chuck Lever III chuck.lever@oracle.com Fixes: 20798dfe249a ("NFSD: Update the NFSv3 GETACL result encoder...") Signed-off-by: J. Bruce Fields bfields@redhat.com Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/nfs3acl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/nfsd/nfs3acl.c b/fs/nfsd/nfs3acl.c index cfb686f23e571..5e13e5f7f92b8 100644 --- a/fs/nfsd/nfs3acl.c +++ b/fs/nfsd/nfs3acl.c @@ -170,7 +170,7 @@ 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; @@ -179,6 +179,7 @@ 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)