From: J. Bruce Fields Date: Fri, 5 May 2017 20:17:57 +0000 (-0400) Subject: nfsd: encoders mustn't use unitialized values in error cases X-Git-Tag: release-20171130_firefly~4^2~100^2~1^2~7^2~2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=52cf24769487de7100d824e8c12ecc310de841d7;p=firefly-linux-kernel-4.4.55.git nfsd: encoders mustn't use unitialized values in error cases commit f961e3f2acae94b727380c0b74e2d3954d0edf79 upstream. In error cases, lgp->lg_layout_type may be out of bounds; so we shouldn't be using it until after the check of nfserr. This was seen to crash nfsd threads when the server receives a LAYOUTGET request with a large layout type. GETDEVICEINFO has the same problem. Reported-by: Ari Kauppi Reviewed-by: Christoph Hellwig Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index 12935209deca..c3e1cb481fe0 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -4041,8 +4041,7 @@ nfsd4_encode_getdeviceinfo(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_getdeviceinfo *gdev) { struct xdr_stream *xdr = &resp->xdr; - const struct nfsd4_layout_ops *ops = - nfsd4_layout_ops[gdev->gd_layout_type]; + const struct nfsd4_layout_ops *ops; u32 starting_len = xdr->buf->len, needed_len; __be32 *p; @@ -4059,6 +4058,7 @@ nfsd4_encode_getdeviceinfo(struct nfsd4_compoundres *resp, __be32 nfserr, /* If maxcount is 0 then just update notifications */ if (gdev->gd_maxcount != 0) { + ops = nfsd4_layout_ops[gdev->gd_layout_type]; nfserr = ops->encode_getdeviceinfo(xdr, gdev); if (nfserr) { /* @@ -4111,8 +4111,7 @@ nfsd4_encode_layoutget(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_layoutget *lgp) { struct xdr_stream *xdr = &resp->xdr; - const struct nfsd4_layout_ops *ops = - nfsd4_layout_ops[lgp->lg_layout_type]; + const struct nfsd4_layout_ops *ops; __be32 *p; dprintk("%s: err %d\n", __func__, nfserr); @@ -4135,6 +4134,7 @@ nfsd4_encode_layoutget(struct nfsd4_compoundres *resp, __be32 nfserr, *p++ = cpu_to_be32(lgp->lg_seg.iomode); *p++ = cpu_to_be32(lgp->lg_layout_type); + ops = nfsd4_layout_ops[lgp->lg_layout_type]; nfserr = ops->encode_layoutget(xdr, lgp); out: kfree(lgp->lg_content);