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SUNRPC: Fix GSS privacy computation of auth->au_ralign
When the au_ralign field was added to gss_unwrap_resp_priv, the
wrong calculation was used. Setting au_rslack == au_ralign is
probably correct for kerberos_v1 privacy, but kerberos_v2 privacy
adds additional GSS data after the clear text RPC message.
au_ralign needs to be smaller than au_rslack in that fairly common
case.
When xdr_buf_trim() is restored to gss_unwrap_kerberos_v2(), it does
exactly what I feared it would: it trims off part of the clear text
RPC message. However, that's because rpc_prepare_reply_pages() does
not set up the rq_rcv_buf's tail correctly because au_ralign is too
large.
Fixing the au_ralign computation also corrects the alignment of
rq_rcv_buf->pages so that the client does not have to shift reply
data payloads after they are received.
Fixes: 35e77d21ba
("SUNRPC: Add rpc_auth::au_ralign field")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
parent
31c9590ae4
commit
a7e429a6fa
3 changed files with 19 additions and 9 deletions
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@ -21,6 +21,7 @@
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struct gss_ctx {
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struct gss_api_mech *mech_type;
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void *internal_ctx_id;
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unsigned int slack, align;
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};
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#define GSS_C_NO_BUFFER ((struct xdr_netobj) 0)
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@ -2032,7 +2032,6 @@ gss_unwrap_resp_priv(struct rpc_task *task, struct rpc_cred *cred,
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struct xdr_buf *rcv_buf = &rqstp->rq_rcv_buf;
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struct kvec *head = rqstp->rq_rcv_buf.head;
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struct rpc_auth *auth = cred->cr_auth;
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unsigned int savedlen = rcv_buf->len;
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u32 offset, opaque_len, maj_stat;
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__be32 *p;
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@ -2059,10 +2058,9 @@ gss_unwrap_resp_priv(struct rpc_task *task, struct rpc_cred *cred,
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*/
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xdr_init_decode(xdr, rcv_buf, p, rqstp);
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auth->au_rslack = auth->au_verfsize + 2 +
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XDR_QUADLEN(savedlen - rcv_buf->len);
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auth->au_ralign = auth->au_verfsize + 2 +
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XDR_QUADLEN(savedlen - rcv_buf->len);
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auth->au_rslack = auth->au_verfsize + 2 + ctx->gc_gss_ctx->slack;
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auth->au_ralign = auth->au_verfsize + 2 + ctx->gc_gss_ctx->align;
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return 0;
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unwrap_failed:
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trace_rpcgss_unwrap_failed(task);
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@ -262,7 +262,8 @@ gss_wrap_kerberos_v1(struct krb5_ctx *kctx, int offset,
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static u32
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gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, int len,
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struct xdr_buf *buf)
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struct xdr_buf *buf, unsigned int *slack,
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unsigned int *align)
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{
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int signalg;
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int sealalg;
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@ -280,6 +281,7 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, int len,
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u32 conflen = kctx->gk5e->conflen;
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int crypt_offset;
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u8 *cksumkey;
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unsigned int saved_len = buf->len;
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dprintk("RPC: gss_unwrap_kerberos\n");
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@ -383,6 +385,10 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, int len,
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if (gss_krb5_remove_padding(buf, blocksize))
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return GSS_S_DEFECTIVE_TOKEN;
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/* slack must include room for krb5 padding */
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*slack = XDR_QUADLEN(saved_len - buf->len);
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/* The GSS blob always precedes the RPC message payload */
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*align = *slack;
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return GSS_S_COMPLETE;
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}
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@ -489,7 +495,8 @@ gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset,
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static u32
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gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, int len,
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struct xdr_buf *buf)
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struct xdr_buf *buf, unsigned int *slack,
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unsigned int *align)
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{
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time64_t now;
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u8 *ptr;
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@ -583,6 +590,8 @@ gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, int len,
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/* Trim off the trailing "extra count" and checksum blob */
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buf->len -= ec + GSS_KRB5_TOK_HDR_LEN + tailskip;
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*align = XDR_QUADLEN(GSS_KRB5_TOK_HDR_LEN + headskip);
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*slack = *align + XDR_QUADLEN(ec + GSS_KRB5_TOK_HDR_LEN + tailskip);
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return GSS_S_COMPLETE;
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}
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@ -617,9 +626,11 @@ gss_unwrap_kerberos(struct gss_ctx *gctx, int offset,
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case ENCTYPE_DES_CBC_RAW:
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case ENCTYPE_DES3_CBC_RAW:
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case ENCTYPE_ARCFOUR_HMAC:
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return gss_unwrap_kerberos_v1(kctx, offset, len, buf);
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return gss_unwrap_kerberos_v1(kctx, offset, len, buf,
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&gctx->slack, &gctx->align);
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case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
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case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
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return gss_unwrap_kerberos_v2(kctx, offset, len, buf);
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return gss_unwrap_kerberos_v2(kctx, offset, len, buf,
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&gctx->slack, &gctx->align);
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}
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}
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