From: Chuck Lever chuck.lever@oracle.com
[ Upstream commit a7e429a6fa6d612d1dacde96c885dc1bb4a9f400 ]
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: 35e77d21baa0 ("SUNRPC: Add rpc_auth::au_ralign field") Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/sunrpc/gss_api.h | 1 + net/sunrpc/auth_gss/auth_gss.c | 8 +++----- net/sunrpc/auth_gss/gss_krb5_wrap.c | 19 +++++++++++++++---- 3 files changed, 19 insertions(+), 9 deletions(-)
diff --git a/include/linux/sunrpc/gss_api.h b/include/linux/sunrpc/gss_api.h index e9a79518d6527..bc07e51f20d1c 100644 --- a/include/linux/sunrpc/gss_api.h +++ b/include/linux/sunrpc/gss_api.h @@ -21,6 +21,7 @@ struct gss_ctx { struct gss_api_mech *mech_type; void *internal_ctx_id; + unsigned int slack, align; };
#define GSS_C_NO_BUFFER ((struct xdr_netobj) 0) diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c index a08a733f2d7c2..a7ad150fd4ee9 100644 --- a/net/sunrpc/auth_gss/auth_gss.c +++ b/net/sunrpc/auth_gss/auth_gss.c @@ -2030,7 +2030,6 @@ gss_unwrap_resp_priv(struct rpc_task *task, struct rpc_cred *cred, struct xdr_buf *rcv_buf = &rqstp->rq_rcv_buf; struct kvec *head = rqstp->rq_rcv_buf.head; struct rpc_auth *auth = cred->cr_auth; - unsigned int savedlen = rcv_buf->len; u32 offset, opaque_len, maj_stat; __be32 *p;
@@ -2057,10 +2056,9 @@ gss_unwrap_resp_priv(struct rpc_task *task, struct rpc_cred *cred, */ xdr_init_decode(xdr, rcv_buf, p, rqstp);
- auth->au_rslack = auth->au_verfsize + 2 + - XDR_QUADLEN(savedlen - rcv_buf->len); - auth->au_ralign = auth->au_verfsize + 2 + - XDR_QUADLEN(savedlen - rcv_buf->len); + auth->au_rslack = auth->au_verfsize + 2 + ctx->gc_gss_ctx->slack; + auth->au_ralign = auth->au_verfsize + 2 + ctx->gc_gss_ctx->align; + return 0; unwrap_failed: trace_rpcgss_unwrap_failed(task); diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c index c7589e35d5d92..4905652e75679 100644 --- a/net/sunrpc/auth_gss/gss_krb5_wrap.c +++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c @@ -262,7 +262,8 @@ gss_wrap_kerberos_v1(struct krb5_ctx *kctx, int offset,
static u32 gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, int len, - struct xdr_buf *buf) + struct xdr_buf *buf, unsigned int *slack, + unsigned int *align) { int signalg; int sealalg; @@ -280,6 +281,7 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, int len, u32 conflen = kctx->gk5e->conflen; int crypt_offset; u8 *cksumkey; + unsigned int saved_len = buf->len;
dprintk("RPC: gss_unwrap_kerberos\n");
@@ -383,6 +385,10 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, int len, if (gss_krb5_remove_padding(buf, blocksize)) return GSS_S_DEFECTIVE_TOKEN;
+ /* slack must include room for krb5 padding */ + *slack = XDR_QUADLEN(saved_len - buf->len); + /* The GSS blob always precedes the RPC message payload */ + *align = *slack; return GSS_S_COMPLETE; }
@@ -489,7 +495,8 @@ gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset,
static u32 gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, int len, - struct xdr_buf *buf) + struct xdr_buf *buf, unsigned int *slack, + unsigned int *align) { time64_t now; u8 *ptr; @@ -583,6 +590,8 @@ gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, int len, /* Trim off the trailing "extra count" and checksum blob */ buf->len -= ec + GSS_KRB5_TOK_HDR_LEN + tailskip;
+ *align = XDR_QUADLEN(GSS_KRB5_TOK_HDR_LEN + headskip); + *slack = *align + XDR_QUADLEN(ec + GSS_KRB5_TOK_HDR_LEN + tailskip); return GSS_S_COMPLETE; }
@@ -617,9 +626,11 @@ gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, case ENCTYPE_DES_CBC_RAW: case ENCTYPE_DES3_CBC_RAW: case ENCTYPE_ARCFOUR_HMAC: - return gss_unwrap_kerberos_v1(kctx, offset, len, buf); + return gss_unwrap_kerberos_v1(kctx, offset, len, buf, + &gctx->slack, &gctx->align); case ENCTYPE_AES128_CTS_HMAC_SHA1_96: case ENCTYPE_AES256_CTS_HMAC_SHA1_96: - return gss_unwrap_kerberos_v2(kctx, offset, len, buf); + return gss_unwrap_kerberos_v2(kctx, offset, len, buf, + &gctx->slack, &gctx->align); } }