From d922a84a8bf1d627810906d033223d4fa629fdbf Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 4 Dec 2006 20:22:40 -0500 Subject: [PATCH] rpcgss: krb5: sanity check sealalg value in the downcall The sealalg is checked in several places, giving the impression it could be either SEAL_ALG_NONE or SEAL_ALG_DES. But in fact SEAL_ALG_NONE seems to be sufficient only for making mic's, and all the contexts we get must be capable of wrapping as well. So the sealalg must be SEAL_ALG_DES. As with signalg, just check for the right value on the downcall and ignore it otherwise. Similarly, tighten expectations for the sealalg on incoming tokens, in case we do support other values eventually. Signed-off-by: J. Bruce Fields Signed-off-by: Trond Myklebust --- include/linux/sunrpc/gss_krb5.h | 1 - net/sunrpc/auth_gss/gss_krb5_mech.c | 4 +++- net/sunrpc/auth_gss/gss_krb5_seal.c | 6 ------ net/sunrpc/auth_gss/gss_krb5_wrap.c | 25 ++----------------------- 4 files changed, 5 insertions(+), 31 deletions(-) diff --git a/include/linux/sunrpc/gss_krb5.h b/include/linux/sunrpc/gss_krb5.h index abfa1f32d914..01c5e4314632 100644 --- a/include/linux/sunrpc/gss_krb5.h +++ b/include/linux/sunrpc/gss_krb5.h @@ -44,7 +44,6 @@ struct krb5_ctx { int initiate; /* 1 = initiating, 0 = accepting */ int seed_init; unsigned char seed[16]; - int sealalg; struct crypto_blkcipher *enc; struct crypto_blkcipher *seq; s32 endtime; diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c index 17587163fcae..bf5435db8785 100644 --- a/net/sunrpc/auth_gss/gss_krb5_mech.c +++ b/net/sunrpc/auth_gss/gss_krb5_mech.c @@ -148,9 +148,11 @@ gss_import_sec_context_kerberos(const void *p, goto out_err_free_ctx; if (tmp != SGN_ALG_DES_MAC_MD5) goto out_err_free_ctx; - p = simple_get_bytes(p, end, &ctx->sealalg, sizeof(ctx->sealalg)); + p = simple_get_bytes(p, end, &tmp, sizeof(tmp)); if (IS_ERR(p)) goto out_err_free_ctx; + if (tmp != SEAL_ALG_DES) + goto out_err_free_ctx; p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime)); if (IS_ERR(p)) goto out_err_free_ctx; diff --git a/net/sunrpc/auth_gss/gss_krb5_seal.c b/net/sunrpc/auth_gss/gss_krb5_seal.c index f3f42a4465cf..f42e453e63ea 100644 --- a/net/sunrpc/auth_gss/gss_krb5_seal.c +++ b/net/sunrpc/auth_gss/gss_krb5_seal.c @@ -87,12 +87,6 @@ gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text, now = get_seconds(); - if (ctx->sealalg != SEAL_ALG_NONE && ctx->sealalg != SEAL_ALG_DES) { - dprintk("RPC: gss_krb5_seal: ctx->sealalg %d not supported\n", - ctx->sealalg); - return GSS_S_FAILURE; - } - token->len = g_token_size(&ctx->mech_used, 22); ptr = token->data; diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c index 63b06ee2d542..bf25f4d9acd1 100644 --- a/net/sunrpc/auth_gss/gss_krb5_wrap.c +++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c @@ -133,12 +133,6 @@ gss_wrap_kerberos(struct gss_ctx *ctx, int offset, now = get_seconds(); - if (kctx->sealalg != SEAL_ALG_NONE && kctx->sealalg != SEAL_ALG_DES) { - dprintk("RPC: gss_krb5_seal: kctx->sealalg %d not supported\n", - kctx->sealalg); - return GSS_S_FAILURE; - } - blocksize = crypto_blkcipher_blocksize(kctx->enc); gss_krb5_add_padding(buf, offset, blocksize); BUG_ON((buf->len - offset) % blocksize); @@ -169,7 +163,7 @@ gss_wrap_kerberos(struct gss_ctx *ctx, int offset, *(__be16 *)(krb5_hdr + 2) = htons(SGN_ALG_DES_MAC_MD5); memset(krb5_hdr + 4, 0xff, 4); - *(__be16 *)(krb5_hdr + 4) = htons(kctx->sealalg); + *(__be16 *)(krb5_hdr + 4) = htons(SEAL_ALG_DES); make_confounder(msg_start, blocksize); @@ -245,26 +239,11 @@ gss_unwrap_kerberos(struct gss_ctx *ctx, int offset, struct xdr_buf *buf) if ((ptr[4] != 0xff) || (ptr[5] != 0xff)) return GSS_S_DEFECTIVE_TOKEN; - if (sealalg == 0xffff) + if (sealalg != SEAL_ALG_DES) return GSS_S_DEFECTIVE_TOKEN; if (signalg != SGN_ALG_DES_MAC_MD5) return GSS_S_DEFECTIVE_TOKEN; - /* in the current spec, there is only one valid seal algorithm per - key type, so a simple comparison is ok */ - - if (sealalg != kctx->sealalg) - return GSS_S_DEFECTIVE_TOKEN; - - /* there are several mappings of seal algorithms to sign algorithms, - but few enough that we can try them all. */ - - if ((kctx->sealalg == SEAL_ALG_NONE && signalg > 1) || - (kctx->sealalg == SEAL_ALG_1 && signalg != SGN_ALG_3) || - (kctx->sealalg == SEAL_ALG_DES3KD && - signalg != SGN_ALG_HMAC_SHA1_DES3_KD)) - return GSS_S_DEFECTIVE_TOKEN; - if (gss_decrypt_xdr_buf(kctx->enc, buf, ptr + 22 - (unsigned char *)buf->head[0].iov_base)) return GSS_S_DEFECTIVE_TOKEN;