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 <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/include/linux/sunrpc/gss_krb5.h b/include/linux/sunrpc/gss_krb5.h
index abfa1f32d914bff2e48315230e0b4ea807b4e1b0..01c5e43146320d73a065d51762de52d70176799b 100644 (file)
--- 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 17587163fcaef5484a57acf64879d1cce811be7f..bf5435db8785b2edc150df921114e47c4a14bb0f 100644 (file)
--- 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 f3f42a4465cfd1897d27447e4aafe5cd167054a2..f42e453e63eabac6a76e6f39ce74fdf3dc943344 100644 (file)
--- 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 63b06ee2d542050eff1233351454750203ad80a3..bf25f4d9acd136af476aae49f7a96776d5a034fa 100644 (file)
--- 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;