SUNRPC,RPCSEC_GSS: remove unnecessary kmalloc of a checksum

Remove unnecessary kmalloc of temporary space to hold the md5 result; it's
small enough to just put on the stack.

This code may be called to process rpc's necessary to perform writes, so
there's a potential deadlock whenever we kmalloc() here.  After this a
couple kmalloc()'s still remain, to be removed soon.

This also fixes a rare double-free on error noticed by coverity.

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

5 files changed, 12 insertions, 17 deletions

diff --git a/net/sunrpc/auth_gss/gss_krb5_seal.c b/net/sunrpc/auth_gss/gss_krb5_seal.c
index d0dfdfd5e79e..58f9721980e2 100644
--- a/net/sunrpc/auth_gss/gss_krb5_seal.c
+++ b/net/sunrpc/auth_gss/gss_krb5_seal.c
@@ -76,7 +76,8 @@ gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
 {
         struct krb5_ctx         *ctx = gss_ctx->internal_ctx_id;
         s32                     checksum_type;
-        struct xdr_netobj       md5cksum = {.len = 0, .data = NULL};
+        char                    cksumdata[16];
+        struct xdr_netobj       md5cksum = {.len = 0, .data = cksumdata};
         unsigned char           *ptr, *krb5_hdr, *msg_start;
         s32                     now;
 
@@ -133,8 +134,6 @@ gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
                 BUG();
         }
 
-        kfree(md5cksum.data);
-
         if ((krb5_make_seq_num(ctx->seq, ctx->initiate ? 0 : 0xff,
                                ctx->seq_send, krb5_hdr + 16, krb5_hdr + 8)))
                 goto out_err;
@@ -143,6 +142,5 @@ gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
 
         return ((ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE);
 out_err:
-        kfree(md5cksum.data);
         return GSS_S_FAILURE;
 }
diff --git a/net/sunrpc/auth_gss/gss_krb5_unseal.c b/net/sunrpc/auth_gss/gss_krb5_unseal.c
index db055fd7d778..0828cf64100f 100644
--- a/net/sunrpc/auth_gss/gss_krb5_unseal.c
+++ b/net/sunrpc/auth_gss/gss_krb5_unseal.c
@@ -79,7 +79,8 @@ gss_verify_mic_kerberos(struct gss_ctx *gss_ctx,
         int                     signalg;
         int                     sealalg;
         s32                     checksum_type;
-        struct xdr_netobj       md5cksum = {.len = 0, .data = NULL};
+        char                    cksumdata[16];
+        struct xdr_netobj       md5cksum = {.len = 0, .data = cksumdata};
         s32                     now;
         int                     direction;
         s32                     seqnum;
@@ -176,6 +177,5 @@ gss_verify_mic_kerberos(struct gss_ctx *gss_ctx,
 
         ret = GSS_S_COMPLETE;
 out:
-        kfree(md5cksum.data);
         return ret;
 }
diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c
index af777cf9f251..346133e446cb 100644
--- a/net/sunrpc/auth_gss/gss_krb5_wrap.c
+++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c
@@ -121,7 +121,8 @@ gss_wrap_kerberos(struct gss_ctx *ctx, int offset,
 {
         struct krb5_ctx         *kctx = ctx->internal_ctx_id;
         s32                     checksum_type;
-        struct xdr_netobj       md5cksum = {.len = 0, .data = NULL};
+        char                    cksumdata[16];
+        struct xdr_netobj       md5cksum = {.len = 0, .data = cksumdata};
         int                     blocksize = 0, plainlen;
         unsigned char           *ptr, *krb5_hdr, *msg_start;
         s32                     now;
@@ -205,8 +206,6 @@ gss_wrap_kerberos(struct gss_ctx *ctx, int offset,
                 BUG();
         }
 
-        kfree(md5cksum.data);
-
         /* XXX would probably be more efficient to compute checksum
          * and encrypt at the same time: */
         if ((krb5_make_seq_num(kctx->seq, kctx->initiate ? 0 : 0xff,
@@ -221,7 +220,6 @@ gss_wrap_kerberos(struct gss_ctx *ctx, int offset,
 
         return ((kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE);
 out_err:
-        if (md5cksum.data) kfree(md5cksum.data);
         return GSS_S_FAILURE;
 }
 
@@ -232,7 +230,8 @@ gss_unwrap_kerberos(struct gss_ctx *ctx, int offset, struct xdr_buf *buf)
         int                     signalg;
         int                     sealalg;
         s32                     checksum_type;
-        struct xdr_netobj       md5cksum = {.len = 0, .data = NULL};
+        char                    cksumdata[16];
+        struct xdr_netobj       md5cksum = {.len = 0, .data = cksumdata};
         s32                     now;
         int                     direction;
         s32                     seqnum;
@@ -358,6 +357,5 @@ gss_unwrap_kerberos(struct gss_ctx *ctx, int offset, struct xdr_buf *buf)
 
         ret = GSS_S_COMPLETE;
 out:
-        if (md5cksum.data) kfree(md5cksum.data);
         return ret;
 }
diff --git a/net/sunrpc/auth_gss/gss_spkm3_seal.c b/net/sunrpc/auth_gss/gss_spkm3_seal.c
index 86fbf7c3e39c..18c7862bc234 100644
--- a/net/sunrpc/auth_gss/gss_spkm3_seal.c
+++ b/net/sunrpc/auth_gss/gss_spkm3_seal.c
@@ -57,7 +57,8 @@ spkm3_make_token(struct spkm3_ctx *ctx,
 {
         s32                     checksum_type;
         char                    tokhdrbuf[25];
-        struct xdr_netobj       md5cksum = {.len = 0, .data = NULL};
+        char                    cksumdata[16];
+        struct xdr_netobj       md5cksum = {.len = 0, .data = cksumdata};
         struct xdr_netobj       mic_hdr = {.len = 0, .data = tokhdrbuf};
         int                     tokenlen = 0;
         unsigned char           *ptr;
@@ -115,13 +116,11 @@ spkm3_make_token(struct spkm3_ctx *ctx,
                 dprintk("RPC: gss_spkm3_seal: SPKM_WRAP_TOK not supported\n");
                 goto out_err;
         }
-        kfree(md5cksum.data);
 
         /* XXX need to implement sequence numbers, and ctx->expired */
 
         return  GSS_S_COMPLETE;
 out_err:
-        kfree(md5cksum.data);
         token->data = NULL;
         token->len = 0;
         return GSS_S_FAILURE;
diff --git a/net/sunrpc/auth_gss/gss_spkm3_unseal.c b/net/sunrpc/auth_gss/gss_spkm3_unseal.c
index 96851b0ba1ba..8537f581ef9b 100644
--- a/net/sunrpc/auth_gss/gss_spkm3_unseal.c
+++ b/net/sunrpc/auth_gss/gss_spkm3_unseal.c
@@ -56,7 +56,8 @@ spkm3_read_token(struct spkm3_ctx *ctx,
 {
         s32                     code;
         struct xdr_netobj       wire_cksum = {.len =0, .data = NULL};
-        struct xdr_netobj       md5cksum = {.len = 0, .data = NULL};
+        char                    cksumdata[16];
+        struct xdr_netobj       md5cksum = {.len = 0, .data = cksumdata};
         unsigned char           *ptr = (unsigned char *)read_token->data;
         unsigned char           *cksum;
         int                     bodysize, md5elen;
@@ -120,7 +121,6 @@ spkm3_read_token(struct spkm3_ctx *ctx,
         /* XXX: need to add expiration and sequencing */
         ret = GSS_S_COMPLETE;
 out:
-        kfree(md5cksum.data);
         kfree(wire_cksum.data);
         return ret;
 }