1 files changed, 109 insertions, 0 deletions

diff --git a/net/rxrpc/ar-key.c b/net/rxrpc/ar-key.c
index a3a7acb5071a..bf4d623ee1ce 100644
--- a/net/rxrpc/ar-key.c
+++ b/net/rxrpc/ar-key.c
@@ -29,6 +29,7 @@ static int rxrpc_instantiate_s(struct key *, const void *, size_t);
 static void rxrpc_destroy(struct key *);
 static void rxrpc_destroy_s(struct key *);
 static void rxrpc_describe(const struct key *, struct seq_file *);
+static long rxrpc_read(const struct key *, char __user *, size_t);
 
 /*
  * rxrpc defined keys take an arbitrary string as the description and an
@@ -40,6 +41,7 @@ struct key_type key_type_rxrpc = {
         .match          = user_match,
         .destroy        = rxrpc_destroy,
         .describe       = rxrpc_describe,
+        .read           = rxrpc_read,
 };
 EXPORT_SYMBOL(key_type_rxrpc);
 
@@ -592,3 +594,110 @@ struct key *rxrpc_get_null_key(const char *keyname)
         return key;
 }
 EXPORT_SYMBOL(rxrpc_get_null_key);
+
+/*
+ * read the contents of an rxrpc key
+ * - this returns the result in XDR form
+ */
+static long rxrpc_read(const struct key *key,
+                       char __user *buffer, size_t buflen)
+{
+        struct rxrpc_key_token *token;
+        size_t size, toksize;
+        __be32 __user *xdr;
+        u32 cnlen, tktlen, ntoks, zero;
+
+        _enter("");
+
+        /* we don't know what form we should return non-AFS keys in */
+        if (memcmp(key->description, "afs@", 4) != 0)
+                return -EOPNOTSUPP;
+        cnlen = strlen(key->description + 4);
+
+        /* AFS keys we return in XDR form, so we need to work out the size of
+         * the XDR */
+        size = 2 * 4;   /* flags, cellname len */
+        size += (cnlen + 3) & ~3;       /* cellname */
+        size += 1 * 4;  /* token count */
+
+        ntoks = 0;
+        for (token = key->payload.data; token; token = token->next) {
+                switch (token->security_index) {
+                case RXRPC_SECURITY_RXKAD:
+                        size += 2 * 4;  /* length, security index (switch ID) */
+                        size += 8 * 4;  /* viceid, kvno, key*2, begin, end,
+                                         * primary, tktlen */
+                        size += (token->kad->ticket_len + 3) & ~3; /* ticket */
+                        ntoks++;
+                        break;
+
+                default: /* can't encode */
+                        break;
+                }
+        }
+
+        if (!buffer || buflen < size)
+                return size;
+
+        xdr = (__be32 __user *) buffer;
+        zero = 0;
+#define ENCODE(x)                               \
+        do {                                    \
+                __be32 y = htonl(x);            \
+                if (put_user(y, xdr++) < 0)     \
+                        goto fault;             \
+        } while(0)
+
+        ENCODE(0);      /* flags */
+        ENCODE(cnlen);  /* cellname length */
+        if (copy_to_user(xdr, key->description + 4, cnlen) != 0)
+                goto fault;
+        if (cnlen & 3 &&
+            copy_to_user((u8 *)xdr + cnlen, &zero, 4 - (cnlen & 3)) != 0)
+                goto fault;
+        xdr += (cnlen + 3) >> 2;
+        ENCODE(ntoks);  /* token count */
+
+        for (token = key->payload.data; token; token = token->next) {
+                toksize = 1 * 4;        /* sec index */
+
+                switch (token->security_index) {
+                case RXRPC_SECURITY_RXKAD:
+                        toksize += 8 * 4;
+                        toksize += (token->kad->ticket_len + 3) & ~3;
+                        ENCODE(toksize);
+                        ENCODE(token->security_index);
+                        ENCODE(token->kad->vice_id);
+                        ENCODE(token->kad->kvno);
+                        if (copy_to_user(xdr, token->kad->session_key, 8) != 0)
+                                goto fault;
+                        xdr += 8 >> 2;
+                        ENCODE(token->kad->start);
+                        ENCODE(token->kad->expiry);
+                        ENCODE(token->kad->primary_flag);
+                        tktlen = token->kad->ticket_len;
+                        ENCODE(tktlen);
+                        if (copy_to_user(xdr, token->kad->ticket, tktlen) != 0)
+                                goto fault;
+                        if (tktlen & 3 &&
+                            copy_to_user((u8 *)xdr + tktlen, &zero,
+                                         4 - (tktlen & 3)) != 0)
+                                goto fault;
+                        xdr += (tktlen + 3) >> 2;
+                        break;
+
+                default:
+                        break;
+                }
+        }
+
+#undef ENCODE
+
+        ASSERTCMP((char __user *) xdr - buffer, ==, size);
+        _leave(" = %zu", size);
+        return size;
+
+fault:
+        _leave(" = -EFAULT");
+        return -EFAULT;
+}