git.distorted.org.uk Git - u/mdw/putty/blob - unix/uxagentc.c

   1 /*
   2  * SSH agent client code.
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <assert.h>
   8 #include <unistd.h>
   9 #include <sys/socket.h>
  10 #include <sys/un.h>
  11 #include <fcntl.h>
  12
  13 #include "putty.h"
  14 #include "misc.h"
  15 #include "tree234.h"
  16 #include "puttymem.h"
  17
  18 int agent_exists(void)
  19 {
  20     if (getenv("SSH_AUTH_SOCK") != NULL)
  21         return TRUE;
  22     return FALSE;
  23 }
  24
  25 static tree234 *agent_connections;
  26 struct agent_connection {
  27     int fd;
  28     char *retbuf;
  29     char sizebuf[4];
  30     int retsize, retlen;
  31     void (*callback)(void *, void *, int);
  32     void *callback_ctx;
  33 };
  34 static int agent_conncmp(void *av, void *bv)
  35 {
  36     struct agent_connection *a = (struct agent_connection *) av;
  37     struct agent_connection *b = (struct agent_connection *) bv;
  38     if (a->fd < b->fd)
  39         return -1;
  40     if (a->fd > b->fd)
  41         return +1;
  42     return 0;
  43 }
  44 static int agent_connfind(void *av, void *bv)
  45 {
  46     int afd = *(int *) av;
  47     struct agent_connection *b = (struct agent_connection *) bv;
  48     if (afd < b->fd)
  49         return -1;
  50     if (afd > b->fd)
  51         return +1;
  52     return 0;
  53 }
  54
  55 static int agent_select_result(int fd, int event)
  56 {
  57     int ret;
  58     struct agent_connection *conn;
  59
  60     assert(event == 1);                /* not selecting for anything but R */
  61
  62     conn = find234(agent_connections, &fd, agent_connfind);
  63     if (!conn) {
  64         uxsel_del(fd);
  65         return 1;
  66     }
  67
  68     ret = read(fd, conn->retbuf+conn->retlen, conn->retsize-conn->retlen);
  69     if (ret <= 0) {
  70         if (conn->retbuf != conn->sizebuf) sfree(conn->retbuf);
  71         conn->retbuf = NULL;
  72         conn->retlen = 0;
  73         goto done;
  74     }
  75     conn->retlen += ret;
  76     if (conn->retsize == 4 && conn->retlen == 4) {
  77         conn->retsize = GET_32BIT(conn->retbuf);
  78         if (conn->retsize <= 0) {
  79             conn->retbuf = NULL;
  80             conn->retlen = 0;
  81             goto done;
  82         }
  83         conn->retsize += 4;
  84         assert(conn->retbuf == conn->sizebuf);
  85         conn->retbuf = snewn(conn->retsize, char);
  86         memcpy(conn->retbuf, conn->sizebuf, 4);
  87     }
  88
  89     if (conn->retlen < conn->retsize)
  90         return 0;                      /* more data to come */
  91
  92     done:
  93     /*
  94      * We have now completed the agent query. Do the callback, and
  95      * clean up. (Of course we don't free retbuf, since ownership
  96      * of that passes to the callback.)
  97      */
  98     conn->callback(conn->callback_ctx, conn->retbuf, conn->retlen);
  99     uxsel_del(fd);
 100     close(fd);
 101     del234(agent_connections, conn);
 102     sfree(conn);
 103     return 0;
 104 }
 105
 106 int agent_query(void *in, int inlen, void **out, int *outlen,
 107                 void (*callback)(void *, void *, int), void *callback_ctx)
 108 {
 109     char *name;
 110     int sock;
 111     struct sockaddr_un addr;
 112     int done;
 113     struct agent_connection *conn;
 114
 115     name = getenv("SSH_AUTH_SOCK");
 116     if (!name)
 117         goto failure;
 118
 119     sock = socket(PF_UNIX, SOCK_STREAM, 0);
 120     if (sock < 0) {
 121         perror("socket(PF_UNIX)");
 122         exit(1);
 123     }
 124
 125     cloexec(sock);
 126
 127     addr.sun_family = AF_UNIX;
 128     strncpy(addr.sun_path, name, sizeof(addr.sun_path));
 129     if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
 130         close(sock);
 131         goto failure;
 132     }
 133
 134     for (done = 0; done < inlen ;) {
 135         int ret = write(sock, (char *)in + done, inlen - done);
 136         if (ret <= 0) {
 137             close(sock);
 138             goto failure;
 139         }
 140         done += ret;
 141     }
 142
 143     if (!agent_connections)
 144         agent_connections = newtree234(agent_conncmp);
 145
 146     conn = snew(struct agent_connection);
 147     conn->fd = sock;
 148     conn->retbuf = conn->sizebuf;
 149     conn->retsize = 4;
 150     conn->retlen = 0;
 151     conn->callback = callback;
 152     conn->callback_ctx = callback_ctx;
 153     add234(agent_connections, conn);
 154
 155     uxsel_set(sock, 1, agent_select_result);
 156     return 0;
 157
 158     failure:
 159     *out = NULL;
 160     *outlen = 0;
 161     return 1;
 162 }