mdw@git.distorted.org.uk Git - sgt/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     const char *p = getenv("SSH_AUTH_SOCK");
  21     if (p && *p)
  22         return TRUE;
  23     return FALSE;
  24 }
  25
  26 static tree234 *agent_connections;
  27 struct agent_connection {
  28     int fd;
  29     char *retbuf;
  30     char sizebuf[4];
  31     int retsize, retlen;
  32     void (*callback)(void *, void *, int);
  33     void *callback_ctx;
  34 };
  35 static int agent_conncmp(void *av, void *bv)
  36 {
  37     struct agent_connection *a = (struct agent_connection *) av;
  38     struct agent_connection *b = (struct agent_connection *) bv;
  39     if (a->fd < b->fd)
  40         return -1;
  41     if (a->fd > b->fd)
  42         return +1;
  43     return 0;
  44 }
  45 static int agent_connfind(void *av, void *bv)
  46 {
  47     int afd = *(int *) av;
  48     struct agent_connection *b = (struct agent_connection *) bv;
  49     if (afd < b->fd)
  50         return -1;
  51     if (afd > b->fd)
  52         return +1;
  53     return 0;
  54 }
  55
  56 static int agent_select_result(int fd, int event)
  57 {
  58     int ret;
  59     struct agent_connection *conn;
  60
  61     assert(event == 1);                /* not selecting for anything but R */
  62
  63     conn = find234(agent_connections, &fd, agent_connfind);
  64     if (!conn) {
  65         uxsel_del(fd);
  66         return 1;
  67     }
  68
  69     ret = read(fd, conn->retbuf+conn->retlen, conn->retsize-conn->retlen);
  70     if (ret <= 0) {
  71         if (conn->retbuf != conn->sizebuf) sfree(conn->retbuf);
  72         conn->retbuf = NULL;
  73         conn->retlen = 0;
  74         goto done;
  75     }
  76     conn->retlen += ret;
  77     if (conn->retsize == 4 && conn->retlen == 4) {
  78         conn->retsize = GET_32BIT(conn->retbuf);
  79         if (conn->retsize <= 0) {
  80             conn->retbuf = NULL;
  81             conn->retlen = 0;
  82             goto done;
  83         }
  84         conn->retsize += 4;
  85         assert(conn->retbuf == conn->sizebuf);
  86         conn->retbuf = snewn(conn->retsize, char);
  87         memcpy(conn->retbuf, conn->sizebuf, 4);
  88     }
  89
  90     if (conn->retlen < conn->retsize)
  91         return 0;                      /* more data to come */
  92
  93     done:
  94     /*
  95      * We have now completed the agent query. Do the callback, and
  96      * clean up. (Of course we don't free retbuf, since ownership
  97      * of that passes to the callback.)
  98      */
  99     conn->callback(conn->callback_ctx, conn->retbuf, conn->retlen);
 100     uxsel_del(fd);
 101     close(fd);
 102     del234(agent_connections, conn);
 103     sfree(conn);
 104     return 0;
 105 }
 106
 107 int agent_query(void *in, int inlen, void **out, int *outlen,
 108                 void (*callback)(void *, void *, int), void *callback_ctx)
 109 {
 110     char *name;
 111     int sock;
 112     struct sockaddr_un addr;
 113     int done;
 114     struct agent_connection *conn;
 115
 116     name = getenv("SSH_AUTH_SOCK");
 117     if (!name)
 118         goto failure;
 119
 120     sock = socket(PF_UNIX, SOCK_STREAM, 0);
 121     if (sock < 0) {
 122         perror("socket(PF_UNIX)");
 123         exit(1);
 124     }
 125
 126     cloexec(sock);
 127
 128     addr.sun_family = AF_UNIX;
 129     strncpy(addr.sun_path, name, sizeof(addr.sun_path));
 130     if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
 131         close(sock);
 132         goto failure;
 133     }
 134
 135     for (done = 0; done < inlen ;) {
 136         int ret = write(sock, (char *)in + done, inlen - done);
 137         if (ret <= 0) {
 138             close(sock);
 139             goto failure;
 140         }
 141         done += ret;
 142     }
 143
 144     if (!agent_connections)
 145         agent_connections = newtree234(agent_conncmp);
 146
 147     conn = snew(struct agent_connection);
 148     conn->fd = sock;
 149     conn->retbuf = conn->sizebuf;
 150     conn->retsize = 4;
 151     conn->retlen = 0;
 152     conn->callback = callback;
 153     conn->callback_ctx = callback_ctx;
 154     add234(agent_connections, conn);
 155
 156     uxsel_set(sock, 1, agent_select_result);
 157     return 0;
 158
 159     failure:
 160     *out = NULL;
 161     *outlen = 0;
 162     return 1;
 163 }