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
  12 #include "putty.h"
  13 #include "misc.h"
  14 #include "tree234.h"
  15 #include "puttymem.h"
  16
  17 #define GET_32BIT(cp) \
  18     (((unsigned long)(unsigned char)(cp)[0] << 24) | \
  19     ((unsigned long)(unsigned char)(cp)[1] << 16) | \
  20     ((unsigned long)(unsigned char)(cp)[2] << 8) | \
  21     ((unsigned long)(unsigned char)(cp)[3]))
  22
  23 int agent_exists(void)
  24 {
  25     if (getenv("SSH_AUTH_SOCK") != NULL)
  26         return TRUE;
  27     return FALSE;
  28 }
  29
  30 static tree234 *agent_connections;
  31 struct agent_connection {
  32     int fd;
  33     char *retbuf;
  34     char sizebuf[4];
  35     int retsize, retlen;
  36     void (*callback)(void *, void *, int);
  37     void *callback_ctx;
  38 };
  39 static int agent_conncmp(void *av, void *bv)
  40 {
  41     struct agent_connection *a = (struct agent_connection *) av;
  42     struct agent_connection *b = (struct agent_connection *) bv;
  43     if (a->fd < b->fd)
  44         return -1;
  45     if (a->fd > b->fd)
  46         return +1;
  47     return 0;
  48 }
  49 static int agent_connfind(void *av, void *bv)
  50 {
  51     int afd = *(int *) av;
  52     struct agent_connection *b = (struct agent_connection *) bv;
  53     if (afd < b->fd)
  54         return -1;
  55     if (afd > b->fd)
  56         return +1;
  57     return 0;
  58 }
  59
  60 static int agent_select_result(int fd, int event)
  61 {
  62     int ret;
  63     struct agent_connection *conn;
  64
  65     assert(event == 1);                /* not selecting for anything but R */
  66
  67     conn = find234(agent_connections, &fd, agent_connfind);
  68     if (!conn) {
  69         uxsel_del(fd);
  70         return 1;
  71     }
  72
  73     ret = read(fd, conn->retbuf+conn->retlen, conn->retsize-conn->retlen);
  74     if (ret <= 0) {
  75         if (conn->retbuf != conn->sizebuf) sfree(conn->retbuf);
  76         conn->retbuf = NULL;
  77         conn->retlen = 0;
  78         goto done;
  79     }
  80     conn->retlen += ret;
  81     if (conn->retsize == 4 && conn->retlen == 4) {
  82         conn->retsize = GET_32BIT(conn->retbuf);
  83         if (conn->retsize <= 0) {
  84             conn->retbuf = NULL;
  85             conn->retlen = 0;
  86             goto done;
  87         }
  88         conn->retsize += 4;
  89         assert(conn->retbuf == conn->sizebuf);
  90         conn->retbuf = snewn(conn->retsize, char);
  91         memcpy(conn->retbuf, conn->sizebuf, 4);
  92     }
  93
  94     if (conn->retlen < conn->retsize)
  95         return 0;                      /* more data to come */
  96
  97     done:
  98     /*
  99      * We have now completed the agent query. Do the callback, and
 100      * clean up. (Of course we don't free retbuf, since ownership
 101      * of that passes to the callback.)
 102      */
 103     conn->callback(conn->callback_ctx, conn->retbuf, conn->retlen);
 104     uxsel_del(fd);
 105     close(fd);
 106     del234(agent_connections, conn);
 107     sfree(conn);
 108     return 0;
 109 }
 110
 111 int agent_query(void *in, int inlen, void **out, int *outlen,
 112                 void (*callback)(void *, void *, int), void *callback_ctx)
 113 {
 114     char *name;
 115     int sock;
 116     struct sockaddr_un addr;
 117     int done;
 118     struct agent_connection *conn;
 119
 120     name = getenv("SSH_AUTH_SOCK");
 121     if (!name)
 122         goto failure;
 123
 124     sock = socket(PF_UNIX, SOCK_STREAM, 0);
 125     if (sock < 0) {
 126         perror("socket(PF_UNIX)");
 127         exit(1);
 128     }
 129
 130     addr.sun_family = AF_UNIX;
 131     strncpy(addr.sun_path, name, sizeof(addr.sun_path));
 132     if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
 133         close(sock);
 134         goto failure;
 135     }
 136
 137     for (done = 0; done < inlen ;) {
 138         int ret = write(sock, (char *)in + done, inlen - done);
 139         if (ret <= 0) {
 140             close(sock);
 141             goto failure;
 142         }
 143         done += ret;
 144     }
 145
 146     if (!agent_connections)
 147         agent_connections = newtree234(agent_conncmp);
 148
 149     conn = snew(struct agent_connection);
 150     conn->fd = sock;
 151     conn->retbuf = conn->sizebuf;
 152     conn->retsize = 4;
 153     conn->retlen = 0;
 154     conn->callback = callback;
 155     conn->callback_ctx = callback_ctx;
 156     add234(agent_connections, conn);
 157
 158     uxsel_set(sock, 1, agent_select_result);
 159     return 0;
 160
 161     failure:
 162     *out = NULL;
 163     *outlen = 0;
 164     return 1;
 165 }