X-Git-Url: http://git.demorecorder.com/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fxcb_auth.c;h=d774d106942bf46e157e91e73f995c4f9e274a63;hb=1c590d5a86ae854e53f388e40c952e92f11d59e6;hp=a648b16bc69d957f6b7113e2b67c2f9c7c6d0a93;hpb=9f24c91f91dd68a52e46191b686283b0df38d2f5;p=free-sw%2Fxcb%2Flibxcb

diff --git a/src/xcb_auth.c b/src/xcb_auth.c
index a648b16..d774d10 100644
--- a/src/xcb_auth.c
+++ b/src/xcb_auth.c
@@ -89,14 +89,14 @@ static int authname_match(enum auth_protos kind, char *name, size_t namelen)
 
 #define SIN6_ADDR(s) (&((struct sockaddr_in6 *)s)->sin6_addr)
 
-static Xauth *get_authptr(struct sockaddr *sockname, unsigned int socknamelen,
-                          int display)
+static Xauth *get_authptr(struct sockaddr *sockname, int display)
 {
     char *addr = 0;
     int addrlen = 0;
     unsigned short family;
     char hostnamebuf[256];   /* big enough for max hostname */
     char dispbuf[40];   /* big enough to hold more than 2^64 base 10 */
+    int dispbuflen;
 
     family = FamilyLocal; /* 256 */
     switch(sockname->sa_family)
@@ -127,7 +127,11 @@ static Xauth *get_authptr(struct sockaddr *sockname, unsigned int socknamelen,
         return 0;   /* cannot authenticate this family */
     }
 
-    snprintf(dispbuf, sizeof(dispbuf), "%d", display);
+    dispbuflen = snprintf(dispbuf, sizeof(dispbuf), "%d", display);
+    if(dispbuflen < 0)
+        return 0;
+    /* snprintf may have truncate our text */
+    dispbuflen = MIN(dispbuflen, sizeof(dispbuf) - 1);
 
     if (family == FamilyLocal) {
         if (gethostname(hostnamebuf, sizeof(hostnamebuf)) == -1)
@@ -138,7 +142,7 @@ static Xauth *get_authptr(struct sockaddr *sockname, unsigned int socknamelen,
 
     return XauGetBestAuthByAddr (family,
                                  (unsigned short) addrlen, addr,
-                                 (unsigned short) strlen(dispbuf), dispbuf,
+                                 (unsigned short) dispbuflen, dispbuf,
                                  N_AUTH_PROTOS, authnames, authnameslen);
 }
 
@@ -238,39 +242,110 @@ static int compute_auth(xcb_auth_info_t *info, Xauth *authptr, struct sockaddr *
     return 0;   /* Unknown authorization type */
 }
 
+/* `sockaddr_un.sun_path' typical size usually ranges between 92 and 108 */
+#define INITIAL_SOCKNAME_SLACK 108
+
+/* Return a dynamically allocated socket address structure according
+   to the value returned by either getpeername() or getsockname()
+   (according to POSIX, applications should not assume a particular
+   length for `sockaddr_un.sun_path') */
+static struct sockaddr *get_peer_sock_name(int (*socket_func)(int,
+							      struct sockaddr *,
+							      socklen_t *),
+					   int fd)
+{
+    socklen_t socknamelen = sizeof(struct sockaddr) + INITIAL_SOCKNAME_SLACK;
+    socklen_t actual_socknamelen = socknamelen;
+    struct sockaddr *sockname = malloc(socknamelen), *new_sockname = NULL;
+
+    if (sockname == NULL)
+        return NULL;
+
+    /* Both getpeername() and getsockname() truncates sockname if
+       there is not enough space and set the required length in
+       actual_socknamelen */
+    if (socket_func(fd, sockname, &actual_socknamelen) == -1)
+        goto sock_or_realloc_error;
+
+    if (actual_socknamelen > socknamelen)
+    {
+        socknamelen = actual_socknamelen;
+
+        if ((new_sockname = realloc(sockname, actual_socknamelen)) == NULL ||
+            socket_func(fd, new_sockname, &actual_socknamelen) == -1 ||
+            actual_socknamelen > socknamelen) 
+            goto sock_or_realloc_error;
+
+        sockname = new_sockname;
+    }
+
+    return sockname;
+
+ sock_or_realloc_error:
+    free(sockname);
+    return NULL;
+}
+
 int _xcb_get_auth_info(int fd, xcb_auth_info_t *info, int display)
 {
     /* code adapted from Xlib/ConnDis.c, xtrans/Xtranssocket.c,
        xtrans/Xtransutils.c */
-    char sockbuf[sizeof(struct sockaddr) + MAXPATHLEN];
-    unsigned int socknamelen = sizeof(sockbuf);   /* need extra space */
-    struct sockaddr *sockname = (struct sockaddr *) &sockbuf;
+    struct sockaddr *sockname = NULL;
+    int gotsockname = 0;
     Xauth *authptr = 0;
     int ret = 1;
 
-    if (getpeername(fd, sockname, &socknamelen) == -1)
+    /* Some systems like hpux or Hurd do not expose peer names
+     * for UNIX Domain Sockets, but this is irrelevant,
+     * since compute_auth() ignores the peer name in this
+     * case anyway.*/
+    if ((sockname = get_peer_sock_name(getpeername, fd)) == NULL)
     {
-        if (getsockname(fd, sockname, &socknamelen) == -1)
-            return 0;  /* can only authenticate sockets */
+        if ((sockname = get_peer_sock_name(getsockname, fd)) == NULL)
+            return 0;   /* can only authenticate sockets */
         if (sockname->sa_family != AF_UNIX)
-            return 0;
-        /* Some systems like hpux or Hurd do not expose peer names
-         * for UNIX Domain Sockets.  We do not need it anyway.  */
+        {
+            free(sockname);
+            return 0;   /* except for AF_UNIX, sockets should have peernames */
+        }
+        gotsockname = 1;
     }
 
-    authptr = get_authptr(sockname, socknamelen, display);
+    authptr = get_authptr(sockname, display);
     if (authptr == 0)
+    {
+        free(sockname);
         return 0;   /* cannot find good auth data */
+    }
 
     info->namelen = memdup(&info->name, authptr->name, authptr->name_length);
-    if(info->namelen)
-	ret = compute_auth(info, authptr, sockname);
+    if (!info->namelen)
+        goto no_auth;   /* out of memory */
+
+    if (!gotsockname && (sockname = get_peer_sock_name(getsockname, fd)) == NULL)
+    {
+        free(info->name);
+        goto no_auth;   /* can only authenticate sockets */
+    }
+
+    ret = compute_auth(info, authptr, sockname);
     if(!ret)
     {
-	free(info->name);
-	info->name = 0;
-	info->namelen = 0;
+        free(info->name);
+        goto no_auth;   /* cannot build auth record */
     }
+
+    free(sockname);
+    sockname = NULL;
+
     XauDisposeAuth(authptr);
     return ret;
+
+ no_auth:
+    free(sockname);
+
+    info->name = 0;
+    info->namelen = 0;
+    XauDisposeAuth(authptr);
+    return 0;
 }