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Diffstat (limited to 'libxcb/src/xcb_auth.c')
-rw-r--r--libxcb/src/xcb_auth.c70
1 files changed, 61 insertions, 9 deletions
diff --git a/libxcb/src/xcb_auth.c b/libxcb/src/xcb_auth.c
index 00aad23c5..d774d1069 100644
--- a/libxcb/src/xcb_auth.c
+++ b/libxcb/src/xcb_auth.c
@@ -89,8 +89,7 @@ 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;
@@ -243,13 +242,55 @@ 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;
@@ -258,24 +299,30 @@ int _xcb_get_auth_info(int fd, xcb_auth_info_t *info, int display)
* for UNIX Domain Sockets, but this is irrelevant,
* since compute_auth() ignores the peer name in this
* case anyway.*/
- if (getpeername(fd, sockname, &socknamelen) == -1)
+ if ((sockname = get_peer_sock_name(getpeername, fd)) == NULL)
{
- if (getsockname(fd, sockname, &socknamelen) == -1)
+ if ((sockname = get_peer_sock_name(getsockname, fd)) == NULL)
return 0; /* can only authenticate sockets */
if (sockname->sa_family != AF_UNIX)
+ {
+ 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)
goto no_auth; /* out of memory */
- if (!gotsockname && getsockname(fd, sockname, &socknamelen) == -1)
+ if (!gotsockname && (sockname = get_peer_sock_name(getsockname, fd)) == NULL)
{
free(info->name);
goto no_auth; /* can only authenticate sockets */
@@ -288,10 +335,15 @@ int _xcb_get_auth_info(int fd, xcb_auth_info_t *info, int display)
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);