Page MenuHomeFreeBSD
Files F167133067

D58792.id183959.diff
No OneTemporary
Actions

D58792.id183959.diff
View Options

diff --git a/sys/kern/uipc_usrreq.c b/sys/kern/uipc_usrreq.c
--- a/sys/kern/uipc_usrreq.c
+++ b/sys/kern/uipc_usrreq.c
@@ -3115,7 +3115,7 @@
* fallback; if not, it may be an O_PATH handle for a bound socket's
* vnode, so fall through to an EMPTYPATH lookup.
*/
- if (*buf == '\0') {
+ if (*buf == '\0' && fd != AT_FDCWD) {
error = unp_socket_fd_peer(td, fd, so2p);
if (error != ENOTSOCK)
return (error);
diff --git a/tests/sys/kern/unix_connectat.c b/tests/sys/kern/unix_connectat.c
--- a/tests/sys/kern/unix_connectat.c
+++ b/tests/sys/kern/unix_connectat.c
@@ -78,6 +78,13 @@
.sun_len = offsetof(struct sockaddr_un, sun_path),
};
+/* A nonempty address whose path starts with NUL, as Linux abstract names do. */
+static const struct sockaddr_un nul_sun = {
+ .sun_family = AF_UNIX,
+ .sun_len = offsetof(struct sockaddr_un, sun_path) + 2,
+ .sun_path = "\0x",
+};
+
/* Make a bound, listening stream socket. */
static int
mklistener(const char *path)
@@ -657,6 +664,32 @@
ATF_REQUIRE_EQ(0, close(s));
}
+/*
+ * A NUL-leading path with a nonzero length is not the empty-path
+ * extension: connect(2) and connectat(2) with AT_FDCWD must perform a
+ * pathname lookup and fail with ENOENT, not treat AT_FDCWD as a peer
+ * descriptor and fail with EBADF.
+ *
+ * Such addresses occur in the wild: they name Linux abstract namespace
+ * sockets, and the linuxulator passes them through with the leading NUL
+ * intact. libxcb tries the abstract X11 socket first and falls back to
+ * the pathname socket only on ENOENT or ECONNREFUSED, so when connect(2)
+ * briefly returned EBADF here, every Linux X11 client on the linuxulator
+ * failed at startup with "Missing X server or $DISPLAY".
+ */
+ATF_TC_WITHOUT_HEAD(nul_path_at_fdcwd);
+ATF_TC_BODY(nul_path_at_fdcwd, tc)
+{
+ int s;
+
+ ATF_REQUIRE((s = socket(PF_UNIX, SOCK_STREAM, 0)) >= 0);
+ ATF_REQUIRE_ERRNO(ENOENT, connect(s,
+ (const struct sockaddr *)&nul_sun, nul_sun.sun_len) == -1);
+ ATF_REQUIRE_ERRNO(ENOENT, connectat(AT_FDCWD, s,
+ (const struct sockaddr *)&nul_sun, nul_sun.sun_len) == -1);
+ ATF_REQUIRE_EQ(0, close(s));
+}
+
/* Error matrix for unsuitable descriptors and peers. */
ATF_TC_WITHOUT_HEAD(bad_peers);
ATF_TC_BODY(bad_peers, tc)
@@ -763,6 +796,7 @@
ATF_TP_ADD_TC(tp, devfd_mode_rdlnk);
ATF_TP_ADD_TC(tp, devfd_mode_nodup_rdlnk);
ATF_TP_ADD_TC(tp, empty_path_at_fdcwd);
+ ATF_TP_ADD_TC(tp, nul_path_at_fdcwd);
ATF_TP_ADD_TC(tp, bad_peers);
ATF_TP_ADD_TC(tp, cap_connectat);
ATF_TP_ADD_TC(tp, cap_connectat_denied);

File Metadata

Mime Type
text/plain
Expires
Thu, Aug 20, 9:05 AM (1 h, 45 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
36906855
Default Alt Text
D58792.id183959.diff (2 KB)

Event Timeline