From: Maxim Dounin <mdounin@mdounin.ru>
Date: Wed, 4 Oct 2017 18:19:33 +0000 (+0300)
Subject: Fixed buffer overread with unix sockets after accept().
X-Git-Tag: release-1.12.2~4
X-Git-Url: http://www.kaiwu.me/postgresql/commit/static/gitweb.js?a=commitdiff_plain;h=cb4dc2720acf49cb8870e5ff4ebd33ad08668e67;p=nginx.git

Fixed buffer overread with unix sockets after accept().

Some OSes (notably macOS, NetBSD, and Solaris) allow unix socket addresses
larger than struct sockaddr_un.  Moreover, some of them (macOS, Solaris)
return socklen of the socket address before it was truncated to fit the
buffer provided.  As such, on these systems socklen must not be used without
additional check that it is within the buffer provided.

Appropriate checks added to ngx_event_accept() (after accept()),
ngx_event_recvmsg() (after recvmsg()), and ngx_set_inherited_sockets()
(after getsockname()).

We also obtain socket addresses via getsockname() in
ngx_connection_local_sockaddr(), but it does not need any checks as
it is only used for INET and INET6 sockets (as there can be no
wildcard unix sockets).
---

diff --git a/src/core/ngx_connection.c b/src/core/ngx_connection.c
index 9b7071d2a..a1baefb9b 100644
--- a/src/core/ngx_connection.c
+++ b/src/core/ngx_connection.c
@@ -165,6 +165,10 @@ ngx_set_inherited_sockets(ngx_cycle_t *cycle)
             continue;
         }
 
+        if (ls[i].socklen > (socklen_t) sizeof(ngx_sockaddr_t)) {
+            ls[i].socklen = sizeof(ngx_sockaddr_t);
+        }
+
         switch (ls[i].sockaddr->sa_family) {
 
 #if (NGX_HAVE_INET6)
diff --git a/src/event/ngx_event_accept.c b/src/event/ngx_event_accept.c
index 87447d089..775637090 100644
--- a/src/event/ngx_event_accept.c
+++ b/src/event/ngx_event_accept.c
@@ -164,6 +164,10 @@ ngx_event_accept(ngx_event_t *ev)
             return;
         }
 
+        if (socklen > (socklen_t) sizeof(ngx_sockaddr_t)) {
+            socklen = sizeof(ngx_sockaddr_t);
+        }
+
         c->sockaddr = ngx_palloc(c->pool, socklen);
         if (c->sockaddr == NULL) {
             ngx_close_accepted_connection(c);
@@ -440,6 +444,10 @@ ngx_event_recvmsg(ngx_event_t *ev)
         c->type = SOCK_DGRAM;
         c->socklen = msg.msg_namelen;
 
+        if (c->socklen > (socklen_t) sizeof(ngx_sockaddr_t)) {
+            c->socklen = sizeof(ngx_sockaddr_t);
+        }
+
 #if (NGX_STAT_STUB)
         (void) ngx_atomic_fetch_add(ngx_stat_active, 1);
 #endif