From b1e4836bcfbfdec0504219ed490c5f53860d8106 Mon Sep 17 00:00:00 2001 From: Ingela Anderton Andin Date: Tue, 1 Mar 2016 15:19:36 +0100 Subject: Skips any sockets with unsupported protocols. Patch from end of PR 864 Fixes problem reported in the PR by jeckersb In this error case, a negative file descriptor is now saved at listensock[i], which leads to a buffer overflow later on at https://github.com/msantos/otp/blob/epmd-IPv6-node-reg2/erts/epmd/src/epmd_srv.c#L498 when calling FD_ISSET(listensock[i],&read_mask). To reproduce this: Completely disable IPv6 with ipv6.disable=1 on the kernel command line Build with fortified code (RHEL/CentOS default): CFLAGS='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -fno-strict-aliasing' --- erts/epmd/src/epmd_srv.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/erts/epmd/src/epmd_srv.c b/erts/epmd/src/epmd_srv.c index 55ec0f7b6c..e1bac99ef9 100644 --- a/erts/epmd/src/epmd_srv.c +++ b/erts/epmd/src/epmd_srv.c @@ -380,7 +380,7 @@ void run(EpmdVars *g) epmd_cleanup_exit(g,1); } } - g->listenfd[i] = listensock[i]; + g->listenfd[bound++] = listensock[i]; #if HAVE_DECL_IPV6_V6ONLY opt = 1; @@ -439,8 +439,6 @@ void run(EpmdVars *g) } } - bound++; - if(listen(listensock[i], SOMAXCONN) < 0) { dbg_perror(g,"failed to listen on socket"); epmd_cleanup_exit(g,1); @@ -451,6 +449,7 @@ void run(EpmdVars *g) dbg_perror(g,"unable to bind any address"); epmd_cleanup_exit(g,1); } + num_sockets = bound; #ifdef HAVE_SYSTEMD_DAEMON } sd_notifyf(0, "READY=1\n" @@ -495,8 +494,8 @@ void run(EpmdVars *g) } for (i = 0; i < num_sockets; i++) - if (FD_ISSET(listensock[i],&read_mask)) { - if (do_accept(g, listensock[i]) && g->active_conn < g->max_conn) { + if (FD_ISSET(g->listenfd[i],&read_mask)) { + if (do_accept(g, g->listenfd[i]) && g->active_conn < g->max_conn) { /* * The accept() succeeded, and we have at least one file * descriptor still free, which means that another accept() -- cgit v1.2.3