sssd/0037-Prevent-use-after-free-in-fd_input_available.patch
Lukas Slebodnik eb6c560542 Resolves: rhbz#1369130 - nss_sss should not link against libpthread
Resolves: rhbz#1392916 - sssd failes to start after update
Resolves: rhbz#1398789 - SELinux is preventing sssd from 'write' accesses
                           on the directory /etc/sssd
2016-12-13 20:10:27 +01:00

73 lines
2.6 KiB
Diff

From d2f8e3876810cf99228827432ea4f4a59877448d Mon Sep 17 00:00:00 2001
From: Carl Henrik Lunde <chlunde@ifi.uio.no>
Date: Thu, 1 Dec 2016 00:09:00 +0100
Subject: [PATCH 37/39] Prevent use after free in fd_input_available
When both TEVENT_FD_WRITE and TEVENT_FD_READ are set, and an error/EOF
occurs when reading from the socket, we will get a use after free
in the second call ares_process_fd. The first call will free the watch
structure via a callback.
Prevent this by calling ares_process_fd only once.
Invalid read of size 4
at fd_input_available (async_resolv.c:147)
by epoll_event_loop (tevent_epoll.c:728)
by epoll_event_loop_once (tevent_epoll.c:926)
by std_event_loop_once (tevent_standard.c:114)
by _tevent_loop_once (tevent.c:533)
by tevent_common_loop_wait (tevent.c:637)
by std_event_loop_wait (tevent_standard.c:140)
by server_loop (server.c:702)
by main (data_provider_be.c:587)
Address ... is 112 bytes inside a block of size 136 free'd
at free (vg_replace_malloc.c:530)
by _talloc_free_internal (talloc.c:1116)
by _talloc_free (talloc.c:1647)
by ares__close_sockets (ares__close_sockets.c:50)
by handle_error (ares_process.c:679)
by read_tcp_data (ares_process.c:391)
by processfds (ares_process.c:138)
by fd_input_available (async_resolv.c:144)
by epoll_event_loop (tevent_epoll.c:728)
by epoll_event_loop_once (tevent_epoll.c:926)
by std_event_loop_once (tevent_standard.c:114)
by _tevent_loop_once (tevent.c:533)
by tevent_common_loop_wait (tevent.c:637)
by std_event_loop_wait (tevent_standard.c:140)
by server_loop (server.c:702)
Resolves:
https://fedorahosted.org/sssd/ticket/3250
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
(cherry picked from commit 9676b464dd428557ff5a648e1351a3972440396f)
(cherry picked from commit fefdd70237cbe82af7d8845131e45401e73b3b07)
---
src/resolv/async_resolv.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/src/resolv/async_resolv.c b/src/resolv/async_resolv.c
index e85955677..47b4db7ec 100644
--- a/src/resolv/async_resolv.c
+++ b/src/resolv/async_resolv.c
@@ -140,12 +140,9 @@ fd_input_available(struct tevent_context *ev, struct tevent_fd *fde,
return;
}
- if (flags & TEVENT_FD_READ) {
- ares_process_fd(watch->ctx->channel, watch->fd, ARES_SOCKET_BAD);
- }
- if (flags & TEVENT_FD_WRITE) {
- ares_process_fd(watch->ctx->channel, ARES_SOCKET_BAD, watch->fd);
- }
+ ares_process_fd(watch->ctx->channel,
+ flags & TEVENT_FD_READ ? watch->fd : ARES_SOCKET_BAD,
+ flags & TEVENT_FD_WRITE ? watch->fd : ARES_SOCKET_BAD);
}
static void
--
2.11.0