>From 9d370181ec4bc1e252b54dd0e7bb52016f01b238 Mon Sep 17 00:00:00 2001 From: David Henningsson Date: Fri, 16 Oct 2015 22:12:32 +0200 Subject: [PATCH] pstream: Fix use-after-free in srb_callback We need to guard the pstream with an extra ref to ensure it is not destroyed at the time we check whether or not the srbchannel is destroyed. Reported-by: Takashi Iwai BugLink: http://bugzilla.opensuse.org/show_bug.cgi?id=950487 Signed-off-by: David Henningsson --- src/pulsecore/pstream.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/src/pulsecore/pstream.c +++ b/src/pulsecore/pstream.c @@ -216,14 +216,23 @@ fail: } static bool srb_callback(pa_srbchannel *srb, void *userdata) { + bool b; pa_pstream *p = userdata; pa_assert(p); pa_assert(PA_REFCNT_VALUE(p) > 0); pa_assert(p->srb == srb); + pa_pstream_ref(p); + do_pstream_read_write(p); - return p->srb != NULL; + + /* If either pstream or the srb is going away, return false. + We need to check this before p is destroyed. */ + b = (PA_REFCNT_VALUE(p) > 1) && (p->srb == srb); + pa_pstream_unref(p); + + return b; } static void io_callback(pa_iochannel*io, void *userdata) {