From fcb25077852446a0a1ee16c24501ee2190c14f5f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 21 Sep 2023 08:46:26 +0000 Subject: [PATCH 1/2] net: fix possible store tearing in neigh_periodic_work() stable inclusion from stable-v5.10.198 commit 2ea52a2fb8e87067e26bbab4efb8872639240eb0 category: bugfix issue: #I98WSG CVE: CVE-2023-52522 Signed-off-by: wanxiaoqing --------------------------------------- [ Upstream commit 25563b581ba3a1f263a00e8c9a97f5e7363be6fd ] While looking at a related syzbot report involving neigh_periodic_work(), I found that I forgot to add an annotation when deleting an RCU protected item from a list. Readers use rcu_deference(*np), we need to use either rcu_assign_pointer() or WRITE_ONCE() on writer side to prevent store tearing. I use rcu_assign_pointer() to have lockdep support, this was the choice made in neigh_flush_dev(). Fixes: 767e97e1e0db ("neigh: RCU conversion of struct neighbour") Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Reviewed-by: Simon Horman Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: wanxiaoqing --- net/core/neighbour.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/core/neighbour.c b/net/core/neighbour.c index d08874499f2b..6553425be38a 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -935,7 +935,9 @@ static void neigh_periodic_work(struct work_struct *work) (state == NUD_FAILED || !time_in_range_open(jiffies, n->used, n->used + NEIGH_VAR(n->parms, GC_STALETIME)))) { - *np = n->next; + rcu_assign_pointer(*np, + rcu_dereference_protected(n->next, + lockdep_is_held(&tbl->lock))); neigh_mark_dead(n); write_unlock(&n->lock); neigh_cleanup_and_release(n); -- Gitee From 224f82b7a6033d1aa6bc34a2cfd2373c47b4dd80 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Mon, 11 Dec 2023 10:16:24 +0200 Subject: [PATCH 2/2] drm: Don't unref the same fb many times by mistake due to deadlock handling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit stable inclusion from stable-v5.10.210 commit f55261469be87c55df13db76dc945f6bcd825105 category: bugfix issue: #I99TT1 CVE: CVE-2023-52486 Signed-off-by: wanxiaoqing --------------------------------------- commit cb4daf271302d71a6b9a7c01bd0b6d76febd8f0c upstream. If we get a deadlock after the fb lookup in drm_mode_page_flip_ioctl() we proceed to unref the fb and then retry the whole thing from the top. But we forget to reset the fb pointer back to NULL, and so if we then get another error during the retry, before the fb lookup, we proceed the unref the same fb again without having gotten another reference. The end result is that the fb will (eventually) end up being freed while it's still in use. Reset fb to NULL once we've unreffed it to avoid doing it again until we've done another fb lookup. This turned out to be pretty easy to hit on a DG2 when doing async flips (and CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y). The first symptom I saw that drm_closefb() simply got stuck in a busy loop while walking the framebuffer list. Fortunately I was able to convince it to oops instead, and from there it was easier to track down the culprit. Cc: stable@vger.kernel.org Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20231211081625.25704-1-ville.syrjala@linux.intel.com Acked-by: Javier Martinez Canillas Signed-off-by: Greg Kroah-Hartman Signed-off-by: wanxiaoqing --- drivers/gpu/drm/drm_plane.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c index 24f643982903..79249568bdec 100644 --- a/drivers/gpu/drm/drm_plane.c +++ b/drivers/gpu/drm/drm_plane.c @@ -1213,6 +1213,7 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev, out: if (fb) drm_framebuffer_put(fb); + fb = NULL; if (plane->old_fb) drm_framebuffer_put(plane->old_fb); plane->old_fb = NULL; -- Gitee