On Tue, Nov 16, 2021 at 11:50:28AM +0100, Simon Wunderlich wrote: > From: Pavel Skripkin <paskripkin@xxxxxxxxx> > > commit 6f68cd634856f8ca93bafd623ba5357e0f648c68 upstream. > > Syzbot reported ODEBUG warning in batadv_nc_mesh_free(). The problem was > in wrong error handling in batadv_mesh_init(). > > Before this patch batadv_mesh_init() was calling batadv_mesh_free() in case > of any batadv_*_init() calls failure. This approach may work well, when > there is some kind of indicator, which can tell which parts of batadv are > initialized; but there isn't any. > > All written above lead to cleaning up uninitialized fields. Even if we hide > ODEBUG warning by initializing bat_priv->nc.work, syzbot was able to hit > GPF in batadv_nc_purge_paths(), because hash pointer in still NULL. [1] > > To fix these bugs we can unwind batadv_*_init() calls one by one. > It is good approach for 2 reasons: 1) It fixes bugs on error handling > path 2) It improves the performance, since we won't call unneeded > batadv_*_free() functions. > > So, this patch makes all batadv_*_init() clean up all allocated memory > before returning with an error to no call correspoing batadv_*_free() > and open-codes batadv_mesh_free() with proper order to avoid touching > uninitialized fields. > > Link: https://lore.kernel.org/netdev/000000000000c87fbd05cef6bcb0@xxxxxxxxxx/ [1] > Reported-and-tested-by: syzbot+28b0702ada0bf7381f58@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol") > Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx> > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> > [ bp: 4.4 backport: Drop batadv_v_mesh_{init,free} which are not there yet. ] > Signed-off-by: Sven Eckelmann <sven@xxxxxxxxxxxxx> > --- > Submission according to the request in > https://lore.kernel.org/all/163559888490194@xxxxxxxxx/ Now queued up, thanks. greg k-h
