4.14-stable review patch.  If anyone has any objections, please let me know.


From: Jiri Pirko <j...@mellanox.com>

[ Upstream commit 0f2d2b2736b08dafa3bde31d048750fbc8df3a31 ]

Since mlxsw_sp_fib_create() and mlxsw_sp_mr_table_create()
use ERR_PTR macro to propagate int err through return of a pointer,
the return value is not NULL in case of failure. So if one
of the calls fails, one of vr->fib4, vr->fib6 or vr->mr4_table
is not NULL and mlxsw_sp_vr_is_used wrongly assumes
that vr is in use which leads to crash like following one:

[ 1293.949291] BUG: unable to handle kernel NULL pointer dereference at 
[ 1293.952729] IP: mlxsw_sp_mr_table_flush+0x15/0x70 [mlxsw_spectrum]

Fix this by using local variables to hold the pointers and set vr->*
only in case everything went fine.

Fixes: 76610ebbde18 ("mlxsw: spectrum_router: Refactor virtual router handling")
Fixes: a3d9bc506d64 ("mlxsw: spectrum_router: Extend virtual routers with IPv6 
Fixes: d42b0965b1d4 ("mlxsw: spectrum_router: Add multicast routes notification 
handling functionality")
Signed-off-by: Jiri Pirko <j...@mellanox.com>
Reviewed-by: Ido Schimmel <ido...@mellanox.com>
Signed-off-by: Jiri Pirko <j...@mellanox.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c |   19 ++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -729,26 +729,29 @@ static struct mlxsw_sp_fib *mlxsw_sp_vr_
 static struct mlxsw_sp_vr *mlxsw_sp_vr_create(struct mlxsw_sp *mlxsw_sp,
                                              u32 tb_id)
+       struct mlxsw_sp_fib *fib4;
+       struct mlxsw_sp_fib *fib6;
        struct mlxsw_sp_vr *vr;
        int err;
        vr = mlxsw_sp_vr_find_unused(mlxsw_sp);
        if (!vr)
                return ERR_PTR(-EBUSY);
-       vr->fib4 = mlxsw_sp_fib_create(vr, MLXSW_SP_L3_PROTO_IPV4);
-       if (IS_ERR(vr->fib4))
-               return ERR_CAST(vr->fib4);
-       vr->fib6 = mlxsw_sp_fib_create(vr, MLXSW_SP_L3_PROTO_IPV6);
-       if (IS_ERR(vr->fib6)) {
-               err = PTR_ERR(vr->fib6);
+       fib4 = mlxsw_sp_fib_create(vr, MLXSW_SP_L3_PROTO_IPV4);
+       if (IS_ERR(fib4))
+               return ERR_CAST(fib4);
+       fib6 = mlxsw_sp_fib_create(vr, MLXSW_SP_L3_PROTO_IPV6);
+       if (IS_ERR(fib6)) {
+               err = PTR_ERR(fib6);
                goto err_fib6_create;
+       vr->fib4 = fib4;
+       vr->fib6 = fib6;
        vr->tb_id = tb_id;
        return vr;
-       mlxsw_sp_fib_destroy(vr->fib4);
-       vr->fib4 = NULL;
+       mlxsw_sp_fib_destroy(fib4);
        return ERR_PTR(err);

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