On Sun, Jun 24 2018, Denis Fondras <[email protected]> wrote:
> When removing enc(4) interface from rdomain, the kernel panics randomly
> (memcpy() seems to copy outside of the mallocarray() boundaries) with 
> something
> like :
>
> Data modified on freelist: word -35183699295756 of object 0xffff80000059da80 
> size 0x8 previous type free (invalid addr 0x7b44962aa448c22a)
> kernel: protection fault trap, code=0
> Stopped at      malloc+0x4d3:   movq    0x8(%r14),%rbx

[...]

> Here is a fix :
>
> Index: if_enc.c
> ===================================================================
> RCS file: /cvs/src/sys/net/if_enc.c,v
> retrieving revision 1.70
> diff -u -p -r1.70 if_enc.c
> --- if_enc.c  16 Oct 2017 08:22:25 -0000      1.70
> +++ if_enc.c  24 Jun 2018 17:15:32 -0000
> @@ -271,7 +271,7 @@ enc_setif(struct ifnet *ifp, u_int id)
>       if (id > RT_TABLEID_MAX)
>               return (EINVAL);
>  
> -     if (id == 0 || id > enc_max_id) {
> +     if (enc_ifps == NULL || id > enc_max_id) {
>               if ((new = mallocarray(id + 1, sizeof(struct ifnet *),
>                   M_DEVBUF, M_NOWAIT|M_ZERO)) == NULL)
>                       return (ENOBUFS);

This pattern is also used in enc_clone_create(), even if right now we
can't call this function twice for enc0 I think the code should be made
consistent.  ok?


Index: net/if_enc.c
===================================================================
--- net/if_enc.c.orig
+++ net/if_enc.c
@@ -120,7 +120,7 @@ enc_clone_create(struct if_clone *ifc, i
                return (error);
        }
 
-       if (unit == 0 || unit > enc_max_unit) {
+       if (enc_ifps == NULL || unit > enc_max_unit) {
                if ((new = mallocarray(unit + 1, sizeof(struct ifnet *),
                    M_DEVBUF, M_NOWAIT|M_ZERO)) == NULL) {
                        NET_UNLOCK();


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jca | PGP : 0x1524E7EE / 5135 92C1 AD36 5293 2BDF  DDCC 0DFA 74AE 1524 E7EE

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