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devip: verify ifcid on routehint check, check Route.ref for free'd routes 

v4lookup() and v6lookup() do not acquire the routelock, so it is
possible to hit routes that are on the freelist. to detect these,
we set ref to 0 and check for this case, avoiding overriding the ifc.

re-evaluate routes when the ifcid on the route hint doesnt match.
front
cinap_lenrek 2018-04-22 18:42:22 +02:00
parent 638b4a1ec1
commit 575398eb9b
1 changed files with 27 additions and 9 deletions
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36
sys/src/9/ip/iproute.c
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@ -22,6 +22,7 @@ freeroute(Route *r)
{ {
Route **l; Route **l;
r->ref = 0;
r->left = nil; r->left = nil;
r->right = nil; r->right = nil;
if(r->type & Rv4) if(r->type & Rv4)
@ -541,8 +542,13 @@ v4lookup(Fs *f, uchar *a, uchar *s, Routehint *rh)
Route *p, *q; Route *p, *q;
Ipifc *ifc; Ipifc *ifc;
if(rh != nil && rh->r != nil && rh->r->ifc != nil && rh->rgen == v4routegeneration) if(rh != nil
return rh->r; && rh->rgen == v4routegeneration
&& (q = rh->r) != nil
&& (ifc = q->ifc) != nil
&& q->ifcid == ifc->ifcid
&& q->ref > 0)
return q;
la = nhgetl(a); la = nhgetl(a);
ls = nhgetl(s); ls = nhgetl(s);
@ -570,7 +576,10 @@ v4lookup(Fs *f, uchar *a, uchar *s, Routehint *rh)
p = p->mid; p = p->mid;
} }
if(q != nil && (q->ifc == nil || q->ifcid != q->ifc->ifcid)){ if(q == nil || q->ref == 0)
return nil;
if(q->ifc == nil || q->ifcid != q->ifc->ifcid){
if(q->type & Rifc) { if(q->type & Rifc) {
hnputl(gate+IPv4off, q->v4.address); hnputl(gate+IPv4off, q->v4.address);
memmove(gate, v4prefix, IPv4off); memmove(gate, v4prefix, IPv4off);
@ -602,13 +611,19 @@ v6lookup(Fs *f, uchar *a, uchar *s, Routehint *rh)
Ipifc *ifc; Ipifc *ifc;
int h; int h;
if(isv4(a) && isv4(s)) if(isv4(s)){
return v4lookup(f, a+IPv4off, s+IPv4off, rh); if(isv4(a))
if(isv4(s)) return v4lookup(f, a+IPv4off, s+IPv4off, rh);
return nil; return nil;
}
if(rh != nil && rh->r != nil && rh->r->ifc != nil && rh->rgen == v6routegeneration) if(rh != nil
return rh->r; && rh->rgen == v6routegeneration
&& (q = rh->r) != nil
&& (ifc = q->ifc) != nil
&& q->ifcid == ifc->ifcid
&& q->ref > 0)
return q;
for(h = 0; h < IPllen; h++){ for(h = 0; h < IPllen; h++){
la[h] = nhgetl(a+4*h); la[h] = nhgetl(a+4*h);
@ -668,7 +683,10 @@ v6lookup(Fs *f, uchar *a, uchar *s, Routehint *rh)
next: ; next: ;
} }
if(q != nil && (q->ifc == nil || q->ifcid != q->ifc->ifcid)){ if(q == nil || q->ref == 0)
return nil;
if(q->ifc == nil || q->ifcid != q->ifc->ifcid){
if(q->type & Rifc) { if(q->type & Rifc) {
for(h = 0; h < IPllen; h++) for(h = 0; h < IPllen; h++)
hnputl(gate+4*h, q->v6.address[h]); hnputl(gate+4*h, q->v6.address[h]);