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ip/tinc: handle single byte noop and end-of-option-list tcp options in clampmss()

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This commit is contained in:
cinap_lenrek 2017-12-17 20:20:17 +01:00
parent 15ff38e818
commit 0affe02b61
1 changed files with 12 additions and 1 deletions
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13
sys/src/cmd/ip/tinc.c
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@ -970,9 +970,20 @@ clampmss(Host *d, uchar *p, int n, int o)
return; return;
if((e = p+(p[12]>>4)*4) > p+n) if((e = p+(p[12]>>4)*4) > p+n)
return; return;
for(h = p+TcpHdr; h+4 <= e && h[1] > 0; h += h[1]) for(h = p+TcpHdr; h < e;){
switch(h[0]){
case 0:
return;
case 1:
h++;
continue;
}
if(h[1] < 2 || h[1] > e - h)
return;
if(h[0] == 2 && h[1] == 4) if(h[0] == 2 && h[1] == 4)
goto Found; goto Found;
h += h[1];
}
return; return;
Found: Found:
oldmss = h[2]<<8 | h[3]; oldmss = h[2]<<8 | h[3];