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mirror of https://github.com/cwinfo/yggdrasil-go.git synced 2024-11-22 17:40:26 +00:00

fix possible unsafe memory use in Conn.Read

This commit is contained in:
Arceliar 2019-07-17 18:25:38 -05:00
parent 06330f503f
commit 5301207480

View File

@ -125,6 +125,7 @@ func (c *Conn) Read(b []byte) (int, error) {
sinfo := c.session
timer := getDeadlineTimer(&c.readDeadline)
defer util.TimerStop(timer)
var bs []byte
for {
// Wait for some traffic to come through from the session
select {
@ -148,24 +149,18 @@ func (c *Conn) Read(b []byte) (int, error) {
return
}
// Decrypt the packet
bs, isOK := crypto.BoxOpen(&sinfo.sharedSesKey, p.Payload, &p.Nonce)
defer util.PutBytes(bs) // FIXME commenting this out leads to illegal buffer reuse, this implies there's a memory error somewhere and that this is just flooding things out of the finite pool of old slices that get reused
var isOK bool
bs, isOK = crypto.BoxOpen(&sinfo.sharedSesKey, p.Payload, &p.Nonce)
// Check if we were unable to decrypt the packet for some reason and
// return an error if we couldn't
if !isOK {
err = ConnError{errors.New("packet dropped due to decryption failure"), false, true, false, 0}
return
}
// Return the newly decrypted buffer back to the slice we were given
copy(b, bs)
// Trim the slice down to size based on the data we received
if len(bs) < len(b) {
b = b[:len(bs)]
}
// Update the session
sinfo.updateNonce(&p.Nonce)
sinfo.time = time.Now()
sinfo.bytesRecvd += uint64(len(b))
sinfo.bytesRecvd += uint64(len(bs))
}
// Hand over to the session worker
defer func() {
@ -197,9 +192,12 @@ func (c *Conn) Read(b []byte) (int, error) {
}
return 0, err
}
// Copy results to the output slice and clean up
copy(b, bs)
util.PutBytes(bs)
// If we've reached this point then everything went to plan, return the
// number of bytes we populated back into the given slice
return len(b), nil
return len(bs), nil
}
}
}