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Merge pull request #462 from Arceliar/fixes

fix possible unsafe memory use in Conn.Read
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Arceliar 2019-07-17 18:33:35 -05:00 committed by GitHub
commit c36da7b814
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@ -125,6 +125,7 @@ func (c *Conn) Read(b []byte) (int, error) {
sinfo := c.session sinfo := c.session
timer := getDeadlineTimer(&c.readDeadline) timer := getDeadlineTimer(&c.readDeadline)
defer util.TimerStop(timer) defer util.TimerStop(timer)
var bs []byte
for { for {
// Wait for some traffic to come through from the session // Wait for some traffic to come through from the session
select { select {
@ -148,24 +149,18 @@ func (c *Conn) Read(b []byte) (int, error) {
return return
} }
// Decrypt the packet // Decrypt the packet
bs, isOK := crypto.BoxOpen(&sinfo.sharedSesKey, p.Payload, &p.Nonce) var isOK bool
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 bs, isOK = crypto.BoxOpen(&sinfo.sharedSesKey, p.Payload, &p.Nonce)
// Check if we were unable to decrypt the packet for some reason and // Check if we were unable to decrypt the packet for some reason and
// return an error if we couldn't // return an error if we couldn't
if !isOK { if !isOK {
err = ConnError{errors.New("packet dropped due to decryption failure"), false, true, false, 0} err = ConnError{errors.New("packet dropped due to decryption failure"), false, true, false, 0}
return 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 // Update the session
sinfo.updateNonce(&p.Nonce) sinfo.updateNonce(&p.Nonce)
sinfo.time = time.Now() sinfo.time = time.Now()
sinfo.bytesRecvd += uint64(len(b)) sinfo.bytesRecvd += uint64(len(bs))
} }
// Hand over to the session worker // Hand over to the session worker
defer func() { defer func() {
@ -197,9 +192,12 @@ func (c *Conn) Read(b []byte) (int, error) {
} }
return 0, err 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 // If we've reached this point then everything went to plan, return the
// number of bytes we populated back into the given slice // number of bytes we populated back into the given slice
return len(b), nil return len(bs), nil
} }
} }
} }