Sorry for being that late in the game, but I think the patch should be
reverted:
Am Freitag, den 03.04.2009, 00:45 +0100 schrieb Chris Webb:
> I have an amd64 host exporting around 70 iscsi targets (each with one LUN)
> using tgtd. Exporting the targets works fine, but when I run a 'sendtargets'
> discovery against the host, tgtd segfaults in conn_exit() because of heap
> corruption when it tries to free conn->rsp_buffer.
>
> (gdb) print conn->rsp.datasize
> $12 = 13104
>
> It turns out conn->rsp_buffer is being filled beyond INCOMING_BUFSIZE (8192)
> by text_key_add() because it checks for overflow of conn->tx_size instead of
> conn->rsp.datasize. The faulty test is fixed by:
>
> Signed-off-by: Chris Webb <chris@xxxxxxxxxxxx>
>
> diff -uNrp a/usr/iscsi/iscsid.c b/usr/iscsi/iscsid.c
> --- a/usr/iscsi/iscsid.c 2009-03-28 22:54:21.000000000 +0000
> +++ b/usr/iscsi/iscsid.c 2009-03-28 23:09:06.000000000 +0000
> @@ -160,7 +160,7 @@ void text_key_add(struct iscsi_connectio
> if (!conn->rsp.datasize)
> conn->rsp.data = conn->rsp_buffer;
>
> - if (conn->tx_size + len > INCOMING_BUFSIZE) {
> + if (conn->rsp.datasize + len > INCOMING_BUFSIZE) {
> log_warning("Dropping key (%s=%s)", key, value);
> return;
> }
>
>
> However, I don't think this is the right fix,
No, it actually is.
> because sendtargets would
> remain broken as soon as the size of the target list exceeed
> INCOMING_BUFSIZE. The following patch instead realloc()s the response buffer
> if it needs to grow to accommodate the target list:
The buffer cannot be arbitrarily reallocated. Ultimately this will lead
to a violation of the MaxRecvDSL the initiator (implicitly) declared. To
get this right the target list will have to be split into multiple PDUs,
which is AFAIK not supported.
Arne
> Signed-off-by: Chris Webb <chris@xxxxxxxxxxxx>
>
> diff -uNrp a/usr/iscsi/iscsid.c b/usr/iscsi/iscsid.c
> --- a/usr/iscsi/iscsid.c 2009-03-28 22:54:21.000000000 +0000
> +++ b/usr/iscsi/iscsid.c 2009-03-28 23:26:48.000000000 +0000
> @@ -160,12 +160,18 @@ void text_key_add(struct iscsi_connectio
> if (!conn->rsp.datasize)
> conn->rsp.data = conn->rsp_buffer;
>
> - if (conn->tx_size + len > INCOMING_BUFSIZE) {
> - log_warning("Dropping key (%s=%s)", key, value);
> - return;
> + buffer = conn->rsp_buffer;
> +
> + if (conn->rsp.datasize + len > INCOMING_BUFSIZE) {
> + buffer = realloc(buffer, conn->rsp.datasize + len);
> + if (buffer)
> + conn->rsp_buffer = buffer;
> + else {
> + log_warning("Dropping key (%s=%s)", key, value);
> + return;
> + }
> }
>
> - buffer = conn->rsp_buffer;
> buffer += conn->rsp.datasize;
> conn->rsp.datasize += len;
>
>
> Best wishes,
>
> Chris.
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