Hi Qian,
 The code that you mention still exists in the trunk and does not check for
the len before calling memcpy. Please open a jira on this.

The interesting thing though is that the len is -1. Do you have any test
case or  a test scenario where it can be reproduced. It would be interesting
to see why this is happening. We should not be getting a -1 len value from
the server. 


Thanks
mahadev


On 12/14/09 6:19 AM, "Qian Ye" <yeqian....@gmail.com> wrote:

> Hi guys:
> 
> I encountered a problem today that the Zookeeper C Client (version 3.2.0)
> core dump when reconnected and did some operations on the zookeeper server
> which just restarted. The gdb infomation is like:
> 
> (gdb) bt
> #0  0x000000302af71900 in memcpy () from /lib64/tls/libc.so.6
> #1  0x000000000047bfe4 in ia_deserialize_string (ia=Variable "ia" is not
> available.) at src/recordio.c:270
> #2  0x000000000047ed20 in deserialize_CreateResponse (in=0x9cd870,
> tag=0x50a74e "reply", v=0x409ffe70) at generated/zookeeper.jute.c:679
> #3  0x000000000047a1d0 in zookeeper_process (zh=0x9c8c70, events=Variable
> "events" is not available.) at src/zookeeper.c:1895
> #4  0x00000000004815e6 in do_io (v=Variable "v" is not available.) at
> src/mt_adaptor.c:310
> #5  0x000000302b80610a in start_thread () from /lib64/tls/libpthread.so.0
> #6  0x000000302afc6003 in clone () from /lib64/tls/libc.so.6
> #7  0x0000000000000000 in ?? ()
> (gdb) f 1
> #1  0x000000000047bfe4 in ia_deserialize_string (ia=Variable "ia" is not
> available.) at src/recordio.c:270
> 270     in src/recordio.c
> (gdb) info locals
> priv = (struct buff_struct *) 0x9cd8d0
> *len = -1*
> rc = Variable "rc" is not available.
> 
> According to the source code,
> int ia_deserialize_string(struct iarchive *ia, const char *name, char **s)
> {
>     struct buff_struct *priv = ia->priv;
>     int32_t len;
>     *int rc = ia_deserialize_int(ia, "len", &len);*
>     if (rc < 0)
>         return rc;
>     if ((priv->len - priv->off) < len) {
>         return -E2BIG;
>     }
>     *s = malloc(len+1);
>     if (!*s) {
>         return -ENOMEM;
>     }
>     memcpy(*s, priv->buffer+priv->off, len);
>     (*s)[len] = '\0';
>     priv->off += len;
>     return 0;
> }
> 
> the variable len is set by ia_deserialize_int, and the returned len doesn't
> been checked, so the client segment fault when trying to memcpy -1 byte
> data.
> I'm not sure why the client got the len variable -1 when deserialize the
> response from the server, I'm also not sure whether it is an known issue.
> Could any
> one give me some information about this problem?

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