Re: [Xen-devel] [Patch v2 3/4] tools/xenstored: Avoid buffer overflows while setting up sockets

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Ping again?

On 02/12/13 13:18, Andrew Cooper wrote:
> Ping?  This v2 patch appears to have slipped through the cracks from my
> set of Coverity fixes.
>
> ~Andrew
>
> On 25/11/13 14:38, Andrew Cooper wrote:
>> Coverity ID: 1055996 1056002
>>
>> Cache the xs_daemon_socket{,_ro}() strings to save pointlessly
>> re-snprintf()'ing the same path, and add explicit size checks against
>> addr.sun_path before strcpy()'ing into it.
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>> CC: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
>> CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
>> CC: Matthew Daley <mattd@xxxxxxxxxxx>
>>
>> ---
>> Changes in v2:
>>  * Use logic similar to f220279c14
>> ---
>>  tools/xenstore/xenstored_core.c |   27 ++++++++++++++++++---------
>>  1 file changed, 18 insertions(+), 9 deletions(-)
>>
>> diff --git a/tools/xenstore/xenstored_core.c 
>> b/tools/xenstore/xenstored_core.c
>> index ccfdaa3..2324e53 100644
>> --- a/tools/xenstore/xenstored_core.c
>> +++ b/tools/xenstore/xenstored_core.c
>> @@ -1718,6 +1718,9 @@ static void init_sockets(int **psock, int **pro_sock)
>>  {
>>      struct sockaddr_un addr;
>>      int *sock, *ro_sock;
>> +    const char *soc_str = xs_daemon_socket();
>> +    const char *soc_str_ro = xs_daemon_socket_ro();
>> +
>>      /* Create sockets for them to listen to. */
>>      *psock = sock = talloc(talloc_autofree_context(), int);
>>      *sock = socket(PF_UNIX, SOCK_STREAM, 0);
>> @@ -1731,19 +1734,25 @@ static void init_sockets(int **psock, int **pro_sock)
>>      talloc_set_destructor(ro_sock, destroy_fd);
>>  
>>      /* FIXME: Be more sophisticated, don't mug running daemon. */
>> -    unlink(xs_daemon_socket());
>> -    unlink(xs_daemon_socket_ro());
>> +    unlink(soc_str);
>> +    unlink(soc_str_ro);
>>  
>>      addr.sun_family = AF_UNIX;
>> -    strcpy(addr.sun_path, xs_daemon_socket());
>> +
>> +    if(strlen(soc_str) >= sizeof(addr.sun_path))
>> +            barf_perror("socket string '%s' too long", soc_str);
>> +    strcpy(addr.sun_path, soc_str);
>>      if (bind(*sock, (struct sockaddr *)&addr, sizeof(addr)) != 0)
>> -            barf_perror("Could not bind socket to %s", xs_daemon_socket());
>> -    strcpy(addr.sun_path, xs_daemon_socket_ro());
>> +            barf_perror("Could not bind socket to %s", soc_str);
>> +
>> +    if(strlen(soc_str_ro) >= sizeof(addr.sun_path))
>> +            barf_perror("socket string '%s' too long", soc_str_ro);
>> +    strcpy(addr.sun_path, soc_str_ro);
>>      if (bind(*ro_sock, (struct sockaddr *)&addr, sizeof(addr)) != 0)
>> -            barf_perror("Could not bind socket to %s",
>> -                        xs_daemon_socket_ro());
>> -    if (chmod(xs_daemon_socket(), 0600) != 0
>> -        || chmod(xs_daemon_socket_ro(), 0660) != 0)
>> +            barf_perror("Could not bind socket to %s", soc_str_ro);
>> +
>> +    if (chmod(soc_str, 0600) != 0
>> +        || chmod(soc_str_ro, 0660) != 0)
>>              barf_perror("Could not chmod sockets");
>>  
>>      if (listen(*sock, 1) != 0


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