[Xorp-cvs] XORP cvs commit: xorp/libxorp

[Atanu Ghosh]

Hi,

It looks like the problem only occurs on xorp13 the AMD64 machine.

   Atanu.

>>>>> "Atanu" == Atanu Ghosh <atanu@ICSI.Berkeley.EDU> writes:

    Atanu> The function x_vasprintf takes printf style arguments
    Atanu> (varargs) and returns a malloc'd buffer with all the
    Atanu> output. Internally this function starts with a buffer of size
    Atanu> 1025, it then calls vsnprintf with the buffer. If the buffer
    Atanu> is not large enough a new buffer is allocated and a second
    Atanu> try is made to format the arguments. The problem is that in
    Atanu> the second and subsequent calls to vnsprintf the varargs
    Atanu> pointer is in the wrong place. I therefore used va_copy to
    Atanu> pass the same varargs pointer to vsnprintf every time.

    Atanu> I saw the problem when tracing BGP an update message packed
    Atanu> with NLRIs required a buffer of 21060 bytes. The vsnprintf
    Atanu> routine ends up accessing parts of that stack that it
    Atanu> shouldn't.

    Atanu> I should have guessed that va_copy was new. I'll fix the
    Atanu> problem in x_asprintf.

    Atanu>       Atanu.

>>>>> "Pavlin" == Pavlin Radoslavov <pavlin@icir.org> writes:

    >>> CVSROOT: /usr/local/www/data/cvs Module name: xorp Changes by:
    >>> atanu@xorpc.icir.org 2005-12-21 01:24:47 UTC
    >>> 
    >>> XORP CVS repository
    >>> 
    >>> 
    >>> Modified files: libxorp xlog.c
    >>> 
    >>> Log message: Take a copy of the variable arguments so they can
    >>> be used multiple times.

    Pavlin> Introducing va_copy() breaks the compilation on FreeBSD-4.10
    Pavlin> with the default compiler (gcc-2.95.4):

    Pavlin> xlog.c: In function `x_vasprintf': xlog.c:1162: warning:
    Pavlin> implicit declaration of function `va_copy' gmake[3]: ***
    Pavlin> [xlog.lo] Error 1

    Pavlin> Can you give an example where the original implementation
    Pavlin> fails.

    Pavlin> Pavlin

    >>> Also fix a possible double free issue which could never happen.
    >>> 
    >>> Revision Changes Path 1.13 +5 -2; commitid: af7343a8aede7ea6;
    >>> xorp/libxorp/xlog.c
    >>> _______________________________________________ Xorp-cvs mailing
    >>> list Xorp-cvs@icir.org
    >>> http://mailman.ICSI.Berkeley.EDU/mailman/listinfo/xorp-cvs

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