Date: Wed, 20 Mar 2002 16:13:11 +0000 From: Ian Dowse <iedowse@maths.tcd.ie> To: Eugene Grosbein <eugen@grosbein.pp.ru> Cc: Matthew Dillon <dillon@apollo.backplane.com>, FreeBSD-gnats-submit@FreeBSD.ORG, freebsd-bugs@FreeBSD.ORG, Kirk McKusick <mckusick@mckusick.com> Subject: Re: kern/35969: kernel option PPP_DEFLATE often procudes kernel panics; PPP_BSDCOMP sometimes procudes stalled connections Message-ID: <200203201613.aa16423@salmon.maths.tcd.ie> In-Reply-To: Your message of "Wed, 20 Mar 2002 21:35:03 %2B0700." <20020320213503.A344@grosbein.pp.ru>
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In message <20020320213503.A344@grosbein.pp.ru>, Eugene Grosbein writes:
>It seems, that commit affected src/lib/libz/infblock.c
>and it's possible it still contatins the bug that is fixed now in the kernel.
Yes, I had seen the libc/libz code too. At first glance it appears
to have a similar problem:
>@@ -329,6 +334,7 @@
> }
> s->sub.decode.codes = c;
> }
>+ ZFREE(z, s->sub.trees.blens);
> s->mode = CODES;
> case CODES:
> UPDATE
However the structure of struct inflate_blocks_state is different
in libz, so it is mostly safe because decode.codes and trees.blens
are unlikely to overlap on most platforms:
union {
uInt left; /* if STORED, bytes left to copy */
struct {
uInt table; /* table lengths (14 bits) */
uInt index; /* index into blens (or border) */
uIntf *blens; /* bit lengths of codes */
uInt bb; /* bit length tree depth */
inflate_huft *tb; /* bit length decoding tree */
} trees; /* if DTREE, decoding info for trees */
struct {
inflate_codes_statef
*codes;
} decode; /* if CODES, current state */
} sub; /* submode */
The patch applied to libc/libz seems to match exactly what appeared
in the official zlib 1.1.4 release, but it is still very dodgy
programming by the zlib people...
Ian
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