Re: kern/44594: kernel zlib reports false errors on decompression

[Matthias Drochner <M.Drochner%fz-juelich.de@localhost>]

The following reply was made to PR kern/44594; it has been noted by GNATS.

From: Matthias Drochner <M.Drochner%fz-juelich.de@localhost>
To: <gnats-bugs%NetBSD.org@localhost>
Cc: 
Subject: Re: kern/44594: kernel zlib reports false errors on decompression 
Date: Thu, 17 Feb 2011 19:19:30 +0100

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 Here is the test program.
 
 
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 Content-Type: text/plain; name="compbug.c"; charset="us-ascii"
 Content-Description: compbug.c
 Content-Disposition: attachment; filename="compbug.c"
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <err.h>
 #include "zlib.h"
 
 /* This unpacks into 1508, exactly 52*29. */
 unsigned char text[29] = {
        0xe3,0x60,0xa8,0x9d,0x5e,0xf9,0x9d,0x81,0xc1,0x37,
        0x56,0xc5,0x8f,0x81,0xb7,0x6f,0x07,0xc3,0x28,0x18,
        0x05,0xa3,0x60,0x14,0x8c,0x82,0x61,0x03,0x00
 };
 #define FACTOR 4 /* fails with 1, 2, 4, 13, 26, 52 */
 
 static void *
 myalloc(void *o, unsigned int n, unsigned int s)
 {
 
        return calloc(n, s);
 }
 static void
 myfree(void *o, void *p)
 {
 
        free(p);
 }
 
 int
 main()
 {
        int res, nbuf;
        unsigned char buf1[10000];
        z_stream z;
 
        memset(&z, 0, sizeof(z));
        z.next_in = text;
        z.avail_in = sizeof(text);
        z.zalloc = myalloc;
        z.zfree = myfree;
        z.opaque = 0;
        z.next_out = buf1;
        z.avail_out = FACTOR * sizeof(text);
        res = inflateInit2(&z, -15);
        if (res != Z_OK)
                errx(1, "inflateInit: %d", res);
        nbuf = 1;
        for(;;) {
                res = inflate(&z, Z_SYNC_FLUSH);
                if (res != Z_OK)
                        break;
                if (z.avail_out == 0) {
                        z.next_out = buf1;
                        z.avail_out = FACTOR * sizeof(text);
                        nbuf++;
                }
        }
        if (res != Z_STREAM_END) {
                printf("ai=%d ao=%d bufs=%d out=%ld\n",
                        z.avail_in, z.avail_out, nbuf, z.total_out);
                errx(1, "inflate: %d", res);
        }
        printf("got %ld bytes in %d bufs\n", z.total_out, nbuf);
        return 0;
 }
 
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