Subject: webalizer: various buffer overflows
Package: webalizer
Version: 2.01.10-27
Severity: important
Tags: patch
Hello,
I have found some more buffer overflows in webalizer. People from Debian seem to
have worked on this earlier on, and here are some more bugs to fix. None of them
seem to have any security impact.
The first overflow occurs when parsing FTP xfer log files, specifically the
IDENT
part which can write far beyond its limits. During my testing, I was unable to
make this bug crash the program because of the way things are laid out in
memory,
but I still think it is worth fixing, as writing outside of char buffers in C is
a serious matter. You can test it with the attached ftplog.txt file (but you
have
to add a printf() statement to verify that the overflow occurs).
The second overflow occurs when parsing webalizer.conf, where bad config files
cause
Segmentation faults. I have attached a webalizer.conf file that causes this
problem
in two different ways.
The third overflow is an off-by-one bug in the DNS handling.
I have attached a patch that corrects all three issues.
// Ulf Härnhammar, Debian Security Audit Project
-- System Information:
Debian Release: testing/unstable
APT prefers testing
APT policy: (500, 'testing')
Architecture: i386 (i686)
Shell: /bin/sh linked to /bin/bash
Kernel: Linux 2.6.12-1-686
Locale: LANG=en_US, LC_CTYPE=en_US (charmap=ISO-8859-1)
Versions of packages webalizer depends on:
ii debconf [debconf-2.0] 1.4.62 Debian configuration management sy
ii libc6 2.3.5-8 GNU C Library: Shared libraries an
ii libdb4.2 4.2.52-18 Berkeley v4.2 Database Libraries [
ii libgd2-xpm 2.0.33-2 GD Graphics Library version 2
ii libpng12-0 1.2.8rel-5 PNG library - runtime
ii zlib1g 1:1.2.3-8 compression library - runtime
webalizer recommends no packages.
-- debconf information excluded
x Dec 18 13:18:15 2005 5 5 xy 5 xy xy xy
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UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU a
a
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--- parser.c.old 2005-12-18 13:34:00.000000000 +0100
+++ parser.c 2005-12-18 13:38:11.000000000 +0100
@@ -134,7 +134,7 @@ int parse_record(char *buffer)
int parse_record_ftp(char *buffer)
{
int size;
- int i,j;
+ int i,j,count;
char *cp1, *cp2, *cpx, *cpy, *eob;
size = strlen(buffer); /* get length of buffer */
@@ -206,8 +206,8 @@ int parse_record_ftp(char *buffer)
if (cp1<eob) cp1++;
while (*cp1!=0 && cp1<eob) cp1++;
if (cp1<eob) cp1++;
- cp2=log_rec.ident;
- while (*cp1!=0 && cp1<eob) *cp2++ = *cp1++;
+ cp2=log_rec.ident;count=MAXIDENT-1;
+ while (*cp1!=0 && cp1<eob && count) { *cp2++ = *cp1++; count--; }
*cp2='\0';
/* return appropriate response code */
--- webalizer.c.old 2005-12-18 12:42:55.000000000 +0100
+++ webalizer.c 2005-12-18 12:49:58.000000000 +0100
@@ -1498,7 +1498,7 @@ void get_config(char *fname)
char keyword[32];
char value[132];
char *cp1, *cp2;
- int i,key;
+ int i,key,count;
int num_kwords=sizeof(kwords)/sizeof(char *);
if ( (fp=fopen(fname,"r")) == NULL)
@@ -1514,14 +1514,14 @@ void get_config(char *fname)
if ( (buffer[0]=='#') || isspace((int)buffer[0]) ) continue;
/* Get keyword */
- cp1=buffer;cp2=keyword;
- while ( isalnum((int)*cp1) ) *cp2++ = *cp1++;
+ cp1=buffer;cp2=keyword;count=31;
+ while ( (isalnum((int)*cp1)) && count ) { *cp2++ = *cp1++; count--; }
*cp2='\0';
/* Get value */
- cp2=value;
+ cp2=value;count=131;
while ( (*cp1!='\n')&&(*cp1!='\0')&&(isspace((int)*cp1)) ) cp1++;
- while ( (*cp1!='\n')&&(*cp1!='\0') ) *cp2++ = *cp1++;
+ while ( (*cp1!='\n')&&(*cp1!='\0')&&count ) { *cp2++ = *cp1++; count--; }
*cp2--='\0';
while ( (isspace((int)*cp2)) && (cp2 != value) ) *cp2--='\0';
--- dns_resolv.c.old 2005-12-18 12:21:48.000000000 +0100
+++ dns_resolv.c 2005-12-18 12:23:04.000000000 +0100
@@ -159,7 +159,7 @@ void resolve_dns(struct log_struct *log_
strncpy (log_rec->hostname,
((struct dnsRecord *)response.data)->hostName,
MAXHOST);
- log_rec->hostname[MAXHOST]=0;
+ log_rec->hostname[MAXHOST-1]=0;
if (debug_mode)
fprintf(stderr," found: %s (%ld)\n",
log_rec->hostname, alignedRecord.timeStamp);
