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
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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);