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[Bug libc/4940] New: Sprintf injecting extra data


With the following code, span is set to 1 and tape is set to 0.

uint32_t put_fileinfo (MYSQL mysql, _filedata *fd, uint32_t span, uint32_t tape)
{
char sql[4096];
int x;

printf ("span = %d, tape = %d\n",span,tape);

memset (sql,0,4096);
sprintf (sql, "INSERT INTO files VALUES
(\"%s\",\"%s\",\"%d\",\"%ld\",\"%ld\",\"%ld\",\"%lld\",\"%ld\",\"%ld\",\"%ld\",\"%d\",\"%d\",\"%d\",\"%ld\",\"%ld\",now(),\"%ld\")",
        fd->path, fd->name, fd->mode, fd->uid, fd->gid, fd->type, fd->size,
fd->dev, fd->rdev, fd->atime, fd->mtime, fd->ctime, fd->begin, fd->end, span, tape);
printf ("span = %d, tape = %d\n",span,tape);

x = do_sql(mysql, sql,1);
return (x);
}

Using the above code, three extra parameters are injected into the "sql" string
after the fd->rdev parameter.  Here is example contents of SQL using the above code:
INSERT INTO files VALUES
("./src/.svn/text-base","tapeerase.svn-base","420","0","0","32768","46","769","0","0","0","1187550529","1157119100","1170011684","0",now(),"296")

Again, the values of span and tape are 1 and 0 respectively, checked before and
after the execution of the sprintf statement.

If I add "%ld %ld %ld" to the end of the format string, the correct data is
output in these last 3 positions (and gcc complains about the imbalance between
the format and the parameters).

glibc 2.3.5 as distributed with Slackware 10.2, gcc 3.4.6, AMD X2 4600 running
in 32 bit mode.

-- 
           Summary: Sprintf injecting extra data
           Product: glibc
           Version: 2.3.5
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper at redhat dot com
        ReportedBy: ron at rongage dot org
                CC: glibc-bugs at sources dot redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=4940

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