0001337: busybox's awk crashes when 'printf' handles '*' qualifier

(0002343)
vda
05-07-07 14:51

Actually, GNU awk won't be happy either:

# /usr/bin/awk 'END{ printf "%*s\n", tttt }' < /dev/null; echo $?
awk: fatal: not enough arguments to satisfy format string
        `%*s
'
          ^ ran out for this one

# /usr/bin/awk --version
GNU Awk 3.1.5
Copyright (C) 1989, 1991-2005 Free Software Foundation.

What do you prefer, nice(r) error msg instead of SEGV?

For the record, SEGV happens here:
last sprintf gets format "%*s" but only one argument "" intead of (int,char*) pair it expects.

static char *awk_printf(node *n)
{
        char *b = NULL;
        char *fmt, *s, *f;
        const char *s1;
        int i, j, incr, bsize;
        char c, c1;
        var *v, *arg;

        v = nvalloc(1);
        fmt = f = xstrdup(getvar_s(evaluate(nextarg(&n), v)));

        i = 0;
        while (*f) {
                s = f;
                while (*f && (*f != '%' || *(++f) == '%'))
                        f++;
                while (*f && !isalpha(*f))
                        f++;

                incr = (f - s) + MAXVARFMT;
                qrealloc(&b, incr + i, &bsize);
                c = *f;
                if (c != '\0') f++;
                c1 = *f;
                *f = '\0';
                arg = evaluate(nextarg(&n), v);

                j = i;
                if (c == 'c' || !c) {
                        i += sprintf(b+i, s, is_numeric(arg) ?
                                        (char)getvar_i(arg) : *getvar_s(arg));

                } else if (c == 's') {
                        s1 = getvar_s(arg);
                        qrealloc(&b, incr+i+strlen(s1), &bsize);
// b='' i=0, bsize=443 242 s='%*s' s1=''
                        i += sprintf(b+i, s, s1);

(0002346)
ykaliuta
05-08-07 09:08

Ok :)

$ gawk 'END{printf "%0*d%*s\n", a, b, c, "aa"}' < /dev/null
0aa
$ busybox awk 'END{printf "%0*d%*s\n", a, b, c, "aa"}' < /dev/null
Segmentation fault

In any case, I think that yes, the main problem is SIGSEGV.

(0002351)
vda
05-09-07 14:58

Minimally fixed in rev 18596 (will error out instead of SEGVing). Thanks.

Issue History
Date Modified	Username	Field	Change
05-07-07 07:22	ykaliuta	New Issue
05-07-07 07:22	ykaliuta	Status	new => assigned
05-07-07 07:22	ykaliuta	Assigned To	=> BusyBox
05-07-07 14:51	vda	Note Added: 0002343
05-08-07 09:08	ykaliuta	Note Added: 0002346
05-09-07 14:58	vda	Status	assigned => closed
05-09-07 14:58	vda	Note Added: 0002351
05-09-07 14:58	vda	Resolution	open => fixed

Notes
(0002343) vda 05-07-07 14:51	Actually, GNU awk won't be happy either: # /usr/bin/awk 'END{ printf "%s\n", tttt }' < /dev/null; echo $? awk: fatal: not enough arguments to satisfy format string `%s ' ^ ran out for this one # /usr/bin/awk --version GNU Awk 3.1.5 Copyright (C) 1989, 1991-2005 Free Software Foundation. What do you prefer, nice(r) error msg instead of SEGV? For the record, SEGV happens here: last sprintf gets format "%s" but only one argument "" intead of (int,char) pair it expects. static char awk_printf(node n) { char b = NULL; char fmt, s, f; const char s1; int i, j, incr, bsize; char c, c1; var v, arg; v = nvalloc(1); fmt = f = xstrdup(getvar_s(evaluate(nextarg(&n), v))); i = 0; while (f) { s = f; while (f && (f != '%' \|\| (++f) == '%')) f++; while (f && !isalpha(f)) f++; incr = (f - s) + MAXVARFMT; qrealloc(&b, incr + i, &bsize); c = f; if (c != '\0') f++; c1 = f; f = '\0'; arg = evaluate(nextarg(&n), v); j = i; if (c == 'c' \|\| !c) { i += sprintf(b+i, s, is_numeric(arg) ? (char)getvar_i(arg) : getvar_s(arg)); } else if (c == 's') { s1 = getvar_s(arg); qrealloc(&b, incr+i+strlen(s1), &bsize); // b='' i=0, bsize=443 242 s='%s' s1='' i += sprintf(b+i, s, s1);

(0002346) ykaliuta 05-08-07 09:08	Ok :) $ gawk 'END{printf "%0d%s\n", a, b, c, "aa"}' < /dev/null 0aa $ busybox awk 'END{printf "%0d%s\n", a, b, c, "aa"}' < /dev/null Segmentation fault In any case, I think that yes, the main problem is SIGSEGV.

(0002351) vda 05-09-07 14:58	Minimally fixed in rev 18596 (will error out instead of SEGVing). Thanks.

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