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Add a check that the file descriptor mentioned in a N> or N< type

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redirect operator is within range of what the code tree node can
hold.   Currently this is a no-op change (the new error can never
occur) as the code already checks that N is in range for an int
(and errors if not) and the field in the node in which we store N
is also an int, so we cannot overflow - but fd's do not really need
to be that big (the max a typical kernel supports is < 10000) so
this just adds validation in case it ever happens that we decide we
can save some node size (ie: sh memory) by making that field smaller.

Note this is parse time error detection, and has no bearing upon
the execution time error that will occur if a script attempts to use
an fd that exceeds the process's max fd limit.

NFCI (for now anyway.)
This commit is contained in:
kre 2019-02-09 09:50:31 +00:00
parent 83735e242c
commit 4d2988311a
1 changed files with 10 additions and 5 deletions
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15
bin/sh/parser.c
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@ -1,4 +1,4 @@
/* $NetBSD: parser.c,v 1.165 2019/02/04 11:16:41 kre Exp $ */
/* $NetBSD: parser.c,v 1.166 2019/02/09 09:50:31 kre Exp $ */
/*-
* Copyright (c) 1991, 1993
@ -37,13 +37,14 @@
#if 0
static char sccsid[] = "@(#)parser.c 8.7 (Berkeley) 5/16/95";
#else
__RCSID("$NetBSD: parser.c,v 1.165 2019/02/04 11:16:41 kre Exp $");
__RCSID("$NetBSD: parser.c,v 1.166 2019/02/09 09:50:31 kre Exp $");
#endif
#endif /* not lint */
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include "shell.h"
#include "parser.h"
@ -1569,9 +1570,13 @@ parseredir(const char *out, int c)
union node *np;
int fd;
fd = (*out == '\0') ? -1 : number(out);
np = stalloc(sizeof(struct nfile));
fd = (*out == '\0') ? -1 : number(out); /* number(out) >= 0 */
np->nfile.fd = fd; /* do this again later with updated fd */
if (fd != np->nfile.fd)
error("file descriptor (%d) out of range", fd);
VTRACE(DBG_LEXER, ("parseredir after '%s%c' ", out, c));
if (c == '>') {
if (fd < 0)