473,899 Members | 3,419 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Listing the most dangerous parts of C

I am looking for a wish list of things which should be removed from
the C (C99) - due to feature's bad security track record <OT>or
Multithreading unsafety. I need this list for a project intending to
build another (easiest & most powerful) programming language, which
has a two page definition document stating: "... includes C
programming language (C99), except its famous
"avoid-using-this-functions". </OT>

If you would not want to remove a whole function but only the use of
it with certain arguments / parameters, what would those combinations
be like? (Like scanf with %s or %[ arguments )

Probably there are official not to use recommendation lists.
( million times better than this)
http://tele3d.com/wiki/index.php/Par...ncluded_in_t3d

Please, do not circumvent the question by saying all functions except
gets() are safe if used properly. That would be like teaching that
"the ideology of Soviet Union was right, it was the Soviet peoples
fault that the system didn't work.

Juuso Hukkanen
(to reply by e-mail set addresses month and year to correct)
www.tele3d.com

May 10 '06 #1
62 4164
Juuso Hukkanen a écrit :
I am looking for a wish list of things which should be removed from
the C (C99) - due to feature's bad security track record <OT>or
Multithreading unsafety. I need this list for a project intending to
build another (easiest & most powerful) programming language, which
has a two page definition document stating: "... includes C
programming language (C99), except its famous
"avoid-using-this-functions". </OT>

If you would not want to remove a whole function but only the use of
it with certain arguments / parameters, what would those combinations
be like? (Like scanf with %s or %[ arguments )

Probably there are official not to use recommendation lists.
( million times better than this)
http://tele3d.com/wiki/index.php/Par...ncluded_in_t3d

Please, do not circumvent the question by saying all functions except
gets() are safe if used properly. That would be like teaching that
"the ideology of Soviet Union was right, it was the Soviet peoples
fault that the system didn't work.

Juuso Hukkanen
(to reply by e-mail set addresses month and year to correct)
www.tele3d.com


What is "t3d" first ???

From that wiki page it is completely imposssible to have an idea what
the hell is that.

jacob
May 10 '06 #2

On Wed, 10 May 2006, jacob navia wrote:
Juuso Hukkanen a écrit :
I am looking for a wish list of things which should be removed from
the C (C99) - due to feature's bad security track record <OT>or
Multithreading unsafety. I need this list for a project intending to
build another (easiest & most powerful) programming language, which
has a two page definition document stating: "... includes C
programming language (C99), except its famous
"avoid-using-this-functions". </OT>

If you would not want to remove a whole function but only the use of
it with certain arguments / parameters, what would those combinations
be like? (Like scanf with %s or %[ arguments )
Probably there are official not to use recommendation lists.
( million times better than this)
http://tele3d.com/wiki/index.php/Par...ncluded_in_t3d


What is "t3d" first ???

From that wiki page it is completely imposssible to have an idea what the
hell is that.


It's vaporware. This guy's been pushing its "natural language, giant
built-in library of functions" model for at least a year or so, now.
(The problems are that the "natural" language isn't, and the "built-in"
functions aren't.)

FWIW, off the top of my head I'd say gets (obviously), strtok (not
thread-safe), atoi (no error-checking possible), and much of scanf
(again with the error-checking).
scanf("%*s") is fine, but scanf("%s") is evil, scanf("%99s") is
unmaintainable, and scanf("%d") chokes in unpredictable ways on input
like "3287482475 ".

my $.02,
-Arthur
May 10 '06 #3
"Juuso Hukkanen" <ju***********@ tele3d.net> wrote in message
news:bm******** *************** *********@4ax.c om...
I am looking for a wish list of things which should be removed from
the C (C99) - due to feature's bad security track record <OT>or
Multithreading unsafety. I need this list for a project intending to
build another (easiest & most powerful) programming language, which
has a two page definition document stating: "... includes C
programming language (C99), except its famous
"avoid-using-this-functions". </OT>

If you would not want to remove a whole function but only the use of
it with certain arguments / parameters, what would those combinations
be like? (Like scanf with %s or %[ arguments )

Probably there are official not to use recommendation lists.
( million times better than this)
http://tele3d.com/wiki/index.php/Par...ncluded_in_t3d

Please, do not circumvent the question by saying all functions except
gets() are safe if used properly. That would be like teaching that
"the ideology of Soviet Union was right, it was the Soviet peoples
fault that the system didn't work.


One very popular wish list is Misra C. (Actuall two, since there's a
revision out too.) It endeavors to tame C by outlawing all sorts of
usages that some people think *might* be misused.

Another is Microsoft's secure/safer/bounded C, a version of which is
now shipping with VC++ V8. It supplies alternatives to many functions
that can be better bounds checked to avoid storage overwrites. This
work is based on Microsoft's massive bug hunt stimulated by all the
viral attacks on Microsoft software largely written in C.

Neither is anywhere near perfect, nor universally accepted. Both are
places to start.

P.J. Plauger
Dinkumware, Ltd.
http://www.dinkumware.com
May 10 '06 #4
Juuso Hukkanen said:
I am looking for a wish list of things which should be removed from
the C (C99)
Absolutely. Just remove C99. Nobody will notice anyway.
- due to feature's bad security track record <OT>or
Multithreading unsafety. I need this list for a project intending to
build another (easiest & most powerful) programming language, which
has a two page definition document stating: "... includes C
programming language (C99), except its famous
"avoid-using-this-functions". </OT>
Okay, drop gets(), scanf(), and strncpy() - ironically, this is unsafe
chiefly because people think it's safe and so they feel free to use it in a
rather cavalier way!

strtok() isn't threadsafe, as someone already said, so I guess you would
want to drop that (I wouldn't, but you're not me).

That's about it, I think. Everything else is fine, if you're careful. (Mind
you, scanf, strncpy, and strtok are fine if you're careful, too!)
Please, do not circumvent the question by saying all functions except
gets() are safe if used properly. That would be like teaching that
"the ideology of Soviet Union was right, it was the Soviet peoples
fault that the system didn't work.


No, it would be more like saying that if you give power tools to
kindergarten kids, you should expect tears before bedtime.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)
May 10 '06 #5

"Juuso Hukkanen" <ju***********@ tele3d.net> wrote in message
news:bm******** *************** *********@4ax.c om...
I am looking for a wish list of things which should be removed from
the C (C99) - due to feature's bad security track record <OT>or
Multithreading unsafety. I need this list for a project intending to
build another (easiest & most powerful) programming language, which
has a two page definition document stating: "... includes C
programming language (C99), except its famous
"avoid-using-this-functions". </OT>

If you would not want to remove a whole function but only the use of
it with certain arguments / parameters, what would those combinations
be like? (Like scanf with %s or %[ arguments )

Probably there are official not to use recommendation lists.
( million times better than this)
http://tele3d.com/wiki/index.php/Par...ncluded_in_t3d
Please, do not circumvent the question by saying all functions except
gets() are safe if used properly. That would be like teaching that
"the ideology of Soviet Union was right, it was the Soviet peoples
fault that the system didn't work.

Juuso Hukkanen
(to reply by e-mail set addresses month and year to correct)
www.tele3d.com


I read a security oriented pdf (sorry, don't know where anymore) which said:

1) 15 C functions suffer buffer overflow problems:
gets() cuserid() scanf() fscanf() sscanf() vscanf() vsscanf() vfscanf()
sprintf() strcat() strcpy() streadd() strecpy() vsprintf() strtrns()

2) 8 C functions suffer from format string vulnerabilities
printf() fprintf() sprintf() snprintf() vprintf() vfprintf() vsprintf()
vsnprintf()

Summary of pdf: Because many C implementations use the same stack for
string data and flow control information (like addresses), the above
functions can modify the flow control information on the stack thereby
allowing authorized code to execute.

If you really want to get crazy with C, do some of these:
1) eliminate pointers in main
2) make pointers be associated with a variable before use, not with a data
type
3) eliminate malloc, add dynamic allocation and garbage collection
4) change C to pass by reference
5) require separation of string (and other) data and flow control
information
6) give up now, and try Walter Bright's D language...
Rod Pemberton
May 10 '06 #6
Rod Pemberton a écrit :

If you really want to get crazy with C, do some of these:
1) eliminate pointers in main
????
2) make pointers be associated with a variable before use, not with a data
type
lcc-win32: done.
References are pointers associated with an object permanently.
3) eliminate malloc, add dynamic allocation and garbage collection
lcc-win32: done.
The gc is standard in the normal distribution.
4) change C to pass by reference
?????
Why?

5) require separation of string (and other) data and flow control
information
Stack allocation is ok if used correctly. Making all objects heap based
would slow done everything without a lot of gain in security.
6) give up now, and try Walter Bright's D language...


????

With the above improvements, C can be much easier and safer to program.

jacob
May 10 '06 #7
"Rod Pemberton" <do*********@bi tfoad.cmm> writes:
[...]
I read a security oriented pdf (sorry, don't know where anymore) which said:

1) 15 C functions suffer buffer overflow problems:
gets() cuserid() scanf() fscanf() sscanf() vscanf() vsscanf() vfscanf()
sprintf() strcat() strcpy() streadd() strecpy() vsprintf() strtrns()

[snip]

Obviously this document wasn't concerned just with standard C. A
number of those functions are non-standard. (I haven't even heard of
all of them.)

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.
May 10 '06 #8
On Wed, 10 May 2006 16:25:42 +0000, Richard Heathfield wrote:
Okay, drop gets(), scanf(), and strncpy() - ironically, this is unsafe
chiefly because people think it's safe and so they feel free to use it in a
rather cavalier way!
Ok, strncpy gone. I too I was unsure about it after reading the
http://en.wikipedia.org/wiki/Strlcpy
, but I thought to keep the strncpy for the sake of respect of
standard libraries :)
I see strlcpy could be obtained from the kind donation public
domain by Chuck Falconer, but I am not sure if it is a good idea to
have non-standard C functions inserted. Possible strlcpy is soon part
of the standard.
strtok() isn't threadsafe, as someone already said, so I guess you would
want to drop that (I wouldn't, but you're not me).


Well also the strtok(), (and even gets()) problems see to have better
but still a non-standard solutions provided to public domain by Chuck
(hmmm. Do I see a pattern) .

toksplit()
http://groups.google.com/group/comp....2e03ab0f27f874
ggets()
http://cbfalconer.home.att.net/download/ggets.zip

Thanks for the suggestions
Juuso Hukkanen
(to reply by e-mail set addresses month and year to correct)
www.tele3d.com
May 10 '06 #9
On Wed, 10 May 2006 12:56:23 -0400, "Rod Pemberton"
<do*********@bi tfoad.cmm> wrote:
1) 15 C functions suffer buffer overflow problems:
gets() cuserid() scanf() fscanf() sscanf() vscanf() vsscanf() vfscanf()
sprintf() strcat() strcpy() streadd() strecpy() vsprintf() strtrns()

2) 8 C functions suffer from format string vulnerabilities
printf() fprintf() sprintf() snprintf() vprintf() vfprintf() vsprintf()
vsnprintf()
It's probably this document
http://www.ida.liu.se/~johwi/researc...ate_thesis.pdf
Chapter 7.3.3 Functions which are for attracting buffer overflows
Chapter 7.3.5 Format string vulnerabilities

very good reading , and it gives references to another even better
says...

<snip>
Functions to avoid in most cases (or ensure protection) include the
functions, strcpy(3), strcat(3), sprintf(3) (with cousin vsprintf(3)),
and gets(3). These should be replaced with functions
such as strncpy(3), strncat(3), snprintf(3), and fgets(3)
respectively, but see the discussion below. The
function strlen(3) should be avoided unless you can ensure that there
will be a terminating NIL character to
find. The scanf() family (scanf(3), fscanf(3), sscanf(3), vscanf(3),
vsscanf(3), and vfscanf(3)) is often
dangerous to use; do not use it to send data to a string without
controlling the maximum length (the format %s
is a particularly common problem).
....
Unfortunately, snprintf()'s variants have additional problems.
Officially, snprintf() is not a standard C function
in the ISO 1990 (ANSI 1989) standard, though sprintf() is, so not all
systems include snprintf(). Even worse,
some systems' snprintf() do not actually protect against buffer
overflows; they just call sprintf directly.
</snip>
http://www.dwheeler.com/secure-progr...rams-HOWTO.pdf
If you really want to get crazy with C, do some of these:
1) eliminate pointers in main
2) make pointers be associated with a variable before use, not with a data
type
3) eliminate malloc, add dynamic allocation and garbage collection Eliminated by including the Boehms garbage collector4) change C to pass by reference Done in a way that inputs go into functions with values and results
are taken out from the functions by pass by references (or its C
equivalent)5) require separation of string (and other) data and flow control
information The "safe strings" have the first 100 bytes header information about
and for each arrays life, the debug mode collects info from each
function entry - exit. All functions return long long negative values
meaning intelligent error codes.
6) give up now, and try Walter Bright's D language...


D is gainning ground,
http://www.tiobe.com/tiobe_index/index.htm

Because it has everything
http://www.digitalmars.com/d/comparison.html

Well I bet their language definition is bigger than two pages and it
can not be learned in 30 minutes :)
www.tele3d.com/t3d/language.pdf

Thank You
Juuso Hukkanen
(to reply by e-mail set addresses month and year to correct)
www.tele3d.com
May 10 '06 #10

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

4
1898
by: Chris | last post by:
Hello Am really worried, so wondered if anyone could help. My site outgrew itself recently so we've had to make changes to the url structure. I have some important url's like this: www.mysite.com/bluewidgets/, Yet now with the expansion of the site and url structure change (had to be done) we also have urls like: www.mysite.com/country1/bluewidgets/ which serves up identical content to the above first url.
3
1546
by: Mr. B | last post by:
In my application which allows a user to open specific AutoCAD script files (SCR extension), I want to intoduce a listing of the 10 most recently opened files. I know of at least two ways that I could do this: 1) Have a text file that contains the information 2) Write the info to the Registry The first is my easiest as I am familiar with TXT type files. I've never used (and have no idea how to use) a XML type file (let alone the...
3
3105
by: David Callaghan | last post by:
Hi I've just joined tesco broadband. I've come from NTL. If I don't put an index.htm on my NTL home page it justs lists the files in there when any browser visites my page. If I don't put an index.htm on my Tesco home page, I get a:
0
1604
by: kristopher | last post by:
Websites of various subjects ranging from computing to entertainment. TrafficRanking.com says that allsitecafe.com is one of the most VISITED internet sites on the web today! There are over 1,700+ sites linked to allsitecafe.com, and every site has been visited by a human being before inclusion into the allsitecafe.com database of links. You won’t find many dead links at allsitecafe.com – the database is faithfully updated every 4-6 months...
2
2917
by: cj | last post by:
Hi, I'm able to get the listing of (or "Index of") a directory on a website/webserver using HttpWebRequest and HttpWebResponse, but it comes back as an HTML page, similar to what IE or Mozilla/Firefox/Netscape would show. Is there anyway to get the listing in some other form, or do I just have to parse the info myself?
7
4755
by: JohnR | last post by:
Couldn't find it in MSDN. Does anybody have a listing of the message constants that would be received in my application.addmessagefilter routine in VB.net? They are referred to all over MSDN but I can't locate the actual listing of the constants and their values. Thanks, John
1
3380
by: Light | last post by:
Re, I'm having 2 problems with the Telerik trial controls. I'm using the latest release. I'm using 2005 studio and most of the controls show up properly in the designer but the RadMenu does not. It says "Error Creating Control" and then a ton of errors. This occurs both when I use it and in the examples but it does render properly when built. If I drag/drop the control then it shows up properly but when I apply a theme and then...
2
3275
by: Juuso Hukkanen | last post by:
I need a list of multithreading unsafe C (C99) functions/features. comp.programming.threads provided an initial list of C:ish functions, with following ANSI C functions: asctime, gmtime, localtime, ctime, tmpnam, strtok http://www.lambdacs.com/cpt/FAQ.html#Q150 However, extra Googling hinted rand() and srand(), also being unsuitable for multi-threading - opinions? And what is the status of
1
1341
by: TahoeKid | last post by:
I need to modify and assemble the assembler listing files generated from the VS 2005 IDE. A test generated listing file did not assmeble 'as is'. Has anyone tried this? It seems to me the listing file should assemble.
0
9997
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...
0
9845
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
0
10866
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
1
10976
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
1
8043
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms. Adolph will...
0
7204
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
5891
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
0
6082
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
3
3320
bsmnconsultancy
by: bsmnconsultancy | last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.