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Merge pull request #252 from xexyl/1994-shapiro

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Updates to 1994/shapiro including possible bug
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Landon Curt Noll authored and GitHub committed 2023-04-02 16:24:54 -07:00
2 parents 1afd85d2cc f2998adcab
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1994/shapiro/Makefile
+1 -1
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@@ -109,7 +109,7 @@ ENTRY= shapiro
PROG= ${ENTRY}
#
OBJ= ${PROG}.o
DATA= shapiro.info
DATA= shapiro.md
TARGET= ${PROG}
#
ALT_OBJ=
1994/shapiro/README.md
+78 -44
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@@ -1,62 +1,96 @@
# Most Well Rounded Obfuscation:
Andrew T. Shapiro
CSES/CIRES University of Colorado
Campus Box 216
Boulder, CO 80309-0216
USA
Andrew T. Shapiro
CSES/CIRES University of Colorado
Campus Box 216
Boulder, CO 80309-0216
USA
## To build:
make all
## To run
[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) pointed out a potential
bug on systems where `EOF != -1`. The problem is that `getc()` and the related
functions do not return `-1` on EOF or error but rather `EOF` but the program
assumes `-1` (conversely when using the `getopt()` functions one should not
check for EOF but -1 as the functions return -1 not EOF but the standard does
not require `EOF` to be -1, just a negative number. However changing it to check
for `!=EOF` caused a problem due to the clever encoding of the code. See
[bugs.md](/bugs.md) for more details if you wish to try and fix this (Cody is
here and there working on it along with other things and will change this
message when it's fixed assuming it's feasible).
## To run:
./shapiro &
## Judges' comments
## Try:
This entry has many different levels of obfuscation, and yet the
source file is self documenting. :-)
```sh
./shapiro
^Z
bg
ps x
^C
From time to time, run ps and look at the new processes.
./shapiro_t1
```
See shapiro.info for more information in the internals of this program.
The file shapiro.alt contains a non-obfuscated version of this program.
Notice what you see in the output of `ps`!
## Author's comments
The basic theme (pun) of this program is:
"This time (everything) is not where it should be."
~~~~
My entry (shapiro.c) is mostly comment, formatted in the shape of a
clock. If you strip out the comments and look at the code you will
quickly realize that the comments were the important part and that
the code does very little (see pun above). It writes (to stdout)
another C program (shapiro_t2.c). This is the first level of
obfuscation.
The second program (shapiro_t2.c if you use the build/make file)
prints a clock in the upper right hand corner of your VTxxx/ANSI
display.
Most of the surface obfuscation in the second program (shapiro_t2.c)
was an attempt to make it as small as possible. You should be able to
see around this with cb(1) and some more intelligent variable names.
Once you get past this you will realize that the third level of
obfuscation is a six member client/server hierarchy.
(See the second info file for a detailed description of the algorithm.)
Lint complains about: precedence confusion, K may be used before set,
main() returns random value to invocation environment, value type used
inconsistently, value type declared inconsistently, function argument
( number ) used inconsistently, function returns value which is always
ignored, function returns value which is sometimes ignored
All of which are harmless (famous last words).
This may or may not work on non ASCII systems (I could not find one to
test it on.)
## Judges' comments:
This entry has many different levels of obfuscation, and yet the
source file is self documenting. :-)
From time to time, run ps and look at the new processes.
See [shapiro.md](shapiro.md) for more information in the internals of this program.
The file [shapiro.alt.c](shapiro.alt.c) contains a non-obfuscated version of
this program. Note that this alt file is currently missing. See
[bugs.md](/bugs.md) for details.
## Author's comments:
The basic theme (pun) of this program is:
> "This time (everything) is not where it should be."
> ~~~~
My entry ([shapiro.c](shapiro.c)) is mostly comment, formatted in the shape of a
clock. If you strip out the comments and look at the code you will
quickly realize that the comments were the important part and that
the code does very little (see pun above). It writes (to stdout)
another C program ([shapiro_t2.c](shapiro_t2.c)). This is the first level of
obfuscation.
The second program ([shapiro_t2.c](shapiro_t2.c) if you use the Makefile
prints a clock in the upper right hand corner of your VTxxx/ANSI display.
Most of the surface obfuscation in the second program
([shapiro_t2.c](shapiro_t2.c))
was an attempt to make it as small as possible. You should be able to
see around this with cb(1) and some more intelligent variable names.
Once you get past this you will realize that the third level of
obfuscation is a six member client/server hierarchy.
(See the [shapiro.md](shapiro.md) file for a detailed description of the
algorithm.)
Lint complains about: precedence confusion, `K` may be used before set,
main() returns random value to invocation environment, value type used
inconsistently, value type declared inconsistently, function argument
(number) used inconsistently, function returns value which is always
ignored, function returns value which is sometimes ignored.
All of which are harmless (famous last words).
This may or may not work on non ASCII systems (I could not find one to
test it on.)
## Copyright and CC BY-SA 4.0 License:
1994/shapiro/shapiro.info
-109
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@@ -1,109 +0,0 @@
HINTS
~~~~~
For the first program (prog.c):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is a very simple program:
1. #include <stdio.h>
2. main()
3. {
4. int K,L,M=0;
5. FILE *J;
6. J=fopen(__FILE__,"r");
7. for(;
8. (L=getc(J))!=-1;
9. L>='J'&&L<='J'+15 &&
10. ((M=!M)?K=L:putchar(K-'J'|(L-'J'<<4)))
11. );
12. exit(0)}
Lines 1-5 are basic stuff. Line 6 opens the source code for input. Line 7
is the loop. Line 8 is read in each character in the file (placed in L)
while not EOF(-1). Line 9 is an if expression which filters out all
characters not between J and J + 15. Line 10 uses M to execute two different
paths the first just stores the character in K. The second path combines
the last two characters read in as high and low nibbles of a byte and
outputs them. In effect this is a very poor ASCII to binary decoder.
The last line is necessary so that make will not stop when it executes
this program.
The second program is encoded into this format and then included (mostly)
as a comment.
Notice that it is impossible to write this program while leaving 16
contiguous ASCII characters free for the encoding. Because of this the
second program is mostly included as a comment. However, some of the
characters of the encoded program are also source code for the decoder.
For the second program (time.c):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 #include <stdio.h>
2 #include <time.h>
3 #define o(j,k,m,n,l) {fprintf(j,a[k],m,n,a[l]);fflush(j);}
4 char *a[]={"%c+------------+\n","%c+%3d %-8s+\n","seconds","minutes",
5 "hours","%s\n","\0337\033[%d;65;H%s\0338"};
6 int b[]={0,0,17,14,11,0};
7 main(v,c)
8 int v;
9 char ** c;
10 {
11 char d[40],*e,f=6;
12 time_t g;
13 FILE *h,*i;
14 while (--f && !pipe(d) && !fork());
15 h=fdopen(6-f<<1,"a");
16 i=fdopen((6-f<<1)+1,"r");
17 for(;;){
18 if(f){
19 fgets(d,40,i);
20 d[strlen(d)-1]='\0';
21 if(*d=='0'+f){ sprintf(*c,"%s\n",d+1); o(stdout,6,6-f,d+1,0) }
22 if(*d>'0'+f) o(h,5,d,0,0)
23 }else{
24 time(&g);
25 e=asctime(localtime(&g));
26 for(v=1;v<6;v++) o(h,v!=1&&v!=6-1,v+'0',atoi(e+b[v]),v)
27 sleep(1);
28 }}}
Lines 1 and 2 have to be. Think of 'o' in line 3 as send message with
j,k and m as where, format and what. Lines 4 and 5 are all the text
strings. Line 6 is the offsets into the time string for the hours,
minutes and seconds. Lines 7-13 are basic stuff. Line 14 is the crux of
the biscuit. 14 forks off 'f'(6) processes each of which is connected to
the ones above and below it with a Unix pipe. It was too difficult to
recover the actual fd numbers for the pipe ends in line 14 so I regenerate
them and fdopen them (for use with the standard C library functions) on lines
15 and 16. Now we have six almost identical processes. Each of which has
two files open h and i (up and down). The only difference in each process
is the value of f (0 <= f < 6). The five processes where f !=0 are the
slave processes and f == 0 is the master. Line 17 says we are going to do
this forever. Lines 18 and 23 differentiate between the master and the
slaves.
Lines 19 to 22 are the slave code. Here we read in a line of text from
i (down)(line 19) and remove the end of line char (line 20). On line
21 if this message is for us (if the first character is our number, f,
in ASCII) we do two things:
1. We copy the text of the message to *c which is really argv[0].
If you are on the correct flavor of Unix this will change the output of
the ps(1) command to the string we just put there.
2. We send the message (not including the number) to stdout with
format number 6 ("\0337\033[%d;65;H%s\0338") If you can read VTxxx
(and I read books printed as ANSI/VTxxx codes for fun :-) you know this
is the sequence for: remember where we are,
go somewhere else,
print the message,
and return to where we started.
Line 22 says if this message is not for us (the number is bigger than ours)
send it to h (up).
Lines 24 to 27 are the master code. Here we get the time and convert it
to an ASCII format (lines 24 and 25). Then on line 26 we build and send
each of the messages for the slaves. The message uses a different control
string for the different slaves. For the first and last slave the message
text is just "%c+------------+\n" (slave number, text, newline.) For the
other slaves it is "%c+%3d %-8s+\n" (slave number, number, units, newline).
The slave number is v+'0'. The number (if used) is atoi(e+b[v]) and the
units are just the string in the slave number position.
1994/shapiro/shapiro.md
+118
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@@ -0,0 +1,118 @@
# HINTS
For the first program (prog.c):
This is a very simple program:
```
1. #include <stdio.h>
2. main()
3. {
4. int K,L,M=0;
5. FILE *J;
6. J=fopen(__FILE__,"r");
7. for(;
8. (L=getc(J))!=EOF;
9. L>='J'&&L<='J'+15 &&
10. ((M=!M)?K=L:putchar(K-'J'|(L-'J'<<4)))
11. );
12. exit(0);}
```
Lines 1-5 are basic stuff. Line 6 opens the source code for input. Line 7
is the loop. Line 8 is read in each character in the file (placed in `L`)
while not `EOF` (usually `-1`). Line 9 is an if expression which filters out all
characters not between `J` and `J + 15`. Line 10 uses `M` to execute two different
paths the first just stores the character in `K`. The second path combines
the last two characters read in as high and low nibbles of a byte and
outputs them. In effect this is a very poor ASCII to binary decoder.
The last line is necessary so that make will not stop when it executes
this program.
The second program is encoded into this format and then included (mostly)
as a comment.
Notice that it is impossible to write this program while leaving 16
contiguous ASCII characters free for the encoding. Because of this the
second program is mostly included as a comment. However, some of the
characters of the encoded program are also source code for the decoder.
### For the second program (with time.h):
```
1 #include <stdio.h>
2 #include <time.h>
3 #define o(j,k,m,n,l) {fprintf(j,a[k],m,n,a[l]);fflush(j);}
4 char *a[]={"%c+------------+\n","%c+%3d %-8s+\n","seconds","minutes",
5 "hours","%s\n","\0337\033[%d;65;H%s\0338"};
6 int b[]={0,0,17,14,11,0};
7 main(v,c)
8 int v;
9 char ** c;
10 {
11 char d[40],*e,f=6;
12 time_t g;
13 FILE *h,*i;
14 while (--f && !pipe(d) && !fork());
15 h=fdopen(6-f<<1,"a");
16 i=fdopen((6-f<<1)+1,"r");
17 for(;;){
18 if(f){
19 fgets(d,40,i);
20 d[strlen(d)-1]='\0';
21 if(*d=='0'+f){ sprintf(*c,"%s\n",d+1); o(stdout,6,6-f,d+1,0) }
22 if(*d>'0'+f) o(h,5,d,0,0)
23 }else{
24 time(&g);
25 e=asctime(localtime(&g));
26 for(v=1;v<6;v++) o(h,v!=1&&v!=6-1,v+'0',atoi(e+b[v]),v)
27 sleep(1);
28 }}}
```
Lines 1 and 2 have to be. Think of `o` in line 3 as send message with
`j`,`k` and `m` as where, format and what. Lines 4 and 5 are all the text
strings. Line 6 is the offsets into the time string for the hours,
minutes and seconds. Lines 7-13 are basic stuff. Line 14 is the crux of
the biscuit. 14 forks off `f` (6) processes each of which is connected to
the ones above and below it with a Unix pipe. It was too difficult to
recover the actual FD numbers for the pipe ends in line 14 so I regenerate
them and `fdopen()` them (for use with the standard C library functions) on lines
15 and 16. Now we have six almost identical processes. Each of which has
two files open `h` and `i` (up and down). The only difference in each process
is the value of `f` (`0 <= f < 6`). The five processes where `f !=0` are the
slave processes and `f == 0` is the master. Line 17 says we are going to do
this forever. Lines 18 and 23 differentiate between the master and the
slaves.
Lines 19 to 22 are the slave code. Here we read in a line of text from
`i` (down)(line 19) and remove the end of line char (line 20). On line
21 if this message is for us (if the first character is our number, `f`,
in ASCII) we do two things:
1. We copy the text of the message to `*c` which is really argv[0]. If you are
on the correct flavor of Unix this will change the output of the `ps(1)` command
to the string we just put there.
2. We send the message (not including the number) to stdout with format number 6
(`"\0337\033[%d;65;H%s\0338"`) If you can read VTxxx (and I read books printed
as ANSI/VTxxx codes for fun :-) ) you know this is the sequence for:
remember where we are,
go somewhere else,
print the message,
and return to where we started.
Line 22 says if this message is not for us (the number is bigger than ours)
send it to `h` (up).
Lines 24 to 27 are the master code. Here we get the time and convert it
to an ASCII format (lines 24 and 25). Then on line 26 we build and send
each of the messages for the slaves. The message uses a different control
string for the different slaves. For the first and last slave the message
text is just `"%c+------------+\n"` (slave number, text, newline.) For the
other slaves it is `"%c+%3d %-8s+\n"` (slave number, number, units, newline).
The slave number is `v+'0'`. The number (if used) is `atoi(e+b[v])` and the
units are just the string in the slave number position.
bugs.md
+100 -3
View File
@@ -522,13 +522,13 @@ If you join the lines you end up with:
If you look at column 25 which is the end of the word 'mh111' and you go down to
the next row you'll see a 0 and if you go one row down another 0. This is the
buffer size, 100, for `u`. The column to the left is the same for the `t`
buffer size, 100, for `u`! The column to the left is the same for the `t`
variable.
Thus it seems that in order to get the generated output correct one needs to
provide the correct input in comments or possibly by rearranging some of the
code (this was required to make the generated code compile at all when changing
the buffer size).
code (this was actually required to make the generated code compile at all when
changing the buffer size, see below).
### Important points:
@@ -550,6 +550,103 @@ can cause a compilation error! Make sure that the output of:
can be compiled and the output of that new program when fed itself can also be
compiled!
## [1994/shapiro](1994/shapiro/shapiro.c) ([README.md](1994/shapiro/README.md))
## STATUS: missing file - please provide it
[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) noted that the
README.md file refers to an alternative version of the code that is not
obfuscated but it is missing from the entry directory and the archive. Do you
have this file?
We would be grateful if you could provide it to us. If you can provide this
file you might consider removing this entry from this file as well but if not
we'll take care of it.
### Important reminder to fix the `-1` value check for `getc()`:
Cody wants to remind you that he fixed the code to not use `-1` for the return
value of `getc()`; this is important because `EOF` is **NOT** guaranteed to be
`-1` but rather any negative value. On systems where `EOF != -1` the program
would enter an infinite loop until the program crashed, by chance reads a `-1`
or was killed. See the README.md for more details. If you don't feel comfortable
changing it to `EOF` Cody will happily do it for you but otherwise go right
ahead. We'll credit you in the README.md file regardless.
## STATUS: doesn't work with some platforms - please help us fix
[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) pointed out a potential
bug in [1994/shapiro](1994/shapiro/shapiro.c) on systems where `EOF != -1` as
the code assumes that `EOF` will always be `-1`. As the standard says (see `7.21
Input/output<stdio.h>` subsection 1) it only has to be a negative int, not
necessarily `-1`. The problem is that the source file's last character is a
newline (10 in decimal) and so on systems where `EOF != -1` the `getc()`
functions would not terminate the loop (but see below). This would cause a
breakage in the entry.
However due to clever encoding of the code it is not a simple matter of applying
the following patch:
```diff
diff --git i/1994/shapiro/shapiro.c w/1994/shapiro/shapiro.c
index d2da120c7bc4e251b7624859e48f47f188d398e9..e054a1ceb067b82bf37c07e5ce75e82be7a03b85 100644
--- i/1994/shapiro/shapiro.c
+++ w/1994/shapiro/shapiro.c
@@ -9,11 +9,11 @@
/*PPPPVPOQMQRPR*/=0;FILE/*TPSLUMWQT*/ *
J/*MPRPKPLQ*/; J= fopen(__FILE__
/*T*/,"r");for (;( L/*KPUOWOWMUQ
LLOLMPULWLWL WLW LWLWLWLWLWLW
LWLWLULVOXP LLV LLLOLMPULOL
- MMNP*/=getc (J) )!= -1;L/*
+ MMNP*/=getc (J) )!=EOF;L/*
OLWLRMMQUL VOX PLLVLLLMQO
PMPYPXPNP MQL LVLLLWPSP
XPOQNQOPMQ LLV LTj*/>='J'
&&L/*LRPYP OQL QMQLLVLLL
OLMQVOXPL LVL LLVOe*/<=
```
as doing so will cause `warning: illegal character encoding in string
literal` and the error `error: source file is not valid UTF-8`. Looking at the
file you'll see on line 4 of `shapiro_t2.c`:
```
char *a[]={"%c+------------+\n","%c+%3dPRÒ<82>3·Âå&Â"2W6öæF6'Â"Ò<96>æVGW6'¢ <82>öV'7'Â"R2Çå&Â"Â^E33sÃ^E33³UB¶cS³<83>T2Ç^E33<83>#Ò·£<90>æF^G"¶ÕÕ³^GÃ^BÃ^RsÃ^RCÃ^R^SÃ^BÓ·£Ð^V<96>æ<86>bÇ2<96><92>æF^Gb·3<86>^V&^G¢¢^B2¶£°7<86>^V&^GB¶E^CÓÅ¢RÆbÖc³£@<97>ÖVöE^Gr¶£`<94>ÄT^D¢<82>Æ¢<92>¶£p<87><96>ÆV^F<82>ÒÒb^Fbb^B^R^B<97>^FW<86>B<96>^Bbb^B^Rbö&·<86><92><92>²£<80>ÖcFö^FWæ<86>bÓbÆÃ^SÃ"^R&<92>²<93>ÖcFö^FWæ<86><82>bÓbÆÃ^S<93>²^RÃ""'<92>²£`ö&<87>²³<93>²<97>f<86>b<96>²gvVF7<87>BÆB^CÃ<92><96>²C¶5G'ÇVæ<86>B<96>Ò^RÓÕsÂ^Es²£<90>f<86>¢BÖÓs^Bs²b<96>²7^G'<97>æFg<86>¢2Æ"R2Çå&ÂB¶^R<93>²ó<86>2GGöVGÇbÃbÓbÆB¶^RÃ^B<93>Ò§<90>f<86>¢Bæs^Bs²b<96>ò<86><82>ÆRÃBÆ^BÃ^B<93>ÒWÆ6W¶G<97>ÖV<86>br<96>²SÖ^S67F<97>ÖV<86>Âö6^VÆF<97>ÖV<86>br<96><92>²£`ö&<87>b×^S³cÇc³c·²<92>ò<86><82>Æb^WÒ^Scbb^WÒcÓ^RÃb·r^BsÂ^RF÷<96><86>R¶"¶e×<95>Âb<97>2ÇVV^F<87>^R<93>²Ó×ק 
```
when it should be something entirely different. For what it should be try
running `make clobber all ; cat shapiro_t2.c` or else look at the second program
in the spoilers file [shapiro.md](1994/shapiro/shapiro.md]).
Cody is working will be working on this here and there but if you have a fix or
any suggestions you're welcome to provide it or them.
Cody points you to the README.md file for what should happen when the entry is
successfully compiled (including no compilation errors when running `make
clobber all`).
Another problem is that in the [shapiro.md](shapiro.md) file the first program
does not work.
### Tips on this entry:
Cody provides some tips on this entry:
First: the comments are the important part of this entry. Remove them and the
program breaks.
Second and perhaps part of the problem with changing the code to `EOF` instead
of `-1` is the `for` loop particularly to do with the bitwise operations,
perhaps also made worse by the seemingly gibberish comments.
Another important point is that the Makefile compiles the program as
`shapiro_t1` so that the source code that corresponds with it is actually
[shapiro.c](1994/shapiro/shapiro.c). But notice how running `shapiro_t1` results
in different functionality than `shapiro` itself? The source code that
`shapiro_t1` generates, `shapiro_t2.c`, is what is compiled into `shapiro`.
# 1995