Now imagine if someone fed it `find /dev -type b -exec dd if=/dev/urandom of={}`.
I don't want my strings to be able to execute arbitrary code like this.
If you put that into the string variable and execute the line I posted, nothing will happen other than the tokens being placed into the positional parameters. The code in $string will not be executed.
How do you pass parameters over to another script and run the receiving script? .
Here is an example of what I am talking about.
for x in `cat Allx`
do
su myaccount -c "/temp/scripts/temp_script $x" > /dev/null 2>$1 $
done
I was expecting the tem_script to be... (1 Reply)
Hi:- I need to parse a script 3 parameters (file, subject and email address). This is what I currently have:
allargs=$*
argcount=`echo $allargs | awk -F: '{ print NF }' ` # Total Number of arguments
pdffile=`echo $allargs | awk -F: '{ print $1 }' ` # PDF/binary file to be encoded... (4 Replies)
Sceduled backups with vdump have been delayed as a mounted system had crashed while I was away for 2 weeks. Now there are 5 simultaneous vdumps running very slowly. The full system backup usually takes a whole weekend.
Can I safely kill these? (I will have to live without a backup untill next... (4 Replies)
I have a job script that runs with input parms from the command line.
job.sh -p parm1_parm2_parm3_parm4_file_1.dat
The parms are separated by _
The last parm is a file name and can have an _ in the name.
I currently use the following commands to extract the parms
parm1=`eval echo... (3 Replies)
Hi all,
Am writing a script that does a rm/mv if a file exist, however, in one scenario, one of the variables which is supposed to a variable for a directory is undefined/blank so instead of the variable resolving to /tmp/logfile.dmp, it resolves instead to / so the rm translates to a rm /... (2 Replies)
I get a strange problem here, and ask for help.
(gdb)
28 set_file_bit( file, bytePos, bitPos, argv );
(gdb) p argv
$3 = 0xbfffef5c "00"
(gdb) s
set_file_bit (file=0x804b008, bytePos=2, bitPos=2, binary=0x80490e5 "11") at util/file.c:112
... (2 Replies)
Greetings,
I need some help performing a system admin function that I have been tasked with. The request seems simple enough, but my feeling is that it might be more complicated than it seems.
Here is what i've been tasked with:
SunOS 5.10 Generic_142900-15 sun4u sparc SUNW,SPARC-Enterprise... (3 Replies)
I am using:
reboot -- cdrom
However I'm afraid of causing file system errors/corruption. I've seen many threads say that
init 6
is safer, but I need to get to CDROM.
Is there a command that is as safe as init, but can boot to cdrom, or should I not worry so much about the reboot... (5 Replies)
I wanted to know whether all files under /tmp can be safely removed. I guess that /tmp may also have temporary files for applications currently being worked on, so at the most those applications may just shut down.
I hope that my question is clear whether all files under /tmp can be safely... (5 Replies)
Discussion started by: RHCE
5 Replies
LEARN ABOUT OPENDARWIN
urandom
RANDOM(4) BSD Kernel Interfaces Manual RANDOM(4)NAME
random , urandom -- random data source devices.
SYNOPSIS
pseudo-device random
DESCRIPTION
The random device produces uniformly distributed random byte values of potentially high quality.
To obtain random bytes, open /dev/random for reading and read from it.
To add entropy to the random generation system, open /dev/random for writing and write data that you believe to be somehow random.
/dev/urandom is a compatibility nod to Linux. On Linux, /dev/urandom will produce lower quality output if the entropy pool drains, while
/dev/random will prefer to block and wait for additional entropy to be collected. With Yarrow, this choice and distinction is not necessary,
and the two devices behave identically. You may use either.
OPERATION
The random device implements the Yarrow pseudo random number generator algorithm and maintains its entropy pool. Addditional entropy is fed
to the generator regularly by the SecurityServer daemon from random jitter measurements of the kernel. SecurityServer is also responsible
for periodically saving some entropy to disk and reloading it during startup to provide entropy in early system operation.
You may feed additional entropy to the generator by writing it to the random device, though this is not required in a normal operating envi-
ronment.
LIMITATIONS AND WARNINGS
Yarrow is a fairly resilient algorithm, and is believed to be resistant to non-root. The quality of its output is however dependent on regu-
lar addition of appropriate entropy. If the SecurityServer system daemon fails for any reason, output quality will suffer over time without
any explicit indication from the random device itself.
Paranoid programmers can counter-act this risk somewhat by collecting entropy of their choice (e.g. from keystroke or mouse timings) and
seeding it into random directly before obtaining important random numbers.
FILES
/dev/random
/dev/urandom
HISTORY
A random device appeared in Linux operating system.
Darwin September 6, 2001 Darwin