Hi,

I am trying to tighten file I/O security on a process that passes a
user-supplied script to R CMD Batch.  Broadly speaking, I'd like to restrict
I/O to a designated path on the file system. Right now, I'm trying to
address this in the R environment by forcing the script to use modified
versions of scan, read.table, sys.load.image, etc.

I can run a replace string on the user-supplied script so that, for example,
"scan(" is replaced by "safe.scan("

e.g.

> SafePath <- function(file)
{fp<-strsplit(file,"/");paste("safepath",fp[[1]][length(fp[[1]])],sep="/")}
> SafePath("/etc/passwd")
[1] "safepath/passwd"

>  Safe.scan <- function(file, ...) scan(SafePath(file),...)
> Safe.scan("/etc/passwd",what="",sep="\n")
Error in file(file, "r") : unable to open connection
In addition: Warning message:
cannot open file 'safepath/passwd', reason 'No such file or directory'

I'd appreciate any critique of this approach.  Is there something more
effective or elegant?

Regards,
Mike

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