Executing a shell command with redirected IO stops after ~4kb. #352

Trying to transfer a file over base64 (target doesnt have rz or anything like that, thankfully openssl has a base64 en/de/coder), and any large file has its input stop at about the same point, ~4k bytes. After that, the stream stops, as if there was nothing more in standard input.

Steps:

• obtain/generate a file that is over 4.161kb when b64 encoded (I used some random lockfiles I found on my system)
• login through serial to another linux system
• run cat > tmp
• ctrl-t ctrl-R openssl enc -base64 <$FILE
• the stream will stop after less than a second.
• ctrl-c
• note the file size
• run openssl enc -base64 -d <tmp > tmp2, and note the truncated file
• run again, note that the transfer stops at the same point in the file, though the exact point can be different for different files.

Id actually be interested in a reproduction, as I only have acess to a single embedded linux device to test this with, though I also see this with a 'null modem' (a wire shorting the 2 serial lines)