When piping data to a command in bash, can other processes snoop on the data?

Question

An example of this is:

cat pass.txt | docker login -u jarjarbinks --password-stdin=true

Can another unprivileged process snoop on the data being transferred through the anonymous FIFO?

`cat pass.txt | docker` is a typical [useless use of cat](https://stackoverflow.com/q/11710552/7939871) — Léa Gris, Oct 15 '21 at 05:26

Marcus Müller · Accepted Answer · 2021-10-14T23:29:02.567

does the process belong to the same user running this?

YES: well, just as you can attach a debugger to your own processes, another process run by your user (assuming you have the SYS_PTRACE capability, but you usually do) can just snoop on the system calls needed to read the stdin file descriptor.
NO: "standard" unix user separation applies and the other user can't interfere with your processes, their memory or file descriptors.

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