This ended up more complicated then expected. Lets start first with the
problem to show why I am doing this:
Currently we simply execute ps(1) in the container. This has some
drawbacks. First, obviously you need to have ps(1) in the container
image. That is no always the case especially in small images. Second,
even if you do it will often be only busybox's ps which supports far
less options.
Now we also have psgo which is used by default but that only supports a
small subset of ps(1) options. Implementing all options there is way to
much work.
Docker on the other hand executes ps(1) directly on the host and tries
to filter pids with `-q` an option which is not supported by busybox's
ps and conflicts with other ps(1) arguments. That means they fall back
to full ps(1) on the host and then filter based on the pid in the
output. This is kinda ugly and fails short because users can modify the
ps output and it may not even include the pid in the output which causes
an error.
So every solution has a different drawback, but what if we can combine
them somehow?! This commit tries exactly that.
We use ps(1) from the host and execute that in the container's pid
namespace.
There are some security concerns that must be addressed:
- mount the executable paths for ps and podman itself readonly to
prevent the container from overwriting it via /proc/self/exe.
- set NO_NEW_PRIVS, SET_DUMPABLE and PDEATHSIG
- close all non std fds to prevent leaking files in that the caller had
open
- unset all environment variables to not leak any into the contianer
Technically this could be a breaking change if somebody does not
have ps on the host and only in the container but I find that very
unlikely, we still have the exec in container fallback.
Because this can be insecure when the contianer has CAP_SYS_PTRACE we
still only use the podman exec version in that case.
This updates the docs accordingly, note that podman pod top never falls
back to executing ps in the container as this makes no sense with
multiple containers so I fixed the docs there as well.
Fixes#19001
Fixes https://bugzilla.redhat.com/show_bug.cgi?id=2215572
Signed-off-by: Paul Holzinger <pholzing@redhat.com>
Note: this makes info.go linux-only since it mixes linux-specific and
generic code. This should be addressed in a separate refactoring PR.
[NO NEW TESTS NEEDED]
Signed-off-by: Doug Rabson <dfr@rabson.org>
The libpod package should only compile on linux. The remote client
should never try to import this package.
Since these files do not add any value we should remove them, this
prevents people from accidentally importing this package because it would
fail to compile on windows/macos.
[NO TESTS NEEDED]
Signed-off-by: Paul Holzinger <pholzing@redhat.com>
We missed bumping the go module, so let's do it now :)
* Automated go code with github.com/sirkon/go-imports-rename
* Manually via `vgrep podman/v2` the rest
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
With the advent of Podman 2.0.0 we crossed the magical barrier of go
modules. While we were able to continue importing all packages inside
of the project, the project could not be vendored anymore from the
outside.
Move the go module to new major version and change all imports to
`github.com/containers/libpod/v2`. The renaming of the imports
was done via `gomove` [1].
[1] https://github.com/KSubedi/gomove
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
the compilation demands of having libpod in main is a burden for the
remote client compilations. to combat this, we should move the use of
libpod structs, vars, constants, and functions into the adapter code
where it will only be compiled by the local client.
this should result in cleaner code organization and smaller binaries. it
should also help if we ever need to compile the remote client on
non-Linux operating systems natively (not cross-compiled).
Signed-off-by: baude <bbaude@redhat.com>
Use github.com/containers/psgo instead of execing `ps (1)`. The psgo
library enables a much more flexible interface with respect to which
data to be printed (e.g., capabilities, seccomp mode, PID, PCPU, etc.)
while the output can be parsed reliably. The library does not use
ps (1) but parses /proc and /dev instead. To list the processes of a
given container, psgo will join the mount namespace of the given
container and extract all data from there.
Notice that this commit breaks compatibility with docker-top.
Signed-off-by: Valentin Rothberg <vrothberg@suse.com>
Closes: #1113
Approved by: rhatdan
Oleksandr Redko
Paul Holzinger
Doug Rabson
Valentin Rothberg
Josh Soref
Daniel J Walsh
Miloslav Trmač
baude
Valentin Rothberg