Re: [PATCH 1/2] exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case
On Wed, Oct 30, 2024 at 02:37:31PM -0600, Tycho Andersen wrote: > From: Tycho Andersen > > Zbigniew mentioned at Linux Plumber's that systemd is interested in > switching to execveat() for service execution, but can't, because the > contents of /proc/pid/comm are the file descriptor which was used, > instead of the path to the binary. This makes the output of tools like > top and ps useless, especially in a world where most fds are opened > CLOEXEC so the number is truly meaningless. > > Change exec path to fix up /proc/pid/comm in the case where we have > allocated one of these synthetic paths in bprm_init(). This way the actual > exec machinery is unchanged, but cosmetically the comm looks reasonable to > admins investigating things. > > Signed-off-by: Tycho Andersen > Suggested-by: Zbigniew Jędrzejewski-Szmek > CC: Aleksa Sarai > Link: https://github.com/uapi-group/kernel-features#set-comm-field-before-exec > --- We finally went full circle back to what was originally proposed :) Reviewed-by: Christian Brauner
Re: [PATCH 1/2] exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case
On Sat, Nov 02, 2024 at 11:29:55AM +, Zbigniew Jędrzejewski-Szmek wrote: > On Thu, Oct 31, 2024 at 03:10:37PM -0700, Kees Cook wrote: > > On Wed, 30 Oct 2024 14:37:31 -0600, Tycho Andersen wrote: > > > Zbigniew mentioned at Linux Plumber's that systemd is interested in > > > switching to execveat() for service execution, but can't, because the > > > contents of /proc/pid/comm are the file descriptor which was used, > > > instead of the path to the binary. This makes the output of tools like > > > top and ps useless, especially in a world where most fds are opened > > > CLOEXEC so the number is truly meaningless. > > > > > > [...] > > > > Applied to for-next/execve, thanks! > > > > [1/2] exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case > > https://git.kernel.org/kees/c/7bdc6fc85c9a > > [2/2] selftests/exec: add a test for execveat()'s comm > > https://git.kernel.org/kees/c/bd104872311a > > I tested this with systemd compiled with -Dfexece=true and it all > seems to work fine. Thanks! Great; thank you! -- Kees Cook
Re: [PATCH 1/2] exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case
On Thu, Oct 31, 2024 at 03:10:37PM -0700, Kees Cook wrote: > On Wed, 30 Oct 2024 14:37:31 -0600, Tycho Andersen wrote: > > Zbigniew mentioned at Linux Plumber's that systemd is interested in > > switching to execveat() for service execution, but can't, because the > > contents of /proc/pid/comm are the file descriptor which was used, > > instead of the path to the binary. This makes the output of tools like > > top and ps useless, especially in a world where most fds are opened > > CLOEXEC so the number is truly meaningless. > > > > [...] > > Applied to for-next/execve, thanks! > > [1/2] exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case > https://git.kernel.org/kees/c/7bdc6fc85c9a > [2/2] selftests/exec: add a test for execveat()'s comm > https://git.kernel.org/kees/c/bd104872311a I tested this with systemd compiled with -Dfexece=true and it all seems to work fine. Thanks! Zbyszek
Re: [PATCH 1/2] exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case
On Wed, 30 Oct 2024 14:37:31 -0600, Tycho Andersen wrote: > Zbigniew mentioned at Linux Plumber's that systemd is interested in > switching to execveat() for service execution, but can't, because the > contents of /proc/pid/comm are the file descriptor which was used, > instead of the path to the binary. This makes the output of tools like > top and ps useless, especially in a world where most fds are opened > CLOEXEC so the number is truly meaningless. > > [...] Applied to for-next/execve, thanks! [1/2] exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case https://git.kernel.org/kees/c/7bdc6fc85c9a [2/2] selftests/exec: add a test for execveat()'s comm https://git.kernel.org/kees/c/bd104872311a Take care, -- Kees Cook
