February 2025 - dev

[PATCH v3 0/3] More graceful handling of migration without passt-repair
by David Gibson 27 Feb '25

27 Feb '25

From Red Hat internal testing we've had some reports that if attempting to migrate without passt-repair, the failure mode is uglier than we'd like. The migration fails, which is somewhat expected, but we don't correctly roll things back on the source, so it breaks network there as well. Handle this more gracefully allowing the migration to proceed in this case, but allow TCP connections to break I've test patches 1..2/3 reasonably: * I get a clean migration if there are now active flows * Migration completes, although connections are broken if passt-repair isn't connected * Basic test suite (minus perf) Patch 3 I've run the basic test suite on, but haven't tested the specific functionality of. Alas, I've spent most of today battling with RHEL, virt-install, unshare and various other things trying to create a test environment simulating two hosts with (possibly) different addresses. Despite the example given by Stefano in reply to the previous version, I haven't really succeeded yet. There are more fragile cases that I'm looking to fix, particularly the die()s in flow_migrate_source_rollback() and elsewhere, however I ran into various complications that I didn't manage to sort out today. I'll continue looking at those tomorrow. David Gibson (3): migrate, flow: Trivially succeed if migrating with no flows migrate, flow: Don't attempt to migrate TCP flows without passt-repair migrate, tcp: Don't attempt to carry on migration after flow_alloc_cancel() flow.c | 17 +++++++++++++++-- tcp.c | 5 ++++- 2 files changed, 19 insertions(+), 3 deletions(-) -- 2.48.1

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[PATCH v6 0/4] Reconstruct ICMP headers for failed UDP connect
by Jon Maloy 26 Feb '25

26 Feb '25

Reconstruct incoming ICMP headers for failed UDP connect and forward back to local peer. v2: - Added patch breaking out udp header creation from function tap_udp4_send(). - Updated the ICMP creation by using the new function. - Added logics to find correct flow, depending on origin. - All done after feedback from David Gibson. v3: - More changes after feedback from David Gibson. v4: - Even more changes after feedback from D. Gibson v5: - Added corresponding patches for IPv6 v6: - Fixed some small nits after comments from D. Gibson. Jon Maloy (4): tap: break out building of udp header from tap_udp4_send function udp: create and send ICMPv4 to local peer when applicable tap: break out building of udp header from tap_udp6_send function udp: create and send ICMPv6 to local peer when applicable tap.c | 86 +++++++++++++++++++++++++---------- tap.h | 15 ++++++ udp.c | 121 ++++++++++++++++++++++++++++++++++++++++++++----- udp_internal.h | 2 +- udp_vu.c | 4 +- 5 files changed, 189 insertions(+), 39 deletions(-) -- 2.48.1

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[PATCH] seccomp.sh: Silence stty errors
by Michal Privoznik 24 Feb '25

24 Feb '25

When printing list of allowed syscalls the width of terminal is obtained for nicer output (see commit below). The width is obtained by running 'stty'. While this works when building from a console, it doesn't work during rpmbuild/emerge/.. as stdout is usually not a console but a logfile and stdin is usually /dev/null or something. This results in stty reporting errors like this: stty: 'standard input': Inappropriate ioctl for device Redirect stty's stderr to /dev/null to silence it. Fixes: 712ca3235329b049bf9a4e481ba38a4c64768e8b Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com> --- I've noticed the error when running emerge on my local system, but then also found it on a recent koji build: https://kojipkgs.fedoraproject.org//packages/passt/0%5E20250217.ga1e48a0/2.… seccomp.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/seccomp.sh b/seccomp.sh index 4c521ae..a7bc417 100755 --- a/seccomp.sh +++ b/seccomp.sh @@ -255,7 +255,7 @@ for __p in ${__profiles}; do __calls="${__calls} ${EXTRA_SYSCALLS:-}" __calls="$(filter ${__calls})" - cols="$(stty -a | sed -n 's/.*columns $[0-9]*$.*/\1/p' || :)" 2>/dev/null + cols="$(stty -a 2>/dev/null | sed -n 's/.*columns $[0-9]*$.*/\1/p' || :)" 2>/dev/null case $cols in [0-9]*) col_args="-w ${cols}";; *) col_args="";; esac echo "seccomp profile ${__p} allows: ${__calls}" | tr '\n' ' ' | fmt -t ${col_args} -- 2.45.3

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[PATCH 0/3] Tweaks to mode handling
by David Gibson 24 Feb '25

24 Feb '25

While working on something else, I got mildly irritated by the fact that there's no a consistent place after which we can rely on the mode. We detect passt vs. pasta early, but only split out vhost-user later, which forces some other things later still. David Gibson (3): conf: Move mode detection into helper function conf: Detect vhost-user mode earlier conf: Use the same optstring for passt and pasta modes conf.c | 87 ++++++++++++++++++++++++++++++++++++++++++--------------- conf.h | 1 + passt.c | 14 ++-------- 3 files changed, 68 insertions(+), 34 deletions(-) -- 2.48.1

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[PATCH v5 0/4] Reconstruct ICMP headers for failed UDP connect
by Jon Maloy 24 Feb '25

24 Feb '25

Reconstruct incoming ICMP headers for failed UDP connect and forward back to local peer. v2: - Added patch breaking out udp header creation from function tap_udp4_send(). - Updated the ICMP creation by using the new function. - Added logics to find correct flow, depending on origin. - All done after feedback from David Gibson. v3: - More changes after feedback from David Gibson. v4: - Even more changes after feedback from D. Gibson v5: - Added corresponding patches for IPv6 Jon Maloy (4): tap: break out building of udp header from tap_udp4_send function udp: create and send ICMPv4 to local peer when applicable tap: break out building of udp header from tap_udp6_send function udp: create and send ICMPv6 to local peer when applicable tap.c | 84 ++++++++++++++++++++++++---------- tap.h | 15 +++++++ udp.c | 119 ++++++++++++++++++++++++++++++++++++++++++++----- udp_internal.h | 2 +- udp_vu.c | 4 +- 5 files changed, 187 insertions(+), 37 deletions(-) -- 2.48.1

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[PATCH 0/2] RFC: More graceful handling of migration without passt-repair (UNTESTED)
by David Gibson 21 Feb '25

21 Feb '25

From Red Hat internal testing we've had some reports that if attempting to migrate without passt-repair, the failure mode is uglier than we'd like. The migration fails, which is somewhat expected, but we don't correctly roll things back on the source, so it breaks network there as well. Handle this more gracefully allowing the migration to proceed in this case, but allow TCP connections to break Unfortunately, I only spotted the ticket about this quite late in my day. I'm posting this now for visibility, but I ran out of time to test it. I'll do that tomorrow if someone doesn't pick it up before then. David Gibson (2): migrate, flow: Trivially succeed if migrating with no flows migrate, flow: Don't attempt to migrate TCP flows without passt-repair flow.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) -- 2.48.1

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[PATCH 0/4] passt-repair improvements
by David Gibson 21 Feb '25

21 Feb '25

This series has a number of minor clean ups to passt-repair, plus one more significant change. The latter allows passt-repair to report partial failures, but does require a small change to its protocol. David Gibson (4): passt-repair: Add die() macro passt-repair: Consistently avoid strerror() passt-repair: Improve validation of anciliary data length passt-repair: Allow passt-repair to report partial failures passt-repair.c | 126 ++++++++++++++++++++++++------------------------- repair.c | 11 +++-- 2 files changed, 68 insertions(+), 69 deletions(-) -- 2.48.1

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[PATCH v3 0/1] Improve validation of --mtu option
by David Gibson 21 Feb '25

21 Feb '25

Here are some of the more straightforward parts of my patches making various MTU related fixes. These ones improve how we validate the --mtu option. Changes since v2: * Don't disable a protocol because the MTU is too small, just warn. It's only an advertised MTU, not an enforced MTU David Gibson (1): conf: Be more precise about minimum MTUs conf.c | 18 +++++++++++++++--- ip.h | 7 +++++++ util.h | 6 ------ 3 files changed, 22 insertions(+), 9 deletions(-) -- 2.48.1

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[PATCH v3 0/2] Reconstruct ICMP headers for failed UDP connect
by Jon Maloy 21 Feb '25

21 Feb '25

Reconstruct incoming ICMP headers for failed UDP connect and forward back to local peer. v2: - Added patch breaking out udp header creation from function tap_udp4_send(). - Updated the ICMP creation by using the new function. - Added logics to find correct flow, depending on origin. - All done after feedback from David Gibson. v3: - More changes after feedback from David Gibson. Jon Maloy (2): tap: break out building of udp header from tap_udp4_send function udp: create and send ICMPv4 to local peer when applicable tap.c | 36 ++++++++++++++----- tap.h | 7 ++++ udp.c | 96 +++++++++++++++++++++++++++++++++++++++++++------- udp_internal.h | 3 +- udp_vu.c | 4 +-- 5 files changed, 121 insertions(+), 25 deletions(-) -- 2.48.1

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[PATCH] contrib/selinux: Enable mapping guest memory for libvirt guests
by Stefano Brivio 20 Feb '25

20 Feb '25

This doesn't actually belong to passt's own policy: we should export an interface and libvirt's policy should use it, because passt's policy shouldn't be aware of svirt_image_t at all. However, libvirt doesn't maintain its own policy, which makes policy updates rather involved. Add this workaround to ensure --vhost-user is working in combination with libvirt, as it might take ages before we can get the proper rule in libvirt's policy. Reported-by: Laine Stump <laine(a)redhat.com> Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com> --- contrib/selinux/passt.te | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/contrib/selinux/passt.te b/contrib/selinux/passt.te index 8e6120e..f595079 100644 --- a/contrib/selinux/passt.te +++ b/contrib/selinux/passt.te @@ -24,6 +24,12 @@ require { type tmpfs_t; type root_t; + # Workaround: passt --vhost-user needs to map guest memory, but + # libvirt doesn't maintain its own policy, which makes updates + # particularly complicated. To avoid breakage in the short term, + # deal with it in passt's own policy. + type svirt_image_t; + class file { ioctl getattr setattr create read write unlink open relabelto execute execute_no_trans map }; class dir { search write add_name remove_name mounton }; class chr_file { append read write open getattr ioctl }; @@ -131,3 +137,9 @@ allow passt_t user_tmp_t:dir { add_name write }; allow passt_t user_tmp_t:file { create open }; allow passt_t user_tmp_t:sock_file { create read write unlink }; allow passt_t unconfined_t:unix_stream_socket { read write }; + +# Workaround: passt --vhost-user needs to map guest memory, but +# libvirt doesn't maintain its own policy, which makes updates +# particularly complicated. To avoid breakage in the short term, +# deal with it in passt's own policy. +allow passt_t svirt_image_t:file { read write map }; -- 2.43.0

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