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diff --git a/served/things/memoryleak/memoryleak.html b/served/things/memoryleak/memoryleak.html new file mode 100644 index 0000000..bacbe5e --- /dev/null +++ b/served/things/memoryleak/memoryleak.html @@ -0,0 +1,117 @@ +--- +template=post +title=Memoryleak was +style=/styles/post.css +style=memoryleak.css +--- + +A virtual machine slowly decaying. Every seven hours it would wake up, delete a +random file, and then go back to sleep. It posted about it at +<a href="https://amble.quest/memoryleak">amble.quest/memoryleak</a> + +<img src="images/screenshot.png" alt="a screenshot of memoryleak's profile on amble.quest" + style="width: 100%; border: 1px solid var(--text);"> + +[@paragraphs off] +<section style="margin: 1rem 0;"> + <img src="images/ddr2_closest.png" + style="width: 10rem; aspect-ratio: 1 / 1; float: left; margin: 0 1rem 0.5rem 0; border: 1px solid var(--text);" + alt="a DDR2 module broken in half at it's notch. you can see the fibre of the PCB. on the side facing the camera there is a memory chip split in half and peaking open." /> + + <p style="margin: 0"> + It's face is a RAM module that I broke in half. I processed the raw photo + through my perpetually-in-process image processing project. + I am very happy with how it came out! The split-and-<i>just</i>-peaking-open + memory chip is my favourite bit of it.</p> +</section> + +<p style="clear: both; margin-top: 1rem">The virtual machine was an <a href="https://www.alpinelinux.org">Alpine + Linux</a> + virtual image with curl installed. It was configured to run a script called + <code>pull</code> on boot through the <code>pull_service</code> OpenRC script +</p> + +<div id="float-hell"> + <section id="downloads"> + <h2 style="text-decoration: underline;">downloads</h2> + <h3>logs</h3> + <ul> + <li><a href="files/did">did</a></li> + <li><a href="files/persistent">persistent</a></li> + </ul> + <h3>scripts</h3> + <ul> + <li><a href="files/memoryleak.sh">memoryleak.sh</a></li> + <li><a href="files/memoryleak.service">memoryleak.service</a></li> + <li><a href="files/pull">pull</a></li> + <li><a href="files/pull_service">pull_service</a></li> + </ul> + <h3>images</h3> + <ul> + <li><a href="images/ddr2_closest.png">ddr2_closest.png</a></li> + <li><a href="images/ddr2.png">ddr2.png</a> (32MB)</li> + </ul> + </section> + + <p> + <code>pull</code> would get a list of every file on the system and pick one at + random to delete. It'd then post that message to amble.quest through a relay I + made <i>(but was realistically not needed)</i> and actually delete that file. Then + it would turn itself off. + </p> + + <p> + memoryleak was started from an Arch Linux host with a systemd service, <code>memoryleak.service</code> that + launched qemu <i>(through <code>memoryleak.sh</code>)</i> + </p> + + <p> + It was really nice watching it run! The 7 hour spacing worked a treat. It was often + enough that I wasn't annoyed at it's slowness and it wasn't a factor of 24 which had + it drifting around the day. + </p> + <p> + Every file on the system had an even shot at getting deleted, even the ephemeral ones! The + rare occasion it hit a persist file was very exciting. In the end it was the <code>musl</code> + at the heart of it that finally gave up. + </p> + <p> + A total of 625 files were deleted. 354 of them were from /sys, 240 were from /proc, and + 31 were persistent files. I've filtered the logs <i>(from the <code>did</code> file)</i> + and picked out the persistent paths. They're in <code>persistent</code> as well as + in the little box below. + </p> + <pre style="width: 100%; max-height: 10rem; overflow: scroll; font-size: 0.75rem"> + 23: /lib/modules/5.15.94-0-virt/kernel/net/netfilter/xt_connlabel.ko.gz + 25: /lib/modules/5.15.94-0-virt/kernel/net/netfilter/ipset/ip_set_bitmap_ip.ko.gz + 30: /usr/share/ca-certificates/mozilla/emSign_Root_CA_-_C1.crt + 46: /lib/modules/5.15.94-0-virt/kernel/drivers/net/mdio/fwnode_mdio.ko.gz + 56: /lib/modules/5.15.94-0-virt/kernel/drivers/video/fbdev/core/fb.ko.gz + 63: /lib/dasd-functions.sh +116: /usr/share/syslinux/cpuid.c32 +137: /usr/share/syslinux/lpxelinux.0 +139: /usr/share/ca-certificates/mozilla/TWCA_Root_Certification_Authority.crt +161: /lib/apk/db/installed +198: /usr/share/syslinux/isolinux.bin +208: /lib/modules/5.15.94-0-virt/kernel/crypto/cryptd.ko.gz +237: /lib/modules/5.15.94-0-virt/kernel/net/netfilter/ipvs/ip_vs_lblcr.ko.gz +276: /lib/modules/5.15.94-0-virt/kernel/net/netfilter/nft_quota.ko.gz +298: /lib/modules/5.15.94-0-virt/kernel/fs/ksmbd/ksmbd.ko.gz +299: /lib/modules/5.15.94-0-virt/kernel/net/netfilter/xt_physdev.ko.gz +310: /usr/share/syslinux/syslinux.com +313: /lib/rc/bin/checkpath +327: /etc/secfixes.d/alpine +401: /lib/modules/5.15.94-0-virt/kernel/fs/nls/nls_cp869.ko.gz +411: /etc/mkinitfs/features.d/ocfs2.modules +443: /lib/modules/5.15.94-0-virt/kernel/net/netfilter/nf_conncount.ko.gz +452: /usr/share/ca-certificates/mozilla/TrustCor_ECA-1.crt +491: /sbin/rc-service +541: /lib/modules/5.15.94-0-virt/kernel/net/vmw_vsock/vmw_vsock_virtio_transport.ko.gz +561: /lib/modules/5.15.94-0-virt/kernel/net/netfilter/xt_osf.ko.gz +580: /lib/rc/bin/service_starting +589: /lib/modules/5.15.94-0-virt/kernel/net/netfilter/xt_policy.ko.gz +599: /usr/share/ca-certificates/mozilla/DigiCert_Trusted_Root_G4.crt +616: /lib/modules/5.15.94-0-virt/kernel/crypto/algif_hash.ko.gz +625: /lib/ld-musl-x86_64.so.1 + </pre> +</div> \ No newline at end of file |