繞過 Screensaver Lock 的有趣話題...

Hacker News Daily 上看到「Screensaver lock by-pass via the virtual keyboard」這篇,裡面這邊題到了 screensaver lock 的有趣話題。

先講嚴肅一點的,這個 bug 被編號為 CVE-2020-25712,問題出在 xorg-x11-server 上:

A flaw was found in xorg-x11-server before 1.20.10. A heap-buffer overflow in XkbSetDeviceInfo may lead to a privilege escalation vulnerability. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

比較有趣的事情是,這個 bug 是小朋友在亂玩時拉出 virtual keyboard 觸發的:

A few weeks ago, my kids wanted to hack my linux desktop, so they typed and clicked everywhere, while I was standing behind them looking at them play... when the screensaver core dumped and they actually hacked their way in! wow, those little hackers...


I tried to recreate the crash on my own with no success, maybe because it required more than 4 little hands typing and using the mouse on the virtual keyboard.

另外一個人也說他家小朋友也弄出 segfault 了:

My kids came upon a similar cinnamon-screensaver segfault! I've emailed details of how to reproduce the problem to root@linuxmint.com.

小朋友超強 XDDD


上個禮拜丟出來很轟動的一篇「side project」,三個月不斷的打穿蘋果的企業網路:「We Hacked Apple for 3 Months: Here’s What We Found」,對應的 Hacker News 討論可以在「We Hacked Apple for 3 Months (samcurry.net)」這邊看到。


This was originally meant to be a side project that we'd work on every once in a while, but with all of the extra free time with the pandemic we each ended up putting a few hundred hours into it.

這是五個人通力合作打了三個月出來的成果,依照他們的回報數字,共打出了 55 個「洞」,考慮到週休的情況,幾乎是天天打洞出來玩:

There were a total of 55 vulnerabilities discovered with 11 critical severity, 29 high severity, 13 medium severity, and 2 low severity reports. These severities were assessed by us for summarization purposes and are dependent on a mix of CVSS and our understanding of the business related impact.

文章裡沒有對每個安裝漏洞都描述,但有針對一些比較「有趣」的漏洞說明,雖然看了以後知道是怎麼一回事,但對這些手法沒這麼熟,你叫我打我還是不會打啊 XDDD 反而是當作表演藝術來看...

五家公司提出 Form S-1:Asana、Unity、Snowflake、sumo logic、JFrog

Hacker News 上看到五家公司都準備要上市而丟出 Form S-1 的情況頗熱鬧的,申請文件可以在「ASANA, INC. (d855753ds1.htm)」、「UNITY SOFTWARE INC. (d908875ds1.htm)」、「Snowflake Inc. (snowflakes-1.htm)」、「Sumo Logic, Inc. (d821436ds1.htm)」與「JFrog Ltd. (d841831ds1.htm)」這邊翻到。

當然很多人都有類似的疑問,就是為什麼大家突然都急著要 IPO,在「Ask HN: There are 5 S-1 posts on the front page, what explains the rush?」這邊有些討論,而且也提到了一些有趣的現象,像是這五家公司到目前都是虧錢的,不過這已經是這幾年的常態了,倒是沒什麼需要大驚小怪的:

Asana lost 120m last year
Snowflake lost 350m last year
Unity lost 160m last year
Sumo Logic lost 43m last year
Jfrog lost 400k last year

Out of curiosity, is it normal for companies to IPO this far away from profitability, or is this a recent tech thing? I feel like it was a big deal when uber IPO'd so far away from profitability, now it seems standard.


在 Unix 環境裡各種奇怪名稱的原因說明

Hacker News Daily 上看到的,DebianWiki 上有一頁整理了很多「比較特別的」軟體或是指令的名稱由來:「WhyTheName」。

像是 Git

(distributed VCS) semi-arbitrary short word


透過 /etc/hosts 擋廣告與追蹤的軟體

Hacker News Daily 上看到 Maza ad blocking,這是一個擋廣告與追蹤的軟體,原理就是在 DNS 上檔掉某些網域。

運作方式跟 Pi-hole 接近,其中 Pi-hole 是提供一個 DNS server 擋,這套軟體則是透過 /etc/hosts 來擋。

目前只支援 macOSLinux,不過這樣看起來使用的族群有點怪,因為在 desktop 上有更多手段可以擋,透過 DNS 類的擋法主要還是拿來對手機上無法無天的 app...



Hacker News Daily 上看到的數學邏輯問題:「“Which answer in this list is the correct answer to this question?”」。


Which answer in this list is the correct answer to this question?

  • All of the below.
  • None of the below.
  • All of the above.
  • One of the above.
  • None of the above.
  • None of the above.

accepted 的那個是推演的答案,但最高分的那個是寫程式窮舉 XDDD (不得不說大家都很愛這味...)

把 PostgreSQL 的 EXPLAIN 轉成 Flamegraph

Hacker News Daily 上看到 mgartner/pg_flame 這個專案,可以把 PostgreSQLEXPLAIN 結果 (JSON 格式) 轉成 Flamegraph (用 HTML 呈現):

不過我是直接看 EXPLAIN 的輸出比較習慣... 但如果需要做投影片的時候,應該是個好工具?

Startpage 被廣告公司收購

Hacker News 上看到 Reddit 上的消息 (看起來有陣子了):「Startpage is now owned by an advertising company」。

Startpage 算是之前有在用的 default search engine,但發現有很多 bug 後就不太用了。目前還是先設 DuckDuckGo,然後在需要的時候用之前寫的 press-g-to-google-duckduckgo 切到 Google 去找...

DuckDuckGo 還是有搜尋品質的問題...

Hacker News

早上看到「Tell HN: Thank you for not redesigning Hacker News」這篇,作者在網路速度受限的地區,上各種網站幾乎都不會動,但 Hacker News 沒有改用一堆前端框架,而是保留使用 HTML 反而讓頁面維持極小:

I’m currently in a country with low speed internet and the entire ‘modern’ web is basically unusable except HN, which still loads instantly. Reddit, Twitter, news and banking sites are all painfully slow or simply time out altogether.

To PG, the mods and whoever else is responsible: thank you for not trying to ‘fix’ what isn’t broken.

順手開了一下網路工具來看,發現單一元件最大的居然是 favicon XDDD:

Wikipedia 上列出來的相容性,如果只支援 IE11+ 的話,看起來可以改用 PNG,大小就已經有明顯的改善了:

-rw-r--r-- 1 gslin staff 7527 Sep  2 09:50 favicon.ico
-rw-r--r-- 1 gslin staff 2598 Sep  2 09:51 favicon.png

PostgreSQL 的 Don't Do This

Hacker News Daily 上看到的資料,整理了 PostgreSQL 上不要使用的功能:「Don't Do This」,而且是放在官方網域 wiki.postgresql.org 上。

裡面這些想法不知道出處是哪邊... 有不少功能算是 PostgreSQL 特有的功能 (以 open source RDBMS 這個領域來看),而且大概也還想的到用的場景,你卻在上面叫大家不要用,再寫的時候大概是吸了一批很純的,已經不知道要從哪邊開始吐槽...

要看的話連同 Hacker News 上的留言一起看會比較有前因後果:「https://news.ycombinator.com/item?id=19817531」。