374
Avoid this very common mistake (lemmy.world)
submitted 2 months ago by to c/linuxmemes@lemmy.world
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TranscriptImage of a man pointing a gun at his own foot.

Caption: Installing an AUR package without reading it's PKGBUILD.

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[–] 33 points 2 months ago (7 children)

I usually do, but I don't really know what I should be looking for. What are some red flags?

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  • [–] 42 points 2 months ago* (last edited 2 months ago) (1 child)

    This video taught me a lot.

    Check the list of dependencies. If you really want to vet the package, look through all of the dependencies listed and read their package descriptions on their source page (github, gitlab, codeberg, whathaveyou). Check also the URL, from which makepkg (or yay or whatever) is going to pull some of the data. Is the URL legit?

    PKGBUILD of localsend

    # Maintainer: NourEddineX  
# Contributor: Nixuge  
# Contributor: Noah Vogt <noah@noahvogt.com>  
# Contributor: SpieringsAE (aarch64 addition)  

# Note: 
# using the .deb instead of the .tar.gz as it already contains the icons as well as the .desktop file.  

pkgname=localsend-bin  
pkgver=1.18.0  
pkgrel=1  
pkgdesc='An open source cross-platform alternative to AirDrop'  

LOOK HERE  
url=https://github.com/localsend/LOCALSEND  
LOOK HERE  

arch=('x86_64' 'aarch64')  
license=(Apache-2.0)  

LOOK HERE  
depends=(fuse2 xdg-user-dirs libayatana-appindicator)  
LOOK HERE  

conflicts=('localsend')  
provides=('localsend')  
options=(!debug)  
source_x86_64=("${url}/releases/download/v${pkgver}/LocalSend-${pkgver}-linux-x86-64.deb")  
source_aarch64=("${url}/releases/download/v${pkgver}/LocalSend-${pkgver}-linux-arm-64.deb")  
sha256sums_x86_64=('dae68192ad43a59a68df06454eb5fa4e9a9f86a343fe430165efd8b18863d0f4')  
sha256sums_aarch64=('eb24e724fbdf830c8fb07dfc66b76b8a649923d083278305a63d5d539db4b606')  
_pkgdesktop="localsend_app.desktop"  


prepare() {  
	tar -xf data.tar.zst  
}  

build() {  
	sed -i -E \  
		"s|Exec=localsend_app|Exec=localsend|" \  
		"${srcdir}/usr/share/applications/${_pkgdesktop}"  

	# Adjust .desktop to have it point to the correct icon  
	sed -i -E 's/^Icon=.+/Icon=localsend/' "${srcdir}/usr/share/applications/${_pkgdesktop}"  
}  

package() {  
	# Desktop  
	install -Dm644 "${srcdir}/usr/share/applications/${_pkgdesktop}" "${pkgdir}/usr/share/applications/${pkgname%-*}.desktop" 
	

	# Icons  
	install -dm644 "${pkgdir}/usr/share/icons/"  
	cp -a "${srcdir}/usr/share/icons" "${pkgdir}/usr/share"  
	# Dirty - rename icons to localsend  
	for res in "128x128" "256x256"; do  
		mv "${pkgdir}/usr/share/icons/hicolor/${res}/apps/localsend_app.png" "${pkgdir}/usr/share/icons/hicolor/${res}/apps/localsend.png"  
	done  


	# Executable  
	install -dm755 "${pkgdir}/opt/${pkgname%-*}/"  
	cp -a "${srcdir}/opt/localsend_app/." "${pkgdir}/opt/${pkgname%-*}"  
	# Same as icons - rename to localsend  
	mv "${pkgdir}/opt/${pkgname%-*}/localsend_app" "${pkgdir}/opt/${pkgname%-*}/localsend"  

	# Symlink executable  
	install -dm755 "${pkgdir}/usr/bin"  
	ln -s \  
		"/opt/${pkgname%-*}/${pkgname%-*}" \  
		"${pkgdir}/usr/bin/${pkgname%-*}"  
}

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  • [–] 3 points 2 months ago* (last edited 2 months ago)

    Yeah. There's also some others behaviours to look at.

    Like, does the PKGBUILD install the package on some non-standard location? That's a suspicious behaviour, although it's not an automatic red flag by itself.

    Does it execute arbitrary code or any external script (worse if it's Python, Lua or JS)? That's a HUGE red flag in most of cases.

    Does it (ab)uses of AWK, sed and the like? That's also suspicious in a variety of cases.

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  • [–] 25 points 2 months ago*

    as the other commenter said, but worth echoing:

    • is it suddenly using npm to install/run something? (iirc this was the attack vector for most packages that were infected)
    • suddenly added some weird extra wget/curl/whatever to packaging methods to fetch something weird?
    • are the package's sources (eg. github urls) legit?

    Generally you should be aware of who'se software you're installing -> check if it's downloading the stuff from right place, and nothing extra. The PKGBUILD changes in the aur website are pretty good indicator if something has changed and how.

    edit: npm itself, or it's usage isn't bad - but it is quite suspicious if the AUR package isn't for some webapp or so.

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  • [–] -4 points 2 months ago (2 children)

    Get AI to read it, it'll be 90% good enough

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