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			85 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			Bash
		
	
	
	
	
	
			
		
		
	
	
			85 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			Bash
		
	
	
	
	
	
#!/usr/bin/env bash
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# Tell build process to exit if there are any errors.
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set -oue pipefail
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# Reference: https://gist.github.com/ok-ryoko/1ff42a805d496cb1ca22e5cdf6ddefb0#usrbinchage
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whitelist=(
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    # Needed for flatpak on no-userns images
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    "/usr/bin/bwrap"
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    # Requires cap_setuid if the suid bit is removed
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    "/usr/bin/gpasswd"
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    # "In effect, when the SUID bit is unset on /usr/bin/mount, mount(8) will never drop permissions. If /usr/bin/mount were to have a"
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    # "nonempty permitted capability set and its effective capability bit were set, then mount(8) would never have its effective " 
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    # "capability set cleared during execution, potentially allowing unprivileged users to perform actions they shouldn’t be able to perform"
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    # https://gist.github.com/ok-ryoko/1ff42a805d496cb1ca22e5cdf6ddefb0#can-we-replace-the-suid-bit-with-zero-or-more-file-capabilities-4
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    "/usr/bin/mount"
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    # Required for nvidia images
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    "/usr/bin/nvidia-modprobe"
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    # https://gist.github.com/ok-ryoko/1ff42a805d496cb1ca22e5cdf6ddefb0#can-we-replace-the-suid-bit-with-zero-or-more-file-capabilities
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    "/usr/bin/passwd"
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    # https://gist.github.com/ok-ryoko/1ff42a805d496cb1ca22e5cdf6ddefb0#why-does-this-binary-need-to-be-suid-root-9
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    "/usr/bin/pkexec"
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    # https://gist.github.com/ok-ryoko/1ff42a805d496cb1ca22e5cdf6ddefb0#can-we-replace-the-suid-bit-with-zero-or-more-file-capabilities-6
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    "/usr/bin/su"
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    # https://gist.github.com/ok-ryoko/1ff42a805d496cb1ca22e5cdf6ddefb0#can-we-replace-the-suid-bit-with-zero-or-more-file-capabilities-6
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    "/usr/bin/sudo"
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    # See /usr/bin/mount
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    "/usr/bin/umount"
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    # https://gitlab.freedesktop.org/polkit/polkit/-/issues/168
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    "/usr/lib/polkit-1/polkit-agent-helper-1"
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    # https://github.com/secureblue/secureblue/issues/119
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    "/usr/lib64/libhardened_malloc-light.so"
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    "/usr/lib64/libhardened_malloc-pkey.so"
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    "/usr/lib64/libhardened_malloc.so"
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    # Required for chrome suid sandbox on no-userns images
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    "/usr/lib64/chromium-browser/chrome-sandbox"
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    # https://github.com/secureblue/secureblue/issues/119
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    "/usr/lib64/glibc-hwcaps/x86-64/libhardened_malloc-light.so"
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    "/usr/lib64/glibc-hwcaps/x86-64/libhardened_malloc-pkey.so"
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    "/usr/lib64/glibc-hwcaps/x86-64/libhardened_malloc.so"
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    "/usr/lib64/glibc-hwcaps/x86-64-v2/libhardened_malloc-light.so"
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    "/usr/lib64/glibc-hwcaps/x86-64-v2/libhardened_malloc-pkey.so"
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    "/usr/lib64/glibc-hwcaps/x86-64-v2/libhardened_malloc.so"
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    "/usr/lib64/glibc-hwcaps/x86-64-v3/libhardened_malloc-light.so"
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    "/usr/lib64/glibc-hwcaps/x86-64-v3/libhardened_malloc-pkey.so"
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    "/usr/lib64/glibc-hwcaps/x86-64-v3/libhardened_malloc.so"
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    "/usr/lib64/glibc-hwcaps/x86-64-v4/libhardened_malloc-light.so"
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    "/usr/lib64/glibc-hwcaps/x86-64-v4/libhardened_malloc-pkey.so"
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    "/usr/lib64/glibc-hwcaps/x86-64-v4/libhardened_malloc.so"
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    # Requires cap_setgid,cap_setuid if the SUID bit is removed
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    "/usr/sbin/grub2-set-bootflag"
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)
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is_in_whitelist() {
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    local binary="$1"
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    for allowed_binary in "${whitelist[@]}"; do
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        if [ "$binary" = "$allowed_binary" ]; then
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            return 0
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        fi
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    done
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    return 1
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}
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find /usr -type f -perm /4000 |
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    while IFS= read -r binary; do
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        if ! is_in_whitelist "$binary"; then
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            echo "Removing SUID bit from $binary"
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            chmod u-s "$binary"
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            echo "Removed SUID bit from $binary"
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        fi
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    done
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find /usr -type f -perm /2000 |
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    while IFS= read -r binary; do
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        if ! is_in_whitelist "$binary"; then
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            echo "Removing SGID bit from $binary"
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            chmod g-s "$binary"
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            echo "Removed SGID bit from $binary"
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        fi
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    done
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systemctl enable setcapsforunsuidbinaries.service
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