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Why PATH=/dev/null vs export PATH="" |
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On Thu, Sep 7, 2017 at 3:36 AM, Michał Górny <mgorny@g.o> wrote: |
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> Dnia 31 sierpnia 2017 22:45:42 CEST, "Michał Górny" <mgorny@g.o> |
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> napisał(a): |
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> >Set PATH to /dev/null when sourcing the ebuild for dependency |
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> >resolution |
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> >in order to prevent shell from finding external commands via PATH |
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> >lookup. While this does not prevent executing programs via full path, |
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> >it |
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> >should catch the majority of accidental uses. |
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> > |
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> >Closes: https://github.com/gentoo/portage/pull/199 |
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> > |
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> >// Note: this can't be merged right now since we still have ebuilds |
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> >// calling external commands; see: |
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> >// https://bugs.gentoo.org/show_bug.cgi?id=629222 |
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> |
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> Update: gentoo is green now |
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> |
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> >--- |
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> > bin/ebuild.sh | 6 +++++- |
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> > bin/isolated-functions.sh | 4 ++++ |
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> > 2 files changed, 9 insertions(+), 1 deletion(-) |
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> > |
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> >diff --git a/bin/ebuild.sh b/bin/ebuild.sh |
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> >index c23561651..94a44d534 100755 |
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> >--- a/bin/ebuild.sh |
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> >+++ b/bin/ebuild.sh |
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> >@@ -80,8 +80,12 @@ else |
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> > done |
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> > unset funcs x |
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> > |
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> >+ # prevent the shell from finding external executables |
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> >+ # note: we can't use empty because it implies current directory |
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> >+ _PORTAGE_ORIG_PATH=${PATH} |
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> >+ export PATH=/dev/null |
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> > command_not_found_handle() { |
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> >- die "Command not found while sourcing ebuild: ${*}" |
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> >+ die "External commands disallowed while sourcing ebuild: |
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> ${*}" |
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> > } |
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> > fi |
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> > |
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> >diff --git a/bin/isolated-functions.sh b/bin/isolated-functions.sh |
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> >index e320f7132..b28e44f18 100644 |
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> >--- a/bin/isolated-functions.sh |
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> >+++ b/bin/isolated-functions.sh |
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> >@@ -121,6 +121,10 @@ __helpers_die() { |
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> > } |
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> > |
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> > die() { |
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> >+ # restore PATH since die calls basename & sed |
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> >+ # TODO: make it pure bash |
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> >+ [[ -n ${_PORTAGE_ORIG_PATH} ]] && PATH=${_PORTAGE_ORIG_PATH} |
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> >+ |
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> > set +x # tracing only produces useless noise here |
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> > local IFS=$' \t\n' |
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> > |
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> |
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> |
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> -- |
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> Best regards, |
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> Michał Górny (by phone) |
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> |
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> |