git-remote-gcrypt/git-remote-gcrypt
2012-12-16 09:01:02 +00:00

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#!/bin/sh
# git-remote-gcrypt
# Copyright 2013 by Ulrik
# License: GPLv2 or any later version, see http://www.gnu.org/licenses/
#
# See README
#set -x
set -e
Did_find_repo= # yes for connected, no for no repo
Localdir="${GIT_DIR:=.git}/remote-gcrypt"
export GITCEPTION="${GITCEPTION:-}+" # Reuse $Gref except when stacked
Gref="refs/gcrypt/gitception$GITCEPTION"
Gref_rbranch="refs/heads/master"
Repoid=
Packkey_bytes=33 # 33 random bytes for passphrase, still compatible if changed
Hashtype=SHA256 # SHA512 SHA384 SHA256 SHA224 supported.
Packpat="pack :*:"
Manifestfile=91bd0c092128cf2e60e1a608c31e92caf1f9c1595f83f2890ef17c0e4881aa0a
Branchlist=
Packlist=
Keeplist=
Extension_list=
Repack_limit=25
Packlist_delete=
Recipients=
Signers=
Goodsig=
# compat/utility functions
xecho()
{
cat <<EOF
$@
EOF
}
xecho_n() { xecho "$@" | tr -d \\n ; } # kill newlines
echo_git() { xecho "$@" ; } # Code clarity
echo_info() { xecho "gcrypt:" "$@" >&2; }
echo_die() { echo_info "$@" ; exit 1; }
isnull() { case "$1" in "") return 0;; *) return 1;; esac; }
isnonnull() { ! isnull "$1"; }
iseq() { case "$1" in "$2") return 0;; *) return 1;; esac; }
isnoteq() { ! iseq "$@"; }
# Append $2 to $1 with a newline separator
append() { isnull "$1" || xecho "$1" && xecho "$2"; }
isurl() { isnull "${2%%$1://*}"; }
islocalrepo() { isnull "${1##/*}" && [ ! -e "$1/HEAD" ]; }
xgrep() { command grep "$@" || : ; }
sort_C() { LC_ALL=C command sort "$@"; }
sort_stable_k2()
{
awk '{ printf("%08d\t%s\n", NR, $0) }' | sort_C -k 3,3 -k 1,1 |cut -f 2-
}
tac() { sed '1!G;h;$!d'; }
# Split $1 into $prefix_:$suffix_
splitcolon()
{
prefix_=${1%%:*}
suffix_=${1#*:}
}
repoidstr() { xecho "repo $Repoid"; }
## gitception part
# Fetch giturl $1, file $2
gitception_get()
{
# Take care to preserve FETCH_HEAD
local ret_=: obj_id= f_head="$GIT_DIR/FETCH_HEAD"
[ -e "$f_head" ] && command mv -f "$f_head" "$f_head.$$~" || :
git fetch -q -f "$1" "$Gref_rbranch:$Gref" 2>/dev/tty >/dev/null &&
obj_id="$(git ls-tree "$Gref" | xgrep -E '\b'"$2"'$' | awk '{print $3}')" &&
isnonnull "$obj_id" && git cat-file blob "$obj_id" && ret_=: ||
{ ret_=false && : ; }
[ -e "$f_head.$$~" ] && command mv -f "$f_head.$$~" "$f_head" || :
$ret_
}
anon_commit()
{
GIT_AUTHOR_NAME="root" GIT_AUTHOR_EMAIL="root@localhost" \
GIT_AUTHOR_DATE="1356994801 -0400" GIT_COMMITTER_NAME="root" \
GIT_COMMITTER_EMAIL="root@localhost" \
GIT_COMMITTER_DATE="1356994801 -0400" \
git commit-tree "$@" <<EOF
Initial commit
EOF
}
# Get 'tree' from $1, change file $2 to obj id $3
update_tree()
{
local tab_=" "
# $2 is a filename from the repo format
(git ls-tree "$1" | xgrep -v -E '\b'"$2"'$';
xecho "100644 blob $3$tab_$2") | git mktree
}
# Put giturl $1, file $2
# depends on previous GET to set $Gref and depends on PUT_FINAL later
gitception_put()
{
local obj_id= tree_id= commit_id=
obj_id=$(git hash-object -w --stdin) &&
tree_id=$(update_tree "$Gref" "$2" "$obj_id") &&
commit_id=$(anon_commit "$tree_id") &&
git update-ref "$Gref" "$commit_id"
}
# Remove giturl $1, file $2
# depends on previous GET like put
gitception_remove()
{
local tree_id= commit_id= tab_=" "
# $2 is a filename from the repo format
tree_id=$(git ls-tree "$Gref" | xgrep -v -E '\b'"$2"'$' | git mktree) &&
commit_id=$(anon_commit "$tree_id") &&
git update-ref "$Gref" "$commit_id"
}
gitception_new_repo()
{
local empty_tree=4b825dc642cb6eb9a060e54bf8d69288fbee4904
# get any file to update Gref, and if it's not updated we create empty
git update-ref -d "$Gref" || :
gitception_get "$1" "x" || :
git rev-parse -q --verify "$Gref" >/dev/null && return 0 ||
commit_id=$(anon_commit "$empty_tree") &&
git update-ref "$Gref" "$commit_id"
}
## end gitception
# Fetch repo $1, file $2, tmpfile in $3
GET()
{
if isurl sftp "$1"
then
(exec 0>&-; curl -s -S -k "$1/$2") > "$3"
elif isurl rsync "$1"
then
(exec 0>&-; rsync -I -W "${1#rsync://}"/"$2" "$3" >&2)
elif islocalrepo "$1"
then
cat "$1/$2" > "$3"
else
gitception_get "${1#gitception://}" "$2" > "$3"
fi
}
# Put repo $1, file $2 or fail, tmpfile in $3
PUT()
{
if isurl sftp "$1"
then
curl -s -S -k --ftp-create-dirs -T "$3" "$1/$2"
elif isurl rsync "$1"
then
rsync -I -W "$3" "${1#rsync://}"/"$2" >&2
elif islocalrepo "$1"
then
cat > "$1/$2" < "$3"
else
gitception_put "${1#gitception://}" "$2" < "$3"
fi
}
# Put all PUT changes for repo $1 at once
PUT_FINAL()
{
if isurl sftp "$1" || islocalrepo "$1" || isurl rsync "$1"
then
:
else
git push --quiet -f "${1#gitception://}" "$Gref:$Gref_rbranch"
fi
}
# Put directory for repo $1
PUTREPO()
{
if isurl sftp "$1"
then
:
elif isurl rsync "$1"
then
rsync -q -r --exclude='*' "$Localdir/" "${1#rsync://}" >&2
elif islocalrepo "$1"
then
mkdir -p "$1"
else
gitception_new_repo "${1#gitception://}"
fi
}
# For repo $1, delete all newline-separated files in $2
REMOVE()
{
local fn_=
if isurl sftp "$1"
then
# FIXME
echo_info "sftp: Ignore remove request $1/$2"
elif isurl rsync "$1"
then
xecho "$2" | rsync -I -W -v -r --delete --include-from=- \
--exclude='*' "$Localdir"/ "${1#rsync://}/" >&2
elif islocalrepo "$1"
then
for fn_ in $2; do
rm -f "$1"/"$fn_"
done
else
for fn_ in $2; do
gitception_remove "${1#gitception://}" "$fn_"
done
fi
}
CLEAN_FINAL()
{
if isurl sftp "$1" || islocalrepo "$1" || isurl rsync "$1"
then
:
else
git update-ref -d "$Gref" || :
fi
}
addsignkeyparam()
{
if isnull "$Conf_signkey"; then
"$@"
else
"$@" -u "$Conf_signkey"
fi
}
ENCRYPT()
{
gpg --batch --force-mdc --compress-algo none --passphrase-fd 3 -c 3<<EOF
$1
EOF
}
DECRYPT()
{
gpg -q --batch --no-default-keyring --secret-keyring /dev/null \
--keyring /dev/null --passphrase-fd 3 -d 3<<EOF
$1
EOF
}
# Encrypt to recipients $1
PRIVENCRYPT()
{
addsignkeyparam gpg --compress-algo none -se $1
}
PRIVDECRYPT()
{
local status_=
exec 4>&1 &&
status_=$(gpg --status-fd 3 -q -d 3>&1 1>&4) &&
xecho "$status_" | grep "^\[GNUPG:\] ENC_TO " >/dev/null &&
(xecho "$status_" | grep -e "$Goodsig" >/dev/null || {
echo_info "Failed to verify manifest signature!" &&
echo_info "Only accepting signatories: ${Signers:-(none)}" &&
return 1
})
}
# Generate $1 random bytes
genkey()
{
gpg --armor --gen-rand 1 "$1"
}
gpg_hash()
{
local hash_=
hash_=$(gpg --with-colons --print-md "$1" | tr A-F a-f)
hash_=${hash_#:*:}
xecho "${hash_%:}"
}
pack_hash() { gpg_hash "$Hashtype"; }
# Pass the branch/ref by pipe to git
safe_git_rev_parse()
{
git cat-file --batch-check 2>/dev/null |
xgrep -v "missing" | cut -f 1 -d ' '
}
make_new_repo()
{
local urlid_= fix_config=
echo_info "Setting up new repository"
PUTREPO "$URL"
# Needed assumption: the same user should have no duplicate Repoid
Repoid=":id:$(genkey 15)"
iseq "${NAME#gcrypt::}" "$URL" || {
git config "remote.$NAME.gcrypt-id" "$Repoid"
fix_config=1
}
echo_info "Remote ID is $Repoid"
Extension_list=$(xecho "extn comment")
#isnull "$fix_config" || echo_info "(configuration for $NAME updated)"
}
read_config()
{
local recp_= key_line= cap_= conf_keyring= conf_part=
Conf_signkey=$(git config --path user.signingkey || :)
conf_keyring=$(git config --path gcrypt.keyring || :)
conf_part=$(git config --get "remote.$NAME.gcrypt-participants" '.+' ||
git config --get gcrypt.participants '.+' || :)
# Figure out which keys we should encrypt to or accept signatures from
if isnonnull "$conf_keyring" && isnull "$conf_part"
then
echo_info "WARNING: Setting gcrypt.keyring is deprecated," \
"use gcrypt.participants instead."
conf_part=$(gpg --no-default-keyring --keyring "$conf_keyring" \
--with-colons --fast-list -k | grep ^pub | cut -f 5 -d :)
fi
if isnull "$conf_part" || iseq "$conf_part" simple
then
Signers="(default keyring)"
Recipients="--throw-keyids --default-recipient-self"
Goodsig="^\[GNUPG:\] GOODSIG "
return 0
fi
for recp_ in $conf_part
do
key_line=$(gpg --with-colons --fast-list -k "$recp_" | xgrep ^pub)
keyid_=$(xecho "$key_line" | cut -f 5 -d :)
isnonnull "$keyid_" &&
Signers="$Signers $keyid_" &&
Goodsig=$(append "$Goodsig" "^\[GNUPG:\] GOODSIG $keyid_") || {
echo_info "WARNING: Skipping missing key $recp_"
continue
}
# Check 'E'ncrypt capability
cap_=$(xecho "$key_line" | cut -f 12 -d :)
iseq "${cap_#*E}" "$cap_" || Recipients="$Recipients -R $keyid_"
done
if isnull "$Recipients"
then
echo_info "You have not configured any keys to encrypt to for this repository"
echo_info "Use ::"
echo_info " git config gcrypt.participants YOURKEYID"
exit 1
fi
}
ensure_connected()
{
local manifest_= rcv_repoid= r_name= url_frag=
if isnonnull "$Did_find_repo"
then
return
fi
Did_find_repo=no
read_config
iseq "${NAME#gcrypt::}" "$URL" || r_name=$NAME
# Fixup ssh:// -> rsync://
if isurl ssh "$URL"; then
URL="rsync://${URL#ssh://}"
isnull "$r_name" || {
git config "remote.$r_name.url" "gcrypt::$URL"
echo_info "Updated URL for $r_name, ssh: -> rsync:"
}
fi
if isurl gitception "$URL" && isnonnull "$r_name"; then
git config "remote.$r_name.url" "gcrypt::${URL#gitception://}"
echo_info "Updated URL for $r_name, gitception:// -> ()"
fi
# Find the URL fragment
url_frag=${URL##*"#"}
isnoteq "$url_frag" "$URL" || url_frag=
isnonnull "$url_frag" || {
# find old style /G.XXXXXX fragment
url_frag=${URL##*/G.}
if isnoteq "$url_frag" "$URL"; then
URL=${URL%/G."$url_frag"}
isnull "$r_name" || {
git config "remote.$r_name.url" \
"gcrypt::$URL#$url_frag"
echo_info "Updated URL for $r_name, use #fragment"
}
else
url_frag=
fi
}
URL=${URL%"#$url_frag"}
# manifestfile -- sha224 hash if we can, else the default location
if isurl sftp "$URL" || islocalrepo "$URL" || isurl rsync "$URL"
then
# not for gitception
isnull "$url_frag" ||
Manifestfile=$(xecho_n "$url_frag" | gpg_hash SHA224)
else
isnull "$url_frag" || Gref_rbranch="refs/heads/$url_frag"
fi
Repoid=
isnull "$r_name" || {
Repoid=$(git config "remote.$r_name.gcrypt-id" || :)
}
TmpManifest_Enc="$Localdir/tmp_manifest.$$"
GET "$URL" "$Manifestfile" "$TmpManifest_Enc" 2>/dev/null || {
echo_info "Repository not found: $URL"
return 0
}
Did_find_repo=yes
echo_info "Decrypting manifest"
manifest_=$(PRIVDECRYPT < "$TmpManifest_Enc") &&
isnonnull "$manifest_" ||
echo_die "Failed to decrypt manifest!"
rm -f "$TmpManifest_Enc"
Branchlist=$(xecho "$manifest_" | xgrep -E '^[0-9a-f]{40} ')
Packlist=$(xecho "$manifest_" | xgrep "^pack ")
Keeplist=$(xecho "$manifest_" | xgrep "^keep ")
Extension_list=$(xecho "$manifest_" | xgrep "^extn ")
rcv_repoid=$(xecho "$manifest_" | xgrep "^repo ")
rcv_repoid=${rcv_repoid#repo }
rcv_repoid=${rcv_repoid% *}
if isnull "$Repoid"
then
echo_info "Remote ID is $rcv_repoid"
Repoid=$rcv_repoid
elif isnoteq "$rcv_repoid" "$Repoid"
then
echo_info "WARNING:"
echo_info "WARNING: Remote ID has changed!"
echo_info "WARNING: from $Repoid"
echo_info "WARNING: to $rcv_repoid"
echo_info "WARNING:"
Repoid=$rcv_repoid
else
return 0
fi
isnull "$r_name" || {
git config "remote.$r_name.gcrypt-id" "$rcv_repoid"
}
}
fetch_decrypt_pack()
{
local key_= rcv_id= htype_= pack_= hfunc_=
splitcolon "${1#pack :}"
htype_=$prefix_
pack_=$suffix_
if isnoteq "$htype_" SHA256 && isnoteq "$htype_" SHA224 &&
isnoteq "$htype_" SHA384 && isnoteq "$htype_" SHA512
then
echo_die "Packline malformed: $1"
fi
GET "$URL" "$pack_" "$TmpPack_Encrypted" &&
rcv_id=$(gpg_hash "$htype_" < "$TmpPack_Encrypted") &&
iseq "$rcv_id" "$pack_" ||
echo_die "Packfile $pack_ does not match digest!"
key_=$(xecho "$Packlist" | grep "$pack_" | cut -f 3 -d ' ')
DECRYPT "$key_" < "$TmpPack_Encrypted"
}
# $1 is new pack id $2 key
# set did_repack=yes if repacked
repack_if_needed()
{
local pack_= packline_= premote_= key_= pkeep_= n_=
# $TmpPack_Encrypted set in caller
did_repack=no
isnonnull "$Packlist" || return 0
if isnonnull "$GCRYPT_FULL_REPACK"
then
Keeplist=
Repack_limit=1
fi
premote_=$(xecho "$Packlist" | cut -f 1-2 -d ' ')
pkeep_=$(xecho "$Keeplist" | cut -f 2 -d ' ')
if isnull "$pkeep_"; then
n_=$(xecho "$Packlist" | wc -l)
else
n_=$(xecho "$Packlist" | grep -v -e "$pkeep_" | wc -l)
fi
if [ $Repack_limit -gt "$n_" ]; then
return
fi
echo_info "Repacking remote $NAME, ..."
rm -r -f "$Localdir/pack"
mkdir -p "$Localdir/pack"
DECRYPT "$2" < "$TmpPack_Encrypted" |
git index-pack -v --stdin "$Localdir/pack/${1}.pack" >/dev/null
xecho "$premote_" | while read packline_
do
isnonnull "$packline_" || continue
if isnonnull "$pkeep_" &&
xecho "$packline_" | grep -q -e "$pkeep_"
then
continue
fi
pack_=${packline_#$Packpat}
fetch_decrypt_pack "$packline_" |
git index-pack -v --stdin "$Localdir/pack/${pack_}.pack" >/dev/null
done
key_=$(genkey "$Packkey_bytes")
git verify-pack -v "$Localdir"/pack/*.idx | grep -E '^[0-9a-f]{40}' |
cut -f 1 -d ' ' |
GIT_ALTERNATE_OBJECT_DIRECTORIES=$Localdir \
git pack-objects --stdout | ENCRYPT "$key_" > "$TmpPack_Encrypted"
# Truncate packlist to only the kept packs
if isnull "$pkeep_"; then
Packlist_delete=$premote_
Packlist=
else
Packlist_delete=$(xecho "$premote_" | xgrep -v -e "$pkeep_")
Packlist=$(xecho "$Packlist" | xgrep -e "$pkeep_")
fi
pack_id=$(pack_hash < "$TmpPack_Encrypted")
Packlist=$(append "$Packlist" "pack :${Hashtype}:$pack_id $key_")
Keeplist=$(append "$Keeplist" "keep :${Hashtype}:$pack_id 1")
rm -r -f "$Localdir/pack"
did_repack=yes
}
do_capabilities()
{
echo_git fetch
echo_git push
echo_git
}
do_list()
{
local obj_id= ref_name= line_=
ensure_connected
xecho "$Branchlist" | while read line_
do
isnonnull "$line_" || break
obj_id=${line_%% *}
ref_name=${line_##* }
echo_git "$obj_id" "$ref_name"
if iseq "$ref_name" "refs/heads/master"
then
echo_git "@refs/heads/master HEAD"
fi
done
# end with blank line
echo_git
}
do_fetch()
{
# The PACK id is the hash of the encrypted git packfile.
# We only download packs mentioned in the encrypted manifest,
# and check their digest when received.
local pack_= packline_= pneed_= phave_= premote_=
ensure_connected
if isnull "$Packlist"
then
echo_git # end with blank line
return
fi
TmpPack_Encrypted="$Localdir/tmp_pack_ENCRYPTED_.$$"
premote_=$(xecho "$Packlist" | cut -f 1-2 -d ' ')
# The `+` for $GITCEPTION is pointless but we will be safe for stacking
phave_="$(cat "$Localdir/have_packs+" 2>/dev/null || :)"
pneed_="$(xecho "$premote_" | xgrep -v -x -e "$phave_")"
xecho "$pneed_" | while read packline_
do
isnonnull "$packline_" || continue
fetch_decrypt_pack "$packline_" |
git index-pack -v --stdin >/dev/null
# add to local pack list
xecho "${packline_}" >> "$Localdir/have_packs$GITCEPTION"
done
rm -f "$TmpPack_Encrypted"
echo_git # end with blank line
}
# do_push PUSHARGS (multiple lines like +src:dst, with both + and src opt.)
do_push()
{
# Security protocol:
# Each git packfile is encrypted and then named for the encrypted
# file's hash. The manifest is updated with the pack id.
# The manifest is encrypted.
local remote_has= remote_want= prefix_= suffix_= line_= pack_id= key_=
del_hash=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
ensure_connected
if iseq "$Did_find_repo" "no"
then
make_new_repo
fi
if isnonnull "$Branchlist"
then
# filter through batch-check to mark only the commits we have
remote_has=$(xecho "$Branchlist" | cut -f 1 -d ' ' |
safe_git_rev_parse | sed -e 's/^\(.\)/^&/')
fi
while read line_ # from <<
do
# +src:dst -- remove leading + then split at :
splitcolon "${line_#+}"
if isnonnull "$prefix_"
then
remote_want=$(append "$remote_want" "$prefix_")
Branchlist=$(append "$Branchlist" \
"$(xecho "$prefix_" | safe_git_rev_parse) $suffix_")
else
# Mark branch for deletion
Branchlist=$(append "$Branchlist" "$del_hash $suffix_")
fi
done <<EOF
$1
EOF
Branchlist=$(xecho "$Branchlist" | sort_stable_k2 | tac | uniq -s 40 |
xgrep -v "^$del_hash")
TmpPack_Encrypted="$Localdir/tmp_pack_ENCRYPTED_.$$"
TmpObjlist="$Localdir/tmp_packrevlist.$$"
key_=$(genkey "$Packkey_bytes")
append "$remote_has" "$remote_want" |
git rev-list --objects --stdin -- |
tee "$TmpObjlist" |
git pack-objects --stdout | ENCRYPT "$key_">"$TmpPack_Encrypted"
# Only send pack if we have any objects to send
if [ -s "$TmpObjlist" ]
then
pack_id=$(pack_hash < "$TmpPack_Encrypted")
did_repack=
repack_if_needed "$pack_id" "$key_"
if isnoteq "$did_repack" yes
then
Packlist=$(append "$Packlist" "pack :${Hashtype}:$pack_id $key_")
fi
# else, repack rewrote Packlist
fi
# Generate manifest
echo_info "Encrypting to: $Recipients"
echo_info "Requesting manifest signature"
TmpManifest_Enc="$Localdir/tmp_manifest.$$"
(xecho "$Branchlist"; xecho "$Packlist"; xecho "$Keeplist";
repoidstr; xecho "$Extension_list") |
PRIVENCRYPT "$Recipients" > "$TmpManifest_Enc"
# Upload pack
if [ -s "$TmpObjlist" ]
then
PUT "$URL" "$pack_id" "$TmpPack_Encrypted"
fi
rm -f "$TmpPack_Encrypted"
rm -f "$TmpObjlist"
# Upload manifest
PUT "$URL" "$Manifestfile" "$TmpManifest_Enc"
# Delete packs
if isnonnull "$Packlist_delete"; then
REMOVE "$URL" "$(xecho "$Packlist_delete" | while read packline_
do
isnonnull "$packline_" || continue
pack_=${packline_#$Packpat}
xecho "$pack_"
done)"
fi
PUT_FINAL "$URL"
rm -f "$TmpManifest_Enc"
# ok all updates
xecho "$1" | while read line_
do
# +src:dst -- remove leading + then split at :
splitcolon "${line_#+}"
echo_git "ok $suffix_"
done
echo_git
}
NAME=$1 # Remote name
URL=$2 # Remote URL
mkdir -p "$Localdir"
trap 'rm -f "$Localdir/tmp_"*".$$"' EXIT 1 2 3 15
echo_info "Development version -- Repository format MAY CHANGE"
while read Input
do
case "$Input" in
capabilities)
do_capabilities
;;
list|list\ for-push)
do_list
;;
fetch\ *)
args_="${Input##fetch }"
while read InputX
do
case "$InputX" in
fetch*)
args_= #ignored
;;
*)
break
;;
esac
done
do_fetch "$args_"
;;
push\ *)
args_="${Input##push }"
while read InputX
do
case "$InputX" in
push\ *)
args_=$(append "$args_" "${InputX#push }")
;;
*)
break
;;
esac
done
do_push "$args_"
;;
?*)
echo_die "Unknown input!"
;;
*)
CLEAN_FINAL "$URL"
exit 0
;;
esac
done