git remote add cryptremote gcrypt::rsync://example.com:repo
git push cryptremote master
> gcrypt: Setting up new repository
- > gcrypt: Repository URL is gcrypt::rsync://example.com:repo#KNBr0wKzct52
- > gcrypt: (configuration for cryptremote updated)
+ > gcrypt: Repository ID is :SHA256:3a29d035adf234af7e[... ]
> [ more lines .. ]
> To gcrypt::[...]
> * [new branch] master -> master
-* Share the updated Repository URL with all participants.
-
-(The generated Repository URL is not secret, it only exists to ensure
-that two repositories signed by the same user can not be maliciously
-switched around. It incidentally allows multiple repositories to all
-share location.)
+(The generated Repository id is not secret, it only exists to ensure
+that two repositories signed by the same user can be distinguished.
+You will see a warning if the remote repository ID changes, which will
+only happen if the remote was re-created or switched out.)
Design Goals
............
How to use a git backend::
# notice that the target repo must already exist and its
- # `master` branch will be overwritten!
- git remote add gitcrypt gcrypt::git@example.com:repo
+ # `next` branch will be overwritten!
+ git remote add gitcrypt gcrypt::git@example.com:repo#next
git push gitcrypt HEAD
+The URL fragment (`#next` here) indicates which branch is used.
+
Notes
=====
EncSign(X) is sign+encrypt to a PGP key holder
Encrypt(K,X) is symmetric encryption
- Hash(X) is SHA-224
+ Hash(X) is SHA-256
B: branch list
L: list of the hash (Hi) and key (Ki) for each packfile
- R: Hash(Repository ID)
+ R: repository id
- Store Manifest as EncSign(B || L || R) in filename R
+ Store Manifest as EncSign(B || L || R)
Store each packfile P as P' = Encrypt(Ki, P) in filename Hi
where Hi = Hash(P') and Ki is a random string
To read the repository
decrypt+verify Manifest using private key -> (B, L, R)
- verify R matches Hash(Requested Repository ID)
+ warn if R does not match saved repository id for this remote
for Hi, Ki in L:
download file Hi from the server -> P'
verify Hash(P') matches Hi
::
- $ gpg -d < 5a191cea8c1021a95d813c4007c14f2cc987a40880c2f669430f1916
- b4a4a39365d19282810c19d0f3f24d04dd2d179f refs/tags/version1
- 1d323ddadf4cf1d80fced447e637ab3766b168b7 refs/heads/master
- pack :SHA224:cfdf36515e0d0820554fe5fd9f00a4bee17bcf88ec8a752d851c46ee \
- Rc+j8Nv6GOW3mBhWOx6W6jjz3BTX7B6XIJ6RYI+P4TEy
- pack :SHA224:a43ccd208d3bd2ea582dbd5407cb8ed6e18b150b1da25c806115eaa5 \
- UXR3/R7awFCUJWYdzXzrlkk7E2Acxq/Y4EfEcd62AwGG
- repo :SHA224:5a191cea8c1021a95d813c4007c14f2cc987a40880c2f669430f1916 1
+ $ gpg -d 91bd0c092128cf2e60e1a608c31e92caf1f9c1595f83f2890ef17c0e4881aa0a
+ 542051c7cd152644e4995bda63cc3ddffd635958 refs/heads/next
+ 3c9e76484c7596eff70b21cbe58408b2774bedad refs/heads/master
+ pack :SHA256:f2ad50316fbca42c553810aec3709c24974585ec1b34aae77d5cd4ba67092dc4 z8YoAnFpMlWPIYG8wo1adewd4Fp7Fo3PkI2mND49P1qm
+ pack :SHA256:a6e17bb4c042bdfa8e38856ee6d058d0c0f0c575ace857c4795426492f379584 82+k2cbiUn7i2cW0dgXfyX6wXGpvVaQGj5sF59Y8my5W
+ keep :SHA256:f2ad50316fbca42c553810aec3709c24974585ec1b34aae77d5cd4ba67092dc4 1
+ repo :SHA256:ef8e52a7ea96761f713c14caa7190b5f3b55ff87ffe091cab40f7cbe1d3b5b96
Each item extends until newline, and matches one of the following forms:
`keep :<hashtype>:<hash> <generation>`
Packfile hash and its repack generation
- `repo :<hashtype>:<hash> <version>`
- The hash of the repository id.
+ `repo :<hashtype>:<hash>`
+ The repository id
`extn <name> ...`
Extension field, preserved but unused.
Yet to be Implemented
.....................
-+ Repacking the remote repository
+ Some kind of simple keyring management
See Also
Gref_rbranch="refs/heads/master"
Repoid=
Packkey_bytes=33 # 33 random bytes for passphrase, still compatible if changed
-Hashtype=SHA224 # incompatible if changed
-Packpfx="pack :${Hashtype}:"
-Keeppfx="keep :${Hashtype}:"
+Hashtype=SHA256 # SHA512 SHA384 SHA256 SHA224 supported.
+Packpat="pack :*:"
+Manifestfile=91bd0c092128cf2e60e1a608c31e92caf1f9c1595f83f2890ef17c0e4881aa0a
+Urlfrag=
Branchlist=
Packlist=
prefix_=${1%%:*}
suffix_=${1#*:}
}
-repoidstr() { xecho "repo :${Hashtype}:$Repoid 1"; }
+repoidstr() { xecho "repo $Repoid"; }
## gitception part
# Fetch giturl $1, file $2
# Take care to preserve FETCH_HEAD
local ret_=: obj_id= f_head="$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 &&
+ git fetch -q -f "$1" "refs/heads/${Urlfrag:-master}:$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 && : ; }
then
:
else
- git push --quiet -f "${1#gitception://}" "$Gref:$Gref_rbranch"
+ git push --quiet -f "${1#gitception://}" \
+ "$Gref:refs/heads/${Urlfrag:-master}"
fi
}
gpg --armor --gen-rand 1 "$1"
}
-pack_hash()
+gpg_hash()
{
local hash_=
- hash_=$(gpg --with-colons --print-md "$Hashtype" | tr A-F a-f)
+ 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()
{
echo_info "Setting up new repository"
PUTREPO "$URL"
- # We need a relatively short ID for URL+REPO
- # The manifest will be stored at pack_hash($urlid_)
- # Needed assumption: the same user should have no duplicate urlid_
- # For now, we arbitrarily use 9 random bytes (72 bits)
- urlid_=$(genkey 9 | tr '+/' '-_')
- Repoid=$(xecho_n "$urlid_" | pack_hash)
+ # Needed assumption: the same user should have no duplicate Repoid
+ Repoid=":${Hashtype}:$(genkey 64 | pack_hash)"
iseq "${NAME#gcrypt::}" "$URL" || {
- git config "remote.$NAME.url" "gcrypt::$URL#$urlid_"
+ git config "remote.$NAME.gcrypt-id" "$Repoid"
fix_config=1
}
- echo_info "Repository URL is" "gcrypt::$URL#$urlid_"
+ echo_info "Repository ID is $Repoid"
Extension_list=$(xecho "extn comment")
- isnull "$fix_config" || echo_info "(configuration for $NAME updated)"
+ #isnull "$fix_config" || echo_info "(configuration for $NAME updated)"
}
ensure_connected()
{
- local manifest_= rcv_repoid= url_id=
+ local manifest_= rcv_repoid= r_name=
if isnonnull "$Did_find_repo"
then
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://}"
fi
- # split out Repo ID from URL
- url_id=${URL##*"#"}
- isnoteq "$url_id" "$URL" || {
- url_id=${URL##*/"G."}
- isnoteq "$url_id" "$URL" || return 0
- URL=${URL%/"G.$url_id"}
+ # Find the URL fragment
+ Urlfrag=${URL##*"#"}
+ isnoteq "$Urlfrag" "$URL" || Urlfrag=
+ URL=${URL%"#$Urlfrag"}
+
+ # manifestfile -- sha224 hash if we can, else the default location
+ if isurl sftp "$URL" || islocalrepo "$URL" || isurl rsync "$URL"
+ then
+ # not for gitception
+ isnull "$Urlfrag" || Manifestfile=$(xecho_n "$Urlfrag" | gpg_hash SHA224)
+ fi
+
+ Repoid=
+ isnull "$r_name" || {
+ Repoid=$(git config "remote.$r_name.gcrypt-id" || :)
}
- URL=${URL%"#$url_id"}
- Repoid=$(xecho_n "$url_id" | pack_hash)
+
TmpManifest_Enc="$Localdir/tmp_manifest.$$"
- GET "$URL" "$Repoid" "$TmpManifest_Enc" 2>/dev/null ||
- echo_die "Repository not found: $url_id at $URL"
+ GET "$URL" "$Manifestfile" "$TmpManifest_Enc" 2>/dev/null || {
+ echo_info "Repository not found: $URL"
+ return 0
+ }
Did_find_repo=yes
echo_info "Decrypting manifest"
rm -f "$TmpManifest_Enc"
Branchlist=$(xecho "$manifest_" | xgrep -E '^[0-9a-f]{40} ')
- Packlist=$(xecho "$manifest_" | xgrep "^$Packpfx")
- Keeplist=$(xecho "$manifest_" | xgrep "^keep")
+ Packlist=$(xecho "$manifest_" | xgrep "^pack ")
+ Keeplist=$(xecho "$manifest_" | xgrep "^keep ")
Extension_list=$(xecho "$manifest_" | xgrep "^extn ")
rcv_repoid=$(xecho "$manifest_" | xgrep "^repo ")
- iseq "$(repoidstr)" "$rcv_repoid" || echo_die "Repository id mismatch!"
+
+ rcv_repoid=${rcv_repoid#repo }
+ rcv_repoid=${rcv_repoid% *}
+ if isnull "$Repoid"
+ then
+ echo_info "Remote repo ID is $rcv_repoid"
+ Repoid=$rcv_repoid
+ elif isnoteq "$rcv_repoid" "$Repoid"
+ then
+ echo_info "WARNING:"
+ echo_info "WARNING: Remote repository ID has changed!"
+ 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" "$rcv_repoid"
+ }
}
fetch_decrypt_pack()
{
- local key_= rcv_id=
- GET "$URL" "$1" "$TmpPack_Encrypted" &&
- rcv_id=$(pack_hash < "$TmpPack_Encrypted") &&
- iseq "$rcv_id" "$1" ||
- echo_die "Packfile $1 does not match digest!"
- key_=$(xecho "$Packlist" | grep "$1" | cut -f 3 -d ' ')
+ local key_= rcv_id= htype_= pack_= hfunc_=
+ splitcolon "${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"
}
then
continue
fi
- pack_=${packline_#"$Packpfx"}
- fetch_decrypt_pack "$pack_" |
+ pack_=${packline_#$Packpat}
+ fetch_decrypt_pack "$packline_" |
git index-pack -v --stdin "$Localdir/pack/${pack_}.pack" >/dev/null
done
key_=$(genkey "$Packkey_bytes")
fi
pack_id=$(pack_hash < "$TmpPack_Encrypted")
- Packlist=$(append "$Packlist" "$Packpfx$pack_id $key_")
- Keeplist=$(append "$Keeplist" "$Keeppfx$pack_id 1")
+ Packlist=$(append "$Packlist" "pack :${Hashtype}:$pack_id $key_")
+ Keeplist=$(append "$Keeplist" "keep :${Hashtype}:$pack_id 1")
rm -r -f "$Localdir/pack"
did_repack=yes
}
xecho "$pneed_" | while read packline_
do
isnonnull "$packline_" || continue
- pack_=${packline_#"$Packpfx"}
- fetch_decrypt_pack "$pack_" |
+ fetch_decrypt_pack "$packline_" |
git index-pack -v --stdin >/dev/null
# add to local pack list
- xecho "$Packpfx$pack_" >> "$Localdir/have_packs$GITCEPTION"
+ xecho "${packline_}" >> "$Localdir/have_packs$GITCEPTION"
done
rm -f "$TmpPack_Encrypted"
if isnoteq "$did_repack" yes
then
- Packlist=$(append "$Packlist" "$Packpfx$pack_id $key_")
+ Packlist=$(append "$Packlist" "pack :${Hashtype}:$pack_id $key_")
fi
# else, repack rewrote Packlist
rm -f "$TmpObjlist"
# Upload manifest
- PUT "$URL" "$Repoid" "$TmpManifest_Enc"
+ PUT "$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_#"$Packpfx"}
+ pack_=${packline_#$Packpat}
xecho "$pack_"
done)"
fi
projects / gamesguru / git-remote-gcrypt.git / commitdiff