Adarsh-Me commented on code in PR #3192: URL: https://github.com/apache/hugegraph/pull/3192#discussion_r4223127529
########## hugegraph-server/hugegraph-dist/src/assembly/static/bin/props.awk: ########## @@ -0,0 +1,423 @@ +# Licensed to the Apache Software Foundation (ASF) under one or more +# contributor license agreements. See the NOTICE file distributed with +# this work for additional information regarding copyright ownership. +# The ASF licenses this file to You under the Apache License, Version 2.0 +# (the "License"); you may not use this file except in compliance with +# the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. +# +# props.awk — read and rewrite Java ".properties" files with the grammar +# HugeConfig (commons-configuration over JDK Properties) applies, so the +# entrypoint and the server agree on what a mounted file means. grep/sed +# rewrites do not: they see `\`-escaped keys, `:` separators, continuation +# lines and duplicate definitions differently, which is how a mounted +# config ends up with two definitions of one key. +# +# One invocation, selected with the `PROPS_MODE` environment variable: +# +# PROPS_MODE=get PROPS_KEY=K PROPS_FILE=F +# print the value of K's first logical definition, in the on-disk +# escaped form; with PROPS_DECODED=1 print it as java.util.Properties +# would hand it to the server. Always exits 0. +# PROPS_MODE=has PROPS_KEY=K PROPS_FILE=F +# print nothing; exit 0 when K has any definition at all, empty +# included, 1 when it has none, 2 on an error +# PROPS_MODE=set PROPS_KEY=K PROPS_FILE=F +# replace K's first definition in place, drop every other +# definition of K, append one when the file has none. The new +# value arrives pre-encoded in PROPS_VALUE_ENCODED (an environment +# variable, so secrets never appear in `ps` output or in awk's +# argv), and -v is not used for it so awk cannot mangle its +# backslash escapes. +# +# Grammar implemented (java.util.Properties line reader + the +# first-definition-wins rule Configuration.getString applies): +# - physical lines end at \r\n, \n or a bare \r, as in java.util.Properties +# - '#' / '!' comments and blank lines +# - '=' / ':' / whitespace separators, where the whitespace Java counts is +# space, tab and form feed, with whitespace then an optional single '=' or +# ':' accepted as one separator +# - continuations: a physical line ending in an odd number of +# backslashes joins the next line (its leading whitespace stripped) +# - backslash escapes in keys and values, including \uXXXX +# - duplicate logical keys resolve to the first definition +# +# Rewrites keep every untouched line byte-for-byte (comments, blank +# lines, unrelated entries), and replace the first definition where it +# stands, so mounted configs stay reviewable in git diffs. +# +# A file that carries commons-configuration's `include` directive is refused in +# every mode, with exit status 2: the directive splices another file into this +# one, so "this key is absent" is a question that cannot be answered from this +# file alone, and writing into it could bury the definition the server reads. +# Rewrites stage through two exclusively created 0600 files (`mktemp`) rather +# than a predictable `<file>.tmp` / `<file>.bak`, which a writer in a mounted +# conf directory could have arranged as a symlink before the entrypoint, running +# as root, opened either of them. + +function die(msg) { + printf "props.awk: %s\n", msg > "/dev/stderr" + # 2 for an error, so a caller that reads exit status 1 as "the key is not + # there" (PROPS_MODE=has) cannot mistake an unreadable file for an absent + # property and append a definition on top of one it failed to read. + exit 2 +} + +function hex_digit(c) { + return index("0123456789abcdef", tolower(c)) - 1 +} + +# \uXXXX is a UTF-16 code unit in Java. Values here are effectively +# ISO-8859-1, so codes above 0xFF are kept as their literal escape text +# rather than being mangled through a single-byte sprintf. +function unescape(s, out, i, n, c, code, j, d, ok) { + out = "" + n = length(s) + for (i = 1; i <= n; i++) { + c = substr(s, i, 1) + if (c != "\\") { out = out c; continue } + if (i == n) break + i++ + c = substr(s, i, 1) + if (c == "u" && i + 4 <= n) { + code = 0 + ok = 1 + for (j = 1; j <= 4; j++) { + d = hex_digit(substr(s, i + j, 1)) + if (d < 0) { ok = 0; break } + code = code * 16 + d + } + if (ok) { + i += 4 + if (code <= 255) out = out sprintf("%c", code) + else out = out substr(s, i - 5, 6) + continue + } + } + if (c == "t") out = out "\t" + else if (c == "n") out = out "\n" + else if (c == "r") out = out "\r" + else if (c == "f") out = out "\f" + else out = out c + } + return out +} + +# A physical line is continued when it ends in an odd number of +# backslashes (an even count escapes itself). +function trailing_backslashes(s, n, k) { + n = length(s) + k = 0 + while (k < n && substr(s, n - k, 1) == "\\") k++ + return k +} + +function is_skipped(raw) { + return raw ~ /^[ \t\f]*([#!]|$)/ +} + +# Split a logical line into its raw (still-escaped) key and value parts. +# Results land in K_RAW / V_RAW because awk returns one value. +# Java treats form feed as whitespace on both sides of the separator, so +# `auth.authenticator<FF>=...` is one property here too; reading it as part of +# the key name made a valid mounted configuration invisible to the guards. +function split_kv(s, n, i, c, esc, sep_at, rest) { + n = length(s) + esc = 0 + sep_at = 0 + for (i = 1; i <= n; i++) { + c = substr(s, i, 1) + if (esc) { esc = 0; continue } + if (c == "\\") { esc = 1; continue } + if (c == "=" || c == ":" || c == " " || c == "\t" || c == "\f") { sep_at = i; break } + } + if (sep_at == 0) { + K_RAW = s + V_RAW = "" + return + } + K_RAW = substr(s, 1, sep_at - 1) + rest = substr(s, sep_at) + c = substr(rest, 1, 1) + if (c == "=" || c == ":") { + rest = substr(rest, 2) + } else { + sub(/^[ \t\f]+/, "", rest) + c = substr(rest, 1, 1) + if (c == "=" || c == ":") rest = substr(rest, 2) + } + sub(/^[ \t\f]+/, "", rest) + V_RAW = rest +} + +function shquote(s) { + gsub(/'/, "'\\''", s) + return "'" s "'" +} + +# A private temporary file, created exclusively, beside `file`. +# +# The name has to come from mktemp. With a fixed `<file>.tmp` anyone able to +# write in a mounted conf directory could leave that name as a symlink to a +# file elsewhere in the container, and neither the shell redirection that +# pre-created it nor awk's own `>` checks for that: both follow it, so the +# entrypoint, running as root by default, would write auth.admin_pa or +# auth.token_secret through the link and into whatever it points at. An +# exclusive create of an unpredictable name cannot be pre-arranged, and mktemp +# makes the file 0600 whatever the umask says, which is the reason no chmod +# follows it here. +# +# The template is quoted, which is also why no `--` is passed: the argument +# starts at a quote byte, so it can never read as an option. +function make_temp(file, kind, cmd, path) { + path = "" + cmd = "umask 077 && mktemp " shquote(file) "." kind ".XXXXXX" + if ((cmd | getline path) <= 0 || path == "") { + close(cmd) + die("cannot create a private " kind " file beside " file) + } + close(cmd) + return path +} + +# java.util.Properties ends a physical line at \r\n, \n or a bare \r, but +# getline splits on \n alone. A properties file saved with CR-only endings -- +# which java.util.Properties writes for a lone `store()` on some platforms, and +# which a mounted config can arrive with -- therefore reached the parser as one +# enormous record: only its first key was ever seen, and rewriting that key +# replaced the whole record and dropped every later entry, including +# auth.authenticator. So the file is re-scanned for terminators here. +# +# RAW[] keeps the exact bytes of each line and RAWTERM[] its terminator, so a +# rewrite still replays untouched lines byte-for-byte. A file whose last line +# carries no terminator gets a \n, which is what the replay did before. +function scan_records(s, i, n, c, start, term, len, cnt) { + n = length(s) + cnt = 0 + start = 1 + i = 1 + while (i <= n) { + c = substr(s, i, 1) + if (c != "\r" && c != "\n") { i++; continue } + if (c == "\r" && substr(s, i + 1, 1) == "\n") { + term = "\r\n" + len = 2 + } else { + term = c + len = 1 + } + cnt++ + RAW[cnt] = substr(s, start, i - start) + RAWTERM[cnt] = term + start = i + len + i = start + } + if (start <= n) { + cnt++ + RAW[cnt] = substr(s, start) + RAWTERM[cnt] = "" + } + return cnt +} + +# Load `file` into per-block arrays: one block per comment/blank line or +# logical entry, spanning exactly the physical lines it occupies. +function props_load(file, raw, rc, content, nl, stripped, next_raw, start, logical, inc) { + content = "" + while ((rc = (getline raw < file)) > 0) + content = content raw "\n" + if (rc == -1) + die("cannot read " file) + close(file) + + NLINES = scan_records(content) + + NBLOCK = 0 + for (nl = 1; nl <= NLINES; nl++) { + # RAW[] holds one java.util.Properties physical line with its terminator + # already removed, so no CR stripping is needed here. + stripped = RAW[nl] + if (is_skipped(stripped)) { + NBLOCK++ + BTYPE[NBLOCK] = "skip" + BFIRST[NBLOCK] = nl + BLAST[NBLOCK] = nl + continue + } + start = nl + logical = stripped + while (trailing_backslashes(logical) % 2 == 1 && nl < NLINES) { + logical = substr(logical, 1, length(logical) - 1) + nl++ + next_raw = RAW[nl] + sub(/^[ \t\f]+/, "", next_raw) + logical = logical next_raw + } + # java.util.Properties ignores whitespace before the key; strip it + # so split_kv's separator scan agrees (an indented key used to be + # read as a key whose name started with a space, and a set then + # appended a second definition of the real key). + sub(/^[ \t\f]+/, "", logical) + split_kv(logical) + NBLOCK++ + BTYPE[NBLOCK] = "entry" + BFIRST[NBLOCK] = start + BLAST[NBLOCK] = nl + BKEY[NBLOCK] = unescape(K_RAW) + # An include directive is not an ordinary property to the server: commons + # configuration splices the named file into this one at this point, so + # auth.authenticator can be defined over there and be invisible from + # here, and which of the two definitions wins follows the spliced + # order rather than the order of this file. Answering that needs the + # parser the server uses, and answering it wrong is how a mounted + # config boots with REST open and Gremlin protected. Commons + # configuration 2 treats both `include` and `includeOptional` as + # directives, and matches the property name case-insensitively, so the + # guard below rejects every spelling a real loader would honour -- not + # just the exact lowercase `include` this first refused. A file that + # uses any of them is refused in every mode and nothing is written. + inc = tolower(BKEY[NBLOCK]) + if (inc == "include" || inc == "includeoptional") + die("refusing to read or rewrite " file ": it uses an include directive (line " start "), which this helper cannot resolve") + # Values stay in their on-disk escaped form. get Prop callers feed + # the result straight back into set, which would corrupt a decoded + # value by re-writing its backslashes as literals; keys are + # unescaped because they are matched against plain names. + BVAL[NBLOCK] = V_RAW + } +} + +function props_set(file, key, enc_val, tmp, bak, cmd, b, first, ln, msg, nbs, tail) { + props_load(file) + # A value whose written form leaves an odd number of backslashes at the end + # of the physical line turns the line after it into a continuation of that + # value. The line has to be judged as the server sees it: commons + # configuration trims the line before it looks for the continuation, so + # `abc\ ` -- the spelling encode_prop_value used to give a trailing space -- + # reaches the server as `abc\` and swallows whatever follows it. Measured + # against commons-configuration2 (what HugeConfig extends), the same input + # read back yields no property at all, so a secret written this way never + # reaches the server that is supposed to authenticate with it. The + # entrypoint has to refuse instead of guessing a target. + tail = enc_val + sub(/[ \t\f\r]+$/, "", tail) + nbs = 0 + while (nbs < length(tail) && substr(tail, length(tail) - nbs, 1) == "\\") + nbs++ + if (nbs % 2 == 1) + die("refusing to write " key ": trimmed of its trailing blanks the value ends in a backslash, which would swallow the next line") + first = 0 + for (b = 1; b <= NBLOCK; b++) { + if (BTYPE[b] == "entry" && BKEY[b] == key) { + if (first == 0) first = b + else BDROP[b] = 1 + } + } + # Staged rewrite: everything lands in a private temp file first, so a + # failure before the copy-back leaves the original untouched. The temp file + # holds secrets, so it is created 0600 and exclusively (see make_temp): a + # reused, predictable name is both a disclosure risk under the process umask + # and a path someone else can have arranged already. + tmp = make_temp(file, "tmp") + for (b = 1; b <= NBLOCK; b++) { + if (BDROP[b]) continue + if (b == first) { + printf "%s=%s\n", key, enc_val > tmp + } else { + for (ln = BFIRST[b]; ln <= BLAST[b]; ln++) { + # Replay the line with the terminator it was read with, so a + # CRLF or CR-only config keeps its endings on lines the + # rewrite does not touch. + msg = RAWTERM[ln] + if (msg == "") msg = "\n" + printf "%s%s", RAW[ln], msg > tmp + } + } + } + if (first == 0) + printf "%s=%s\n", key, enc_val > tmp + close(tmp) + # Copy the completed temp file back onto the original instead of + # renaming it: a rename replaces the inode, which would lose the + # file's permissions (a 0600 config holding secrets would come back + # umask-world-readable), turn a symlinked config into a regular file, + # and fail with EBUSY on a config bind-mounted as a single file — the + # mounted case this path exists for. The copy keeps the inode, mode, + # symlink and mount point. + # + # The copy itself is not atomic and the shell's `>` truncates the + # destination before cat writes a byte, so an ENOSPC or I/O error + # mid-copy used to leave a truncated config on disk — a truncated + # rest-server.properties loses `auth.authenticator` and boots the + # server with authentication off. Snapshot the original first, into a + # second exclusively created 0600 file for the same reason as the temp, + # and put it back when the copy fails. + bak = make_temp(file, "bak") + cmd = "cp -- " shquote(file) " " shquote(bak) + if (system(cmd) != 0) + die("cannot back up " file " before the copy-back") + cmd = "cat -- " shquote(tmp) " > " shquote(file) + if (system(cmd) != 0) { + # Best effort: the destination is already damaged, so restoring it + # from the snapshot comes first, and the temp file is kept for an + # operator who wants to inspect what was being written. + msg = "cannot copy " tmp " over " file + cmd = "cat -- " shquote(bak) " > " shquote(file) + if (system(cmd) == 0) die(msg "; the previous content is restored") + die(msg "; " file " is damaged, previous content is in " bak) + } + if (system("rm -f -- " shquote(tmp) " " shquote(bak)) != 0) + die("cannot remove " tmp " and " bak " after the copy-back") +} + +function props_get(file, key, decoded, b) { + props_load(file) + for (b = 1; b <= NBLOCK; b++) { + if (BTYPE[b] == "entry" && BKEY[b] == key) { + if (decoded) print unescape(BVAL[b]) + else print BVAL[b] + return + } + } + # Absence prints nothing and is NOT an exit status: callers assign from + # command substitution (`rest=$(get_prop ...)`) under a shell with errexit + # on, where a nonzero status would abort the entrypoint over a merely + # missing property. PROPS_MODE=has is the mode that reports by status. +} + +# Exit status only: 0 when the key has any definition at all, including an +# empty one. Guards that append a default must not treat `auth.authenticator=` +# as absent, because appending a second definition leaves the empty first one +# in force under first-definition-wins. +function props_has(file, key, b) { Review Comment: Answering here: my `9ae26c8` reply landed on the exit-code thread instead. All three are gone at head `0be7fde` — `props.awk` dispatches only `get`/`set` (line 435 dies otherwise), `enable-auth.sh` has no `props_has`, and `test-docker-entrypoint.sh` has no `PROPS_MODE=has`. Those four assertions became three `get` status checks. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. 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