Merge branch 'master' of plutz.net:cgilite

[cgilite] / session.sh

diff --git a/session.sh b/session.sh
new file mode 100755 (executable)
index 0000000..25a6598
--- /dev/null
+++ b/session.sh
@@ -0,0 +1,72 @@
+#!/bin/sh
+
+[ -n "$include_session" ] && return 0
+include_session="$0"
+
+server_key(){
+  IDFILE="${IDFILE:-${_DATA:-.}/serverkey}"
+  if [ "$(stat -c %s "$IDFILE")" -ne 512 ] || ! cat "$IDFILE"; then
+    dd count=1 bs=512 if=/dev/urandom \
+    | tee "$IDFILE"
+  fi 2>&-
+}
+
+slopecode(){
+  # 6-Bit Code that retains sort order of input data, while beeing safe to use
+  # in ascii transmissions, unix file names, HTTP URLs, and HTML attributes
+
+  uuencode -m - | sed '
+    1d;$d; 
+    y;ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/;0123456789:=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz;
+  '
+}
+
+randomid(){
+  dd bs=12 count=1 if=/dev/urandom 2>&- \
+  | slopecode
+}
+
+timeid(){
+  d=$(($(date +%s) % 4294967296))
+  { printf "$(
+      printf \\%o \
+        $((d / 16777216 % 256)) \
+        $((d / 65536 % 256)) \
+        $((d / 256 % 256)) \
+        $((d % 256))
+    )"
+    dd bs=8 count=1 if=/dev/urandom 2>&-
+  } | slopecode
+}
+
+checkid(){ grep -m 1 -xE '[0-9a-zA-Z:=]{16}'; }
+
+update_session(){
+  local session sid time sig serverkey checksig
+
+  IFS=- read -r sid time sig <<-END
+       $(COOKIE session)
+       END
+  serverkey="$(server_key)"
+  
+  checksig="$(printf %s "$sid" "$time" "$serverkey" | sha256sum)"
+  checksig="${checksig%% *}"
+  d=$(date +%s)
+  
+  if [ "$checksig" != "$sig" \
+    -o "$time" -lt "$d" \
+    -o ! "$(printf %s "$sid" |checkid)" ] 2>&-
+  then
+    debug Setting up new session
+    sid="$(randomid)"
+  fi
+
+  time=$(( $(date +%s) + 7200 ))
+  sig="$(printf %s "$sid" "$time" "$serverkey" |sha256sum)"
+  sig="${sig%% *}"
+  printf %s\\n "${sid}-${time}-${sig}"
+}
+
+SESSION_ID="$(update_session)"
+SET_COOKIE 0 session="$SESSION_ID" Path=/ SameSite=Strict HttpOnly
+SESSION_ID="${SESSION_ID%%-*}"