X-Git-Url: https://git.plutz.net/?a=blobdiff_plain;f=session.sh;h=5b36ae032af4e818af91d4b73190a9f83614da15;hb=a76f6a5931782adbae717678f8f92569ed0d5bcb;hp=b52ac0a5cc6fab71ba8a7926c27ac692a5c867de;hpb=47a1cf6b49b7c063f1ac3f5e3b401c71de45230e;p=cgilite

diff --git a/session.sh b/session.sh
index b52ac0a..5b36ae0 100755
--- a/session.sh
+++ b/session.sh
@@ -6,6 +6,28 @@ include_session="$0"
 _DATE="$(date +%s)"
 SESSION_TIMEOUT="${SESSION_TIMEOUT:-7200}"
 
+if ! which uuencode >/dev/null; then
+  uuencode() { busybox uuencode "$@"; }
+fi
+if ! which sha256sum >/dev/null; then
+  sha256sum() { busybox sha256sum "$@"; }
+fi
+
+if which openssl >/dev/null; then
+  session_mac(){ { [ $# -gt 0 ] && printf %s "$*" || cat; } | openssl dgst -sha1 -hmac "$(server_key)" -binary |slopecode; }
+else
+  # Gonzo MAC if openssl is unavailable
+  session_mac(){
+    { server_key | dd status=none bs=256 count=1 skip=1
+      { server_key | dd status=none bs=256 count=1
+        [ $# -gt 0 ] && printf %s "$*" || cat
+      } \
+      | sha256sum -;
+    } \
+    | sha256sum | cut -d\  -f1
+  }
+fi
+
 server_key(){
   IDFILE="${IDFILE:-${_DATA:-.}/serverkey}"
   if [ "$(stat -c %s "$IDFILE")" -ne 512 ] || ! cat "$IDFILE"; then
@@ -18,23 +40,13 @@ 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 '
+  { [ $# -gt 0 ] && printf %s "$*" || cat; } \
+  | uuencode -m - | sed '
     1d;$d; 
     y;ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/;0123456789:=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz;
   '
 }
 
-session_mac(){
-  local info
-  [ $# -eq 0 ] && info="$(cat)" || info="$*"
-
-  if which openssl >/dev/null; then
-    printf %s "$info" |openssl dgst -sha1 -hmac "$(server_key)" -binary |slopecode
-  else
-    { printf %s "$info"; server_key; } |sha256sum |cut -d\  -f1
-  fi
-}
-
 randomid(){
   dd bs=12 count=1 if=/dev/urandom 2>&- \
   | slopecode
@@ -53,14 +65,14 @@ timeid(){
   } | slopecode
 }
 
-checkid(){ grep -m 1 -xE '[0-9a-zA-Z:=]{16}'; }
-
 transid(){
   # transaction ID to modify a given file
   local file="$1"
   session_mac "$(stat -c %F%i%n%N%s%Y "$file" 2>&-)" "$SESSION_ID"
 }
 
+checkid(){ { [ $# -gt 0 ] && printf %s "$*" || cat; } | grep -m 1 -xE '[0-9a-zA-Z:=]{16}'; }
+
 update_session(){
   local session sid time sig checksig
 
@@ -83,18 +95,16 @@ update_session(){
   printf %s\\n "${sid} ${time} ${sig}"
 }
 
-SESSION_KEY="$(update_session)"
-SET_COOKIE 0 session="$SESSION_KEY" Path=/ SameSite=Strict HttpOnly
-SESSION_ID="${SESSION_KEY%% *}"
-
 SESSION_BIND() {
+  # Set tamper-proof authenticated cookie
   local key="$1" value="$2"
   SET_COOKIE session "$key"="${value} $(session_mac "$value" "$SESSION_ID")"
 }
 
 SESSION_VAR() {
-  local key="$1"
-  local value sig
+  # read authenticated cookie
+  # fail if value has been tampered with
+  local key="$1" value sig
   value="$(COOKIE "$key")"
   sig="${value##* }" value="${value% *}"
   if [ "$sig" = "$(session_mac "$value" "$SESSION_ID")" ]; then
@@ -103,3 +113,12 @@ SESSION_VAR() {
     return 1
   fi
 }
+
+SESSION_COOKIE() {
+  SET_COOKIE 0 session="$SESSION_KEY" Path=/ SameSite=Strict HttpOnly
+}
+
+SESSION_KEY="$(update_session)"
+SESSION_ID="${SESSION_KEY%% *}"
+
+[ "$1" = nocookie ] || SESSION_COOKIE