From 65dbe2766a5a2256f9adf96b67930e404d4ad28f Mon Sep 17 00:00:00 2001
From: Valentin Lab <valentin.lab@kalysto.org>
Date: Mon, 3 May 2021 18:09:35 +0200
Subject: [PATCH] new: [rsync-backup-target] accept restore commands

Signed-off-by: Valentin Lab <valentin.lab@kalysto.org>
---
 .../build/src/usr/local/sbin/ssh-cmd-validate | 29 ++++++++++++++++---
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/rsync-backup-target/build/src/usr/local/sbin/ssh-cmd-validate b/rsync-backup-target/build/src/usr/local/sbin/ssh-cmd-validate
index 415f8b56..7c3dc865 100755
--- a/rsync-backup-target/build/src/usr/local/sbin/ssh-cmd-validate
+++ b/rsync-backup-target/build/src/usr/local/sbin/ssh-cmd-validate
@@ -28,6 +28,7 @@ if [ -z "$1" ] || ! [[ "$1" =~ ^[a-zA-Z0-9._-]+$ ]]; then
 fi
 
 ident="$1"
+log "IDENTIFIED AS $ident"
 
 reject() {
     log "REJECTED: $SSH_ORIGINAL_COMMAND"
@@ -43,20 +44,40 @@ if [[ "$SSH_ORIGINAL_COMMAND" =~ [\&\(\{\;\<\>\`\$\}] ]]; then
     reject
 fi
 
-if [[ "$SSH_ORIGINAL_COMMAND" =~ ^"rsync --server -"[vloHgDtpArRzCeiLsfx\.]+(" --"[a-z=%-]+|" --partial-dir .rsync-partial")*" . /var/mirror/$ident"$ ]]; then
-	log "ACCEPTED: $SSH_ORIGINAL_COMMAND"
+if [[ "$SSH_ORIGINAL_COMMAND" =~ ^"rsync --server -"[vnloHgDtpArRzCeiLsfx\.]+(" --"[a-z=%-]+|" --partial-dir .rsync-partial")*" . /var/mirror/$ident"$ ]]; then
+	log "ACCEPTED BACKUP COMMAND: $SSH_ORIGINAL_COMMAND"
 
     ## Interpret \ to allow passing spaces (want to avoid possible issue with \n)
     #read -a ssh_args <<< "${SSH_ORIGINAL_COMMAND}"
     ssh_args=(${SSH_ORIGINAL_COMMAND})
 
-    # echo "Would accept: $SSH_ORIGINAL_COMMAND" >&2
 	exec sudo "${ssh_args[@]::3}" \
          "--log-file=/var/log/rsync/target_$1_rsync.log" \
          "--log-file-format=%i %o %f %l %b" \
          "${ssh_args[@]:3}"
+elif [[ "$SSH_ORIGINAL_COMMAND" =~ ^"rsync --server --sender -"[vnloHgDtpArRzCeiLsfx\.]+(" --"[a-z=%-]+|" --partial-dir .rsync-partial")*" . /var/mirror/$ident"(|/.*)$ ]]; then
+
+    ## Interpret \ to allow passing spaces (want to avoid possible issue with \n)
+    #read -a ssh_args <<< "${SSH_ORIGINAL_COMMAND}"
+    ssh_args=(${SSH_ORIGINAL_COMMAND})
+
+    last_arg="${ssh_args[@]: -1:1}"
+    if ! new_path=$(realpath "$last_arg" 2>/dev/null); then
+        log "FINAL PATH INVALID"
+        reject
+    fi
+
+    if [[ "$new_path" != "$last_arg" ]] &&
+           [[ "$new_path" != "/var/mirror/$ident/"* ]] &&
+           [[ "$new_path" != "/var/mirror/$ident" ]]; then
+        log "FINAL PATH SUSPICIOUS"
+        reject
+    fi
+
+	log "ACCEPTED RECOVER COMMAND: $SSH_ORIGINAL_COMMAND"
+	exec sudo "${ssh_args[@]}"
 else
-    log "NO MATCH ACCEPTED COMMAND"
+    log "REFUSED COMMAND AS IT DOESN'T MATCH ANY EXPECTED COMMAND"
 	reject
 fi