From 40a65d5f3a5590dfc6ec78b700d52dd1487dcfcb Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Sun, 8 Nov 2026 06:54:22 +0000
Subject: [PATCH] fix(agent): prevent exact token match bypass in workdir
 command validation

Previously, `validate_command` only checked if a padded token (e.g., `rm `)
was in the joined command string. This allowed malicious payloads like `npm run rm`
where the exact token had no trailing space to bypass the check.

This commit adds a loop to iterate through every parsed token and verifies exact
matches against sensitive binaries ("rm", "sudo", "chmod", "chown", "curl", "wget", "ssh", "scp").

Co-authored-by: bobdivx <6737167+bobdivx@users.noreply.github.com>
---
 .jules/sentinel.md                    |  4 ++++
 crates/agent/src/tools/workdir_cmd.rs | 15 +++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/.jules/sentinel.md b/.jules/sentinel.md
index 1a9528255..ade312db4 100644
--- a/.jules/sentinel.md
+++ b/.jules/sentinel.md
@@ -17,3 +17,7 @@
 **Vulnerability:** The `verify_github_sig` function in `apps/server/src/infra_routes.rs` verified GitHub webhook signatures using standard string comparison `expected.eq_ignore_ascii_case(hex_sig)`.
 **Learning:** String comparison functions exit early as soon as a character mismatch is found. In a cryptographic context, this variable response time leaks information and allows an attacker to perform a timing attack to forge a valid HMAC signature by guessing it byte by byte.
 **Prevention:** Always use a constant-time comparison library (like `hmac`'s `verify_slice()`) to compare cryptographic hashes, secrets, and signatures to prevent side-channel timing attacks. Avoid custom implementations of standard cryptographic algorithms.
+## 2024-05-18 - Exact Token Matching in Command Validation
+**Vulnerability:** Command validation in `workdir_cmd.rs` relied on joined strings for multi-word blocked phrases (e.g., `rm `), which allowed an attacker to bypass it by placing the sensitive token at the end of the command string (e.g., `npm run rm`).
+**Learning:** Checking a joined string for an exact blocked token padding (like `rm `) is insufficient as it fails to catch exact matches that appear as the last argument where no trailing space exists. Relying solely on tokenized matches also breaks multi-word blocked phrases. Both checks must be implemented simultaneously for robustness.
+**Prevention:** Always verify both the joined command string against multi-word blocked phrases AND individual tokenized arguments for exact matches of sensitive binaries.
diff --git a/crates/agent/src/tools/workdir_cmd.rs b/crates/agent/src/tools/workdir_cmd.rs
index 46a5ff54a..0b5c06144 100644
--- a/crates/agent/src/tools/workdir_cmd.rs
+++ b/crates/agent/src/tools/workdir_cmd.rs
@@ -112,6 +112,20 @@ fn validate_command(raw: &str) -> std::result::Result<Vec<String>, String> {
             return Err(format!("token interdit dans la commande : {bad}"));
         }
     }
+    for part in &parts {
+        let p_lower = part.to_ascii_lowercase();
+        if p_lower == "rm"
+            || p_lower == "sudo"
+            || p_lower == "chmod"
+            || p_lower == "chown"
+            || p_lower == "curl"
+            || p_lower == "wget"
+            || p_lower == "ssh"
+            || p_lower == "scp"
+        {
+            return Err(format!("token exact interdit dans la commande : {}", part));
+        }
+    }
     let bin = parts[0].as_str();
     let bin_base = Path::new(bin)
         .file_name()
@@ -354,6 +368,7 @@ mod tests {
     fn blocks_obfuscated_commands() {
         assert!(validate_command("npm run \"s\"udo").is_err());
         assert!(validate_command("cat \"..\"/\"..\"/etc/passwd").is_err());
+        assert!(validate_command("npm run rm").is_err());
     }
 }