fix(sandbox): recognize Bash line-number exec denials

packages/sandbox/src/violation.ts

@@ -42,7 +42,7 @@ const SPAWN_EXEC_PATH = /spawn(?:Sync)?\s+(\/\S+)\s+(?:EPERM|EACCES)/;
 // "/bin/sh: <lineno>: <path>: Permission denied" (lineno optional across shells). Two
 // linear tests (detect + extract), mirroring the SH_EXEC split, to stay ReDoS-safe.
 const LINUX_EXEC_PERM = /[Pp]ermission denied/;
-const LINUX_EXEC_PATH = /(?:^|[/\s])(?:sh|bash|dash|zsh): (?:\d+: )?(\/[^:\n]+):/;
+const LINUX_EXEC_PATH = /(?:^|[/\s])(?:sh|bash|dash|zsh): (?:(?:line )?\d+: )?(\/[^:\n]+):/;
 
 function firstMatchingLine(stderr: string, re: RegExp): string | null {
   for (const line of stderr.split(/\r?\n/)) if (re.test(line)) return line.trim();

packages/sandbox/test/violation.test.ts

@@ -265,6 +265,16 @@ const LL_DS = {
 const failLL = (stderr: string) => ({ exitCode: 126, stdout: "", stderr });
 
 describe("classifyViolation — Linux Landlock floor mode (Phase 2)", () => {
+  test("Bash line-number denials identify masked processes and keep allowed exec failures ambient", () => {
+    for (const denySet of [LINUX_DS, LL_DS]) {
+      const denied = classifyViolation(failLL("/bin/sh: line 1: /usr/bin/curl: Permission denied"), denySet);
+      assert.equal(denied?.kind, "process");
+      assert.equal(denied?.confidence, "confirmed");
+      assert.equal(denied?.target, "/usr/bin/curl");
+      assert.equal(classifyViolation(failLL("/bin/sh: line 1: /usr/bin/make: Permission denied"), denySet), null);
+    }
+  });
+
   test("a floor-OUTSIDE exec denial (dropped /tmp binary) is confirmed exec-floor-deny", () => {
     const v = classifyViolation(failLL("/bin/sh: 1: /tmp/spikestash/payload: Permission denied"), LL_DS);
     assert.equal(v?.kind, "process");