From 2096410b2959132a1d495808a763dc8e1916da13 Mon Sep 17 00:00:00 2001
From: Hussein Kadhim <husseinkad.dev@gmail.com>
Date: Tue, 13 Oct 2026 19:44:27 +0300
Subject: [PATCH] fix(libkernel): report EPERM before EINVAL when writing
 kern.proc.pathname

FreeBSD sysctl_root rejects a write to a read-only node with EPERM before the node handler checks the MIB length, so a write with a short or long kern.proc.pathname MIB fails with EPERM. sysctlbyname for kern.proc.pathname now goes through sysctl with its 3-component MIB so it follows the same order.
---
 .../prx/libkernel/System/src/SystemConfiguration.cpp | 12 ++++++------
 core/libs/tests/GuestSystemConfiguration.cpp         |  4 ++++
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/core/libs/prx/libkernel/System/src/SystemConfiguration.cpp b/core/libs/prx/libkernel/System/src/SystemConfiguration.cpp
index 672c9d291..795a4d019 100644
--- a/core/libs/prx/libkernel/System/src/SystemConfiguration.cpp
+++ b/core/libs/prx/libkernel/System/src/SystemConfiguration.cpp
@@ -138,14 +138,14 @@ int APS5_VABI sysctl_nid_postfix(const int* name, std::uint32_t nameLength, void
         return CopyOut(&physmem, sizeof(physmem), oldValue, oldLength);
     }
     if (nameLength >= 3 && name[0] == 1 && name[1] == 14 && name[2] == 12) {
-        if (nameLength != 4) {
-            *__error_nid_postfix() = 22;
-            return -1;
-        }
         if (newValue != nullptr) {
             *__error_nid_postfix() = 1;
             return -1;
         }
+        if (nameLength != 4) {
+            *__error_nid_postfix() = 22;
+            return -1;
+        }
         const int pid = name[3];
         if (pid != -1 && pid != getpid_nid_postfix()) {
             *__error_nid_postfix() = 3;
@@ -184,8 +184,8 @@ int APS5_VABI sysctlbyname_nid_postfix(const char* name, void* oldValue, std::si
         return -1;
     }
     if (std::strcmp(name, "kern.proc.pathname") == 0) {
-        *__error_nid_postfix() = 22;
-        return -1;
+        static constexpr int mib[] = {1, 14, 12};
+        return sysctl_nid_postfix(mib, 3, oldValue, oldLength, newValue, newLength);
     }
     if (std::strcmp(name, "kern.arandom") == 0) {
         static constexpr int mib[] = {1, 37};
diff --git a/core/libs/tests/GuestSystemConfiguration.cpp b/core/libs/tests/GuestSystemConfiguration.cpp
index 1ad0f5c6f..b960fb85f 100644
--- a/core/libs/tests/GuestSystemConfiguration.cpp
+++ b/core/libs/tests/GuestSystemConfiguration.cpp
@@ -127,6 +127,10 @@ static void CheckPathnameSysctl() {
     const int mibTooLong[] = {1, 14, 12, -1, 0};
     Require(sysctl_nid_postfix(mibTooLong, 5, buffer, &length, nullptr, 0) == -1 && *__error_nid_postfix() == 22);
 
+    Require(sysctl_nid_postfix(mibTooShort, 3, buffer, &length, buffer, sizeof(buffer)) == -1 && *__error_nid_postfix() == 1);
+    Require(sysctl_nid_postfix(mibTooLong, 5, buffer, &length, buffer, sizeof(buffer)) == -1 && *__error_nid_postfix() == 1);
+    Require(sysctlbyname_nid_postfix("kern.proc.pathname", buffer, &length, buffer, sizeof(buffer)) == -1 && *__error_nid_postfix() == 1);
+
     const int mibSelf[] = {1, 14, 12, -1};
     length = 0;
     Require(sysctl_nid_postfix(mibSelf, 4, nullptr, &length, nullptr, 0) == 0 && length == sizeof("/app0/eboot.bin"));