From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f47.google.com (mail-dl1-f47.google.com [74.125.82.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2ECD478F4F for ; Sat, 11 Apr 2026 20:08:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775938141; cv=none; b=aqjzdI+5s8xBh8idoGeEZUVzNjnwkdRBMmmFFIvutBO1urP0AOAlGzbVnlmSaNl8SW7htUxfjt1kTWfwFl4Bh/lb6izQHyVB0RiWWl8nm7v5oAkczqVnoeAJnVPlAxClaQJHtJD3Qa0vV6kFd1+cA0+QF92UumZfqUP5PJ9hPec= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775938141; c=relaxed/simple; bh=8xhVsNEovXBIqkd8ZyL4/mEXPIUZR9D+ivZVkO1UW68=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=smu/YaQtCKjhHdCkw5bb8go+VUCHqeVjsnrAbVc2+hkaXywvuQlLf+ewjMlVRXke2hSFBkERvKWiWrTFC0WSeEgpq9SQ198RBWb4iYd9ZB3KNEKnoFOf21/g3dVspsznVbnMkhn53Zj6vsmNvPrCNYZN8EqkePMjLuTZXZyIcAg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=C/Eue6Ql; arc=none smtp.client-ip=74.125.82.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="C/Eue6Ql" Received: by mail-dl1-f47.google.com with SMTP id a92af1059eb24-12732165d1eso12774217c88.1 for ; Sat, 11 Apr 2026 13:08:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1775938139; x=1776542939; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=zel3kbV3nN+yCvqWZ9R+6Oy31tKSfaLXtfM04C0iSeM=; b=C/Eue6Ql9GIux804mvPyZ8bGM9Y/4gN2p0G7CzUscA5KgfG0PM61/1ywnEtOPLBgXX 8SthdvxqI0ac0gBmH3lwMMw8VQHtvx2z4+koSZzsUr4WUd7jn6DV75Z4yKGepPZyoAQv cKorPLnPKhXGektGvihvCnaMBceXcIfnrFzPezh2RIDEuIpQYcvyGzzuBrHjwHKdNA/I vSkx3N0K/kuNxS1cMKpXTqmiutZfOJN/5NitmYVLaELML1Yl7AEFEwoOlOR1bGFlbNFE +ZZxCfUfW07HkdJAzgH+vMGR5DWCugWOubBM2UiKJHe5d7KuZb7g7zJG4FsnGURNfZs7 WHIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775938139; x=1776542939; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=zel3kbV3nN+yCvqWZ9R+6Oy31tKSfaLXtfM04C0iSeM=; b=exGzWitsJYwoCzs4GCVpoFu51zOPdm45LZroLvYiDo1dhO+fe5WXa6Cjm0GdpHBsvh zJwGKtrJGlgCURBZhUFZukZSpSKQ7KYcC8CAZW8j/xf8aBdDiwaGs0qoY0ABe8SjnEfK 3DR8ivmlALph4YS9AtzvrjepynC8WwiOfrgf8It6NO6ZYzTGQ4jBTYKeld4UpATJ4CzU TrvPDHyRNyaOOwN3X7Xc8mJT5CcqE7EKjx7raumLTZSfcjjlwHYmRfrlCrSPtBEjJL8d qthtEmF7hFmzpjYPnuCSq6M+g+1d7UCcEbya2+WEiJGbHgF5NUtMf5rExccklS0qeTd0 z6YQ== X-Forwarded-Encrypted: i=1; AJvYcCXhSHfH8NJ4wVY3luQu0cn+328byKVuantMax09i9xuSRTHTRUqzihMtQNnaVT+IA4PFho=@vger.kernel.org X-Gm-Message-State: AOJu0YxjreO6xcMIcez2RspBF8IDHLuwfaSWOiwnvROyygEyDOqnxB18 cD5Wfgp7qkey3gBDBInCE4STn009Rv2JDwbndGm2JheA+/x1q7ErrTmM X-Gm-Gg: AeBDievqVeJTzU91IWcsHo3o4DxB26/DaungOoUVWPRX7gMDcf97BkTotlzKcEB65L6 1IoU/YvkYGKo6wqlMIeHSM5ryvR0OJ+t9UR9E612lMSBwPq9zQ0tZpB7DZJgXkXEHFRcWHGJp2D qtvAJkevD8xgxa3IKwzNpWhjfPMlMNqxVqG4Kmu15h/jKaYsw3F8vsnA3usLzkOGHrCn71TsYRW M1wi5KpB47c0347XPm1TQZ8l6cYrf3ULWrMauvyRWVtYlKkGN9pfXrPHrcPyJpNTTnCqW06/bC0 Iucq76w463bxRZEOWlOfH6lb8/aZ4AwgvUzUI3Xj1kgujoUDk3XQsGVkDslPimNVBjoovgY9xA+ d332skUTnJdgEJiIfTtI2EGK9QGUkAc4JV1x2zpw8sa6K/2S7UKGXHyfbQAyOXzGIjXVMQZnd2f 4x+FnsMtFhBYTPurvb43SKGnDrIGf6j6he6HfMxtaQxRO2wYtizDHTf6qCykt1icQnuAFIX6cNi +h4RmxcYuVA2wp8xrDw X-Received: by 2002:a05:7022:6183:b0:11d:c22e:a131 with SMTP id a92af1059eb24-12c34e37b04mr4480315c88.3.1775938139070; Sat, 11 Apr 2026 13:08:59 -0700 (PDT) Received: from efaec68ba852.tailc0aff1.ts.net ([206.206.192.132]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-12c3459f7ffsm8078325c88.3.2026.04.11.13.08.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 11 Apr 2026 13:08:58 -0700 (PDT) From: Weiming Shi To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Barret Rhoden , Emil Tsalapatis , bpf@vger.kernel.org, Xiang Mei , Weiming Shi Subject: [PATCH bpf v3 0/2] bpf: Fix arena VMA use-after-free on fork Date: Sat, 11 Apr 2026 13:08:39 -0700 Message-ID: <20260411200840.1793567-2-bestswngs@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit arena_vm_open() only increments a refcount on the shared vma_list entry but never registers the new VMA. After fork + parent munmap, vml->vma becomes a dangling pointer. bpf_arena_free_pages -> zap_pages then dereferences it, causing a slab-use-after-free in zap_page_range_single. Patch 1 fixes the bug by tracking each child VMA separately in arena_vm_open, and adds arena_vm_may_split() to prevent VMA splitting. Patch 2 adds a selftest that reproduces the issue (requires KASAN to detect the UAF). v3: - Added arena_vm_may_split() to prevent VMA splitting - Reuse remember_vma() in arena_vm_open(), removed HugeTLB references - selftests: fixed copyright, trimmed comments, use sysconf() v2: - Added missing Reported-by tag Weiming Shi (2): bpf: Fix use-after-free of arena VMA on fork selftests/bpf: Add test for arena VMA use-after-free on fork kernel/bpf/arena.c | 23 ++++-- .../selftests/bpf/prog_tests/arena_fork.c | 80 +++++++++++++++++++ .../testing/selftests/bpf/progs/arena_fork.c | 41 ++++++++++ 3 files changed, 138 insertions(+), 6 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/arena_fork.c create mode 100644 tools/testing/selftests/bpf/progs/arena_fork.c -- 2.43.0