From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (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 A729C1B07A3 for ; Thu, 26 Sep 2024 23:36:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727393804; cv=none; b=LvvRRAOJM0EyWmIWbI4E7mNx35nJYzcu4Nc5K08ZXvqmo/ycIZkTCsw6I/rmt4QtFOo/l6JVj1OAZms7oBzO6Hlw86MeCk8QnhV5xD/Cmmv2XmAbz+XYLDSoKWDT40JZV4sLQb8tdKSfP/Fl3PLg+QM4q4oJiit/ZsQY+24Q4bY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727393804; c=relaxed/simple; bh=auRMKL1VHLPn5sEdsai0MKgq314tffwblT0/P66foLE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=bfm2PQlDvEZAC6xax6kOeSaRwcf3aSOIwKyALFDhf2b/iWuk5yocLWS60XuM5cLNHoWuDjgRye107ED60+MCcbH1Cc6qaMdDjDPgdzCS/7zcZ1Xlm/cKBCItja9uBLMkD0sgHY13DK7zYbMKeyW1XXnOI4WNb15EsmW48H77zFY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--cmllamas.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=UjKmqrtv; arc=none smtp.client-ip=209.85.215.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--cmllamas.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="UjKmqrtv" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-7db6dbaca2cso1644997a12.0 for ; Thu, 26 Sep 2024 16:36:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1727393802; x=1727998602; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=T6NRiF2jzOTlmTLkf7ByKoCRNQ6oQZl+i/6FjfYR9L0=; b=UjKmqrtvihgYWXBhNwq111kAy1lP8WUSQ71t+KAnIgi4qxRdKLRwvEHv9rprckR4bl fJRNTh80+bmh+IzJxX8jwrPwSNJC77XmYRiUZuXNpk36Xa9TCPKm7A63GusK6dhAeO+L 4sb6gGSZUIDlVAPYqaMGflARZUKQSR1xHjwhdOtHRAn7h0XQlTZ4JxlyvJIQZOr8eZCc mhpbkIYa7WMS0JJZxLqbz/Rd+gdPOfj/2sCcTM6I9YzHWZ3CjGZCIn5yTBcI7zfr2t2C aYkoKCx9LYlPUf3hZP9D6jtq75eINW2Ycujkc6GXFAZsy9w+y5fZonRxOjNrcUEmjmbU GA0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727393802; x=1727998602; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=T6NRiF2jzOTlmTLkf7ByKoCRNQ6oQZl+i/6FjfYR9L0=; b=HmrhceJB940BHPLW8a8s2/l+s7LOrumLLSswWB+0zHe7OBXSQjndzS4HWgfU34BL9P HBDgL3+EL4BHhEVPcDSJyq2ZIXo/cgD5JsFdMLmTMtYaJrmmWjXerCn0jiV66kVb5OHG rxQDEoyPn1GYDDg8BCNG1M2xm3IDsxwLNbJsWXinR4hKQBgrPhD/KpP36pO8ExXO32Yq RiKwGGKQxA4HHjovdLddGBMMRRQydKdKqoH1hERzDxx/aldKtISIhRGEwZt3EuX9UEJ9 ZTjdsgiWGFC4B9KmZSCugpEFgx4fF4haQ4JR+3oiQP8OOkhVI2eEtYduDr3vZjgVWX9p 2ksg== X-Forwarded-Encrypted: i=1; AJvYcCX6OID+RCdN6P782LU1RgkNN3TRGBHilgC71KDex9q7Iqiry9qBftLERS403guMHqcHI5C5vlY=@vger.kernel.org X-Gm-Message-State: AOJu0YyYL9jbD5Rb+S7BizJ/Wm9bg4gf0Ud0GLVLqE77xsgeR8j14qhk MfmTNqTH8Y+6UQ4eLQjeZrJM5LzoXBUSR+40m4VgssPLWrGzDucKsytOffDB91I7jpnYmQfnp0L UvdvPcBWGWg== X-Google-Smtp-Source: AGHT+IFihG4ru2+qA62xmp+Q9HYnVhUZSB5tUQoaGcqfi/yvOJNOAZkdrn4uF1RoIXFBnpcn8PoMYI7uHJeYrg== X-Received: from xllamas.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5070]) (user=cmllamas job=sendgmr) by 2002:a17:90a:c211:b0:2d8:b6bc:e5fa with SMTP id 98e67ed59e1d1-2e0b8ed126bmr6261a91.3.1727393801170; Thu, 26 Sep 2024 16:36:41 -0700 (PDT) Date: Thu, 26 Sep 2024 23:36:12 +0000 In-Reply-To: <20240926233632.821189-1-cmllamas@google.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240926233632.821189-1-cmllamas@google.com> X-Mailer: git-send-email 2.46.1.824.gd892dcdcdd-goog Message-ID: <20240926233632.821189-2-cmllamas@google.com> Subject: [PATCH v2 1/8] binder: fix node UAF in binder_add_freeze_work() From: Carlos Llamas To: Greg Kroah-Hartman , "=?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?=" , Todd Kjos , Martijn Coenen , Joel Fernandes , Christian Brauner , Carlos Llamas , Suren Baghdasaryan , Yu-Ting Tseng Cc: linux-kernel@vger.kernel.org, kernel-team@android.com, Alice Ryhl , stable@vger.kernel.org, Todd Kjos Content-Type: text/plain; charset="UTF-8" In binder_add_freeze_work() we iterate over the proc->nodes with the proc->inner_lock held. However, this lock is temporarily dropped in order to acquire the node->lock first (lock nesting order). This can race with binder_node_release() and trigger a use-after-free: ================================================================== BUG: KASAN: slab-use-after-free in _raw_spin_lock+0xe4/0x19c Write of size 4 at addr ffff53c04c29dd04 by task freeze/640 CPU: 5 UID: 0 PID: 640 Comm: freeze Not tainted 6.11.0-07343-ga727812a8d45 #17 Hardware name: linux,dummy-virt (DT) Call trace: _raw_spin_lock+0xe4/0x19c binder_add_freeze_work+0x148/0x478 binder_ioctl+0x1e70/0x25ac __arm64_sys_ioctl+0x124/0x190 Allocated by task 637: __kmalloc_cache_noprof+0x12c/0x27c binder_new_node+0x50/0x700 binder_transaction+0x35ac/0x6f74 binder_thread_write+0xfb8/0x42a0 binder_ioctl+0x18f0/0x25ac __arm64_sys_ioctl+0x124/0x190 Freed by task 637: kfree+0xf0/0x330 binder_thread_read+0x1e88/0x3a68 binder_ioctl+0x16d8/0x25ac __arm64_sys_ioctl+0x124/0x190 ================================================================== Fix the race by taking a temporary reference on the node before releasing the proc->inner lock. This ensures the node remains alive while in use. Fixes: d579b04a52a1 ("binder: frozen notification") Cc: stable@vger.kernel.org Reviewed-by: Alice Ryhl Acked-by: Todd Kjos Signed-off-by: Carlos Llamas --- drivers/android/binder.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 978740537a1a..4d90203ea048 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -5552,6 +5552,7 @@ static bool binder_txns_pending_ilocked(struct binder_proc *proc) static void binder_add_freeze_work(struct binder_proc *proc, bool is_frozen) { + struct binder_node *prev = NULL; struct rb_node *n; struct binder_ref *ref; @@ -5560,7 +5561,10 @@ static void binder_add_freeze_work(struct binder_proc *proc, bool is_frozen) struct binder_node *node; node = rb_entry(n, struct binder_node, rb_node); + binder_inc_node_tmpref_ilocked(node); binder_inner_proc_unlock(proc); + if (prev) + binder_put_node(prev); binder_node_lock(node); hlist_for_each_entry(ref, &node->refs, node_entry) { /* @@ -5586,10 +5590,13 @@ static void binder_add_freeze_work(struct binder_proc *proc, bool is_frozen) } binder_inner_proc_unlock(ref->proc); } + prev = node; binder_node_unlock(node); binder_inner_proc_lock(proc); } binder_inner_proc_unlock(proc); + if (prev) + binder_put_node(prev); } static int binder_ioctl_freeze(struct binder_freeze_info *info, -- 2.46.1.824.gd892dcdcdd-goog