From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D29412E2EFF; Tue, 15 Jul 2025 13:35:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752586528; cv=none; b=M84LhdQApjfJtmTKnxjXAIqZg/MiRaybpl713ktPtM3vhWZBJao9zYQWCAYfeNdkcJw2e8Ea7/uOwtjX8zoEy54BTQuGFTdey5fP2qETYBcJaPaY3nNtP4x+GKMujrwuC5P7PeELoVr92QVJE559NFrGaR1GpQispaH+8qls+5g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752586528; c=relaxed/simple; bh=FFBOhoB+oQLuP9QaYuSpt2PpAR+Ld1yZ5Oz/69BH89s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZGs+V+ko+oymKCZEoyPq3UKeZWZ8/rwtkWCL8zsWp36kBgVJlhhIMUd7ZeX7RsMzi6Qvac7lu9wpmz+O0Y0foTrpLD87jlzreF1fdVEIsMIKiTzScTrWrnDpta1wYqcBKfVhnIxqZvHSPmufHDAjUc/pe2V0EKZgSt9jhnDbQnI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hojrtj19; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hojrtj19" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66535C4CEF6; Tue, 15 Jul 2025 13:35:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1752586528; bh=FFBOhoB+oQLuP9QaYuSpt2PpAR+Ld1yZ5Oz/69BH89s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hojrtj19o+N4a/izBR76Pi4sia+umTzeZp/BBrGw9KN3/q3kKZqC9sAer/IA3TOXS h4p+k1+NuG7Inxfz4oeuSM7KJCXL0aPIXvZ+yUSWtVFGiISjQFq0gBM9oBq7zX4Cvm oTZ6EKYA8oz8fzPl9sdst0rRJxk6sH/oMrudAc64= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+e04e2c007ba2c80476cb@syzkaller.appspotmail.com, Kohei Enju , Simon Horman , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.4 098/148] rose: fix dangling neighbour pointers in rose_rt_device_down() Date: Tue, 15 Jul 2025 15:13:40 +0200 Message-ID: <20250715130804.241130667@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250715130800.293690950@linuxfoundation.org> References: <20250715130800.293690950@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kohei Enju [ Upstream commit 34a500caf48c47d5171f4aa1f237da39b07c6157 ] There are two bugs in rose_rt_device_down() that can cause use-after-free: 1. The loop bound `t->count` is modified within the loop, which can cause the loop to terminate early and miss some entries. 2. When removing an entry from the neighbour array, the subsequent entries are moved up to fill the gap, but the loop index `i` is still incremented, causing the next entry to be skipped. For example, if a node has three neighbours (A, A, B) with count=3 and A is being removed, the second A is not checked. i=0: (A, A, B) -> (A, B) with count=2 ^ checked i=1: (A, B) -> (A, B) with count=2 ^ checked (B, not A!) i=2: (doesn't occur because i < count is false) This leaves the second A in the array with count=2, but the rose_neigh structure has been freed. Code that accesses these entries assumes that the first `count` entries are valid pointers, causing a use-after-free when it accesses the dangling pointer. Fix both issues by iterating over the array in reverse order with a fixed loop bound. This ensures that all entries are examined and that the removal of an entry doesn't affect subsequent iterations. Reported-by: syzbot+e04e2c007ba2c80476cb@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=e04e2c007ba2c80476cb Tested-by: syzbot+e04e2c007ba2c80476cb@syzkaller.appspotmail.com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kohei Enju Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250629030833.6680-1-enjuk@amazon.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/rose/rose_route.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) diff --git a/net/rose/rose_route.c b/net/rose/rose_route.c index 49a0e7d5a7684..91855d11ad15d 100644 --- a/net/rose/rose_route.c +++ b/net/rose/rose_route.c @@ -497,22 +497,15 @@ void rose_rt_device_down(struct net_device *dev) t = rose_node; rose_node = rose_node->next; - for (i = 0; i < t->count; i++) { + for (i = t->count - 1; i >= 0; i--) { if (t->neighbour[i] != s) continue; t->count--; - switch (i) { - case 0: - t->neighbour[0] = t->neighbour[1]; - /* fall through */ - case 1: - t->neighbour[1] = t->neighbour[2]; - break; - case 2: - break; - } + memmove(&t->neighbour[i], &t->neighbour[i + 1], + sizeof(t->neighbour[0]) * + (t->count - i)); } if (t->count <= 0) -- 2.39.5