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 8FE6B3D9DD3; Sat, 28 Feb 2026 17:40:45 +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=1772300445; cv=none; b=pL0/shjve4RbnSHZ7xDJ+GKHY4+/9aOJINsqJPQoDkhuY9HlFfZzTP7VVMbc9V1pz2E9Wj3MVKCiJ0XDQuKSPXK7xjQfkE9E/ckb/kdwfG2WLOJKt2iYIOGu9uk/LBAM4ycmz8pNnt7eVgroTz42mCHt5Csm/aw3O7AjRA90a1M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300445; c=relaxed/simple; bh=2jMmiVVMdvqj27SNqhkV2zWGqwRFbajKz7cQ3iAA9q4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=F5Eq6Q9XtLMVdGyVJci+UjAmUxkZ6YY5OzuNh1Nq6UOh9hPCo1CGC/GfVDE0j+zMO2whV2GVRsUVqO/yqMGYCKoEPZU9N9hVn35omxLJAth2/RYYvWkDwohNe8V1gIIpJGwUD1esFAAER4uWgYVwzv1AF/8nPZ2ariDg7qZoJys= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Zqh8Vh4K; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Zqh8Vh4K" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C32DAC19424; Sat, 28 Feb 2026 17:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772300445; bh=2jMmiVVMdvqj27SNqhkV2zWGqwRFbajKz7cQ3iAA9q4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Zqh8Vh4K5s9wP8S/Qhdsn8fA1/hTAdIcWg8qOse5ZCoUYnV9k2m4hv2opFdaSvoyd oy6ovxiX0T3gyW0ThOosg/1RYJMHCBJ0xBmMj1gjLB0ttTfTYm569i+5y4EsJOeb1b qtZpweR4MbEPw9Xgo0PNh5qiUnWiBik9GRZKQQCGqi7W/CwohhPjmGgXVqPvKy5qHx BC4taGmsJiTjg0wOyQuGCyJGJYNLwcyfznHkGIOmWrrMCVvZUTGQvObSALDbopjNQ2 qGAzj10ZA7HCZG+A6sDlqLL0O+Buu7JPWnTf9ChfN6aXp42aWpPE1jNkSz4A+r6EWj T+PMG2rTWQBJA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jakub Kicinski , Simon Horman , Paolo Abeni , Sasha Levin Subject: [PATCH 6.19 485/844] netconsole: avoid OOB reads, msg is not nul-terminated Date: Sat, 28 Feb 2026 12:26:38 -0500 Message-ID: <20260228173244.1509663-486-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228173244.1509663-1-sashal@kernel.org> References: <20260228173244.1509663-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Jakub Kicinski [ Upstream commit 82aec772fca2223bc5774bd9af486fd95766e578 ] msg passed to netconsole from the console subsystem is not guaranteed to be nul-terminated. Before recent commit 7eab73b18630 ("netconsole: convert to NBCON console infrastructure") the message would be placed in printk_shared_pbufs, a static global buffer, so KASAN had harder time catching OOB accesses. Now we see: printk: console [netcon_ext0] enabled BUG: KASAN: slab-out-of-bounds in string+0x1f7/0x240 Read of size 1 at addr ffff88813b6d4c00 by task pr/netcon_ext0/594 CPU: 65 UID: 0 PID: 594 Comm: pr/netcon_ext0 Not tainted 6.19.0-11754-g4246fd6547c9 Call Trace: kasan_report+0xe4/0x120 string+0x1f7/0x240 vsnprintf+0x655/0xba0 scnprintf+0xba/0x120 netconsole_write+0x3fe/0xa10 nbcon_emit_next_record+0x46e/0x860 nbcon_kthread_func+0x623/0x750 Allocated by task 1: nbcon_alloc+0x1ea/0x450 register_console+0x26b/0xe10 init_netconsole+0xbb0/0xda0 The buggy address belongs to the object at ffff88813b6d4000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 0 bytes to the right of allocated 3072-byte region [ffff88813b6d4000, ffff88813b6d4c00) Fixes: c62c0a17f9b7 ("netconsole: Append kernel version to message") Signed-off-by: Jakub Kicinski Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260219195021.2099699-1-kuba@kernel.org Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/netconsole.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 9cb4dfc242f5f..f418efb38508c 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1524,7 +1524,8 @@ static void send_msg_no_fragmentation(struct netconsole_target *nt, if (release_len) { release = init_utsname()->release; - scnprintf(nt->buf, MAX_PRINT_CHUNK, "%s,%s", release, msg); + scnprintf(nt->buf, MAX_PRINT_CHUNK, "%s,%.*s", release, + msg_len, msg); msg_len += release_len; } else { memcpy(nt->buf, msg, msg_len); -- 2.51.0