From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 69E7143FD23 for ; Wed, 15 Jul 2026 10:24:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784111072; cv=none; b=VEWflKLPNjWaVDimCCLWQJV900X7a1Rc20aBfc/3i3cnwLNPKG2sFsUgYdrGS8VU0DZcVNws/ufaewjaPcqtm56KyYgHyemSBZTd7/r14dBAqRE77qjuiirn6wWZ/HWTRyX5+6f/2kdWvRfPOXG8efn6KoSLZkK4m8fljK8YfOY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784111072; c=relaxed/simple; bh=xhjidImzELu7vieorAoBtCTZ7JKABVbzGewTM5YV39g=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=PnGebTa8kcB1Fo1Nq1y2EZvRmythqeCp+rDijhSmBlUzKTqoLigBiP9rygdyjcB0R2+1YoXB0Xnx9A43TfAuZTqGAgGhrk59N7CnnMca/PzummddiEbp17623u4niFangtcvoY/tdyVzXiusx/SAXnetJE5Zi+QBnMRNklCEpf4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ym84jQpP; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Ym84jQpP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D06AB1F000E9; Wed, 15 Jul 2026 10:24:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784111071; bh=mhwwxYaTelbAXcsenUhPBKqeR/nMRQtm0HnO8isp6Ys=; h=Subject:To:Cc:From:Date; b=Ym84jQpPJ4gxl8jLqANg4U8hhlUixx9ADkkLDEnoQzLKfb1jt6T7HxxVavTeRNO/y qslXTGlGO5XggrOqae+2sKYguRoCB7kxkhG5YkkGOkQbcZ9VL6lXZ4iOkdIZOytvsh blyZCkIlUmO6+EbTDmhhsVJSGHuRo/CMPmwmi8l0= Subject: FAILED: patch "[PATCH] nvmet: fix pre-auth out-of-bounds heap read in Discovery Get" failed to apply to 5.10-stable tree To: hexlabsecurity@proton.me,hch@lst.de,kbusch@kernel.org,kch@nvidia.com Cc: From: Date: Wed, 15 Jul 2026 12:20:42 +0200 Message-ID: <2026071542-blip-estate-70e4@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 53cd102a7a56079b11b897835bd9b94c14e6322c # git commit -s git send-email --to '' --in-reply-to '2026071542-blip-estate-70e4@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 53cd102a7a56079b11b897835bd9b94c14e6322c Mon Sep 17 00:00:00 2001 From: Bryam Vargas Date: Wed, 27 May 2026 15:00:00 -0500 Subject: [PATCH] nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page nvmet_execute_disc_get_log_page() validates only the dword alignment of the host-supplied Log Page Offset (lpo). The 64-bit offset is then added to a small kzalloc'd buffer that holds the discovery log page and the result is passed straight to nvmet_copy_to_sgl(), which memcpy()s data_len bytes out to the host with no source-side bound check: u64 offset = nvmet_get_log_page_offset(req->cmd); /* 64-bit host */ size_t data_len = nvmet_get_log_page_len(req->cmd); /* 32-bit host */ ... if (offset & 0x3) { ... } /* only check */ ... alloc_len = sizeof(*hdr) + entry_size * discovery_log_entries(req); buffer = kzalloc(alloc_len, GFP_KERNEL); ... status = nvmet_copy_to_sgl(req, 0, buffer + offset, data_len); The Discovery controller is unauthenticated -- nvmet_host_allowed() returns true unconditionally for the discovery subsystem -- so the call is reachable pre-authentication by any TCP/RDMA/FC peer that can reach the nvmet target. With a discovery log page of ~1 KiB, an attacker requesting up to 4 KiB starting at offset == alloc_len reads the next slab page out and gets its content returned over the fabric (an empirical run on a default nvmet-tcp loopback target leaked 81 canonical kernel pointers in one Get Log Page response). Pointing the offset at unmapped kernel memory faults the in-kernel memcpy and crashes (or panics, on panic_on_oops=1) the target host instead. The attacker-controlled source-side offset pattern "nvmet_copy_to_sgl(req, 0, buffer + ATTACKER_OFFSET, ...)" is unique to nvmet_execute_disc_get_log_page in the entire nvmet codebase: every other Get Log Page handler in admin-cmd.c either ignores lpo (and silently starts every response at offset 0) or tracks a local destination offset with a fixed source pointer. Validate the host-supplied offset against the log page size, cap the copy length to what is actually available, and zero-fill any remainder of the host transfer buffer. The zero-fill matches the existing short-response pattern in nvmet_execute_get_log_changed_ns() (admin-cmd.c) and prevents leaking transport SGL contents when the host asks for more bytes than the log page contains. Fixes: a07b4970f464 ("nvmet: add a generic NVMe target") Cc: stable@vger.kernel.org Reviewed-by: Chaitanya Kulkarni Reviewed-by: Christoph Hellwig Signed-off-by: Bryam Vargas Signed-off-by: Keith Busch diff --git a/drivers/nvme/target/discovery.c b/drivers/nvme/target/discovery.c index e9b35549e254..114869d16a1f 100644 --- a/drivers/nvme/target/discovery.c +++ b/drivers/nvme/target/discovery.c @@ -166,6 +166,7 @@ static void nvmet_execute_disc_get_log_page(struct nvmet_req *req) u64 offset = nvmet_get_log_page_offset(req->cmd); size_t data_len = nvmet_get_log_page_len(req->cmd); size_t alloc_len; + size_t copy_len; struct nvmet_subsys_link *p; struct nvmet_port *r; u32 numrec = 0; @@ -242,7 +243,27 @@ static void nvmet_execute_disc_get_log_page(struct nvmet_req *req) up_read(&nvmet_config_sem); - status = nvmet_copy_to_sgl(req, 0, buffer + offset, data_len); + /* + * Validate the host-supplied log page offset before copying out. + * Without this check, the host controls a 64-bit byte offset into + * a small kzalloc'd buffer: a value past the log page lets the + * subsequent memcpy read adjacent kernel heap, and a value aimed + * at unmapped kernel memory faults the in-kernel copy and crashes + * the target host. The Discovery controller is unauthenticated, + * so the bug is reachable from any reachable fabric peer. + */ + if (offset > alloc_len) { + req->error_loc = + offsetof(struct nvme_get_log_page_command, lpo); + status = NVME_SC_INVALID_FIELD | NVME_STATUS_DNR; + goto out_free_buffer; + } + + copy_len = min_t(size_t, data_len, alloc_len - offset); + status = nvmet_copy_to_sgl(req, 0, buffer + offset, copy_len); + if (!status && copy_len < data_len) + status = nvmet_zero_sgl(req, copy_len, data_len - copy_len); +out_free_buffer: kfree(buffer); out: nvmet_req_complete(req, status);