From nobody Fri Jul 24 22:54:52 2026 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 7C03B5464D; Wed, 22 Jul 2026 12:56:02 +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=1784724963; cv=none; b=h8IpIIpXa1qowbDTqAw8a4dosZl4hKW8D9rc2Ka/2XyhF16TaIl2K66aixu2ovu2u5ra9P7Ys0YjCQBmrYqzYCe2rFh2WUwGzHHEaxPdXfJqSwgOUTcAZPOJfy6xlx70ZiWDHDul0J1EnsRfjWEQPvToImtAXGwT03z1IwwnWdQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784724963; c=relaxed/simple; bh=zpeg5d5ytCkhdg46vwRqqadZU8fnyKCySEt0DDguDcU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=mN36pZmEoYhyGh7F9/F6FIT/k49gt2SGQ0TKLe1hxFPGu70q5KF9NnuBRgyLnQEdF6PaXfAMbWhsG++IIAFcgWFpcnpbHJ0nA/L+28gLNi/NwXp8J3D11B+VGrtab9+16l84xlCBw8b8reybYGy4HgstG6hLioIu5yb9GEBccWc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=e7AiHLHK; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="e7AiHLHK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E78E1F000E9; Wed, 22 Jul 2026 12:56:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784724962; bh=Vx/+CsGRRM1h2stz5vle7GBsXwhHi4ckCp1gyGu7hac=; h=From:To:Cc:Subject:Date; b=e7AiHLHKxVJvQqXmEo1GrE3rGlzwC9H0AaNXSSiHoEjc2VXRQColpPxFUmCGs8OVr G1A+j/4SPc9XvyLVV9yKmdPdefSdM17y6lWWYBXIQssa6DVgLjO+VzUGw8yoTXbCvV lCwTPicu1qXi1Wpq19LR1r7jeQgeR1NGRrY14zLwgCtuRZNqVFdwua1nO7yykKF5nN zDUnnApc691jqJMdF0pTY2AANJBoZ96OyJAVGVET7EQ16efEKspHsW4LAepOaSkLLH xgjxDbbSb95rNEzvVWdmfupPLVBX2+5egdAQbMJL3cB7CfZ7K8xjPPkt3uHzwnnw5P bTy3oRJUkbJdQ== From: Leon Romanovsky To: Selvin Xavier , Kalesh AP , Jason Gunthorpe , Leon Romanovsky , Chandramohan Akula Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH rdma-next] RDMA/bnxt_re: Clear VM_MAYWRITE on read-only mmap of driver pages Date: Wed, 22 Jul 2026 15:55:52 +0300 Message-ID: <20260722-missing-vma-write-protection-enforce-v1-1-567cd8499e23@nvidia.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" X-Change-ID: 20260722-missing-vma-write-protection-enforce-2e99624c35dc X-Mailer: b4 0.15-dev-18f8f Content-Transfer-Encoding: quoted-printable From: Leon Romanovsky bnxt_re_mmap() rejects an initially writable mapping of the DBR pacing page and the toggle page, but leaves VM_MAYWRITE set on the accepted read-only mapping. A later mprotect(PROT_READ | PROT_WRITE) therefore passes the mm permission check and upgrades the inserted PTEs, letting userspace write these driver-owned pages: the DBR pacing parameters maintained under rdev->pacing.dbq_lock, and the CQ/SRQ toggle state written from the NQ tasklet. Clear VM_MAYWRITE before vm_insert_page() so the mapping can never be made writable, making any such mprotect() fail with -EACCES while the read-only mapping continues to work. Fixes: ea222485788208 ("RDMA/bnxt_re: Update alloc_page uapi for pacing") Signed-off-by: Leon Romanovsky --- drivers/infiniband/hw/bnxt_re/ib_verbs.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/infiniband/hw/bnxt_re/ib_verbs.c b/drivers/infiniband/= hw/bnxt_re/ib_verbs.c index adc693736769..dcfb1b0ebc22 100644 --- a/drivers/infiniband/hw/bnxt_re/ib_verbs.c +++ b/drivers/infiniband/hw/bnxt_re/ib_verbs.c @@ -4984,12 +4984,15 @@ int bnxt_re_mmap(struct ib_ucontext *ib_uctx, struc= t vm_area_struct *vma) break; case BNXT_RE_MMAP_DBR_PAGE: case BNXT_RE_MMAP_TOGGLE_PAGE: - /* Driver doesn't expect write access for user space */ - if (vma->vm_flags & VM_WRITE) + /* Reject writable mappings and prevent mprotect() upgrades. */ + if (vma->vm_flags & VM_WRITE) { ret =3D -EFAULT; - else - ret =3D vm_insert_page(vma, vma->vm_start, - virt_to_page((void *)bnxt_entry->mem_offset)); + break; + } + + vm_flags_clear(vma, VM_MAYWRITE); + ret =3D vm_insert_page(vma, vma->vm_start, + virt_to_page((void *)bnxt_entry->mem_offset)); break; default: ret =3D -EINVAL; --- base-commit: 0e8e94c15091041ea8910cbfcade5a9c7cfe3f90 change-id: 20260722-missing-vma-write-protection-enforce-2e99624c35dc Best regards, -- =20 Leon Romanovsky