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 C225851D520; Wed, 30 Sep 2026 17:26:01 +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=1790789163; cv=none; b=jQjwFy35Y12JuHYhJEXHnK5XAKv48npcKJ+tO4xRiPRRBM36DevZpLKi8l2B9d7Nr63MDJB4xec4dvxmDZly5MyI5tw8dhUTMiYXjIxuPRUMn2tnaT6RgB8SxNEvBiXn8THoSdqV7Ah0svYxZN0dS0amZ6z9RQGOGVI3OKC5Dog= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790789163; c=relaxed/simple; bh=wP5GAexNhmYNJMDtXmNUcFXnQP2g/c7HqDrsLdf9hJo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hNK2Lc34p9UB37quWkSPnObSADg6TuiaWsYcTWRqUdumpKZmoMsEcbUDPCM/kFImFqsE0Zc3HhV4HlWVT8PXvJNWdq7bKzrvdSrpDD01Wi+J1bH+qGynCN0jcLOwTTG5T1eewFuxdB8o+gd5IeicIOTWPoRE2TZ1FuT48kWBD1E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RXk0da6H; 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="RXk0da6H" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2014A1F00898; Wed, 30 Sep 2026 17:26:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790789161; bh=y42632uV5UudBqd1gDRLowa5Y3cj7uE+iNslM4We3Q8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RXk0da6HFJUS85ZUkbmO1OdPN0OQy5F59EGoVtgVbBXSz7hSoAZZjn8gXdmzIwpCb HLgfrTqsGC7VOJff78V+w8AhRVi+fi4uR9camv4NVxfWIJlpv3H1i5Qt1JGk/RXeX+ ChbToCCgz7uLcfJthfOD1nJrIWabjAGV+URtU4wo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zeng Heng , Catalin Marinas , Will Deacon , Sasha Levin Subject: [PATCH 6.12 353/877] arm64: io: Reject non-user protection in ioremap_prot() Date: Wed, 30 Sep 2026 17:21:04 +0200 Message-ID: <20260930152422.290032236@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152414.738996857@linuxfoundation.org> References: <20260930152414.738996857@linuxfoundation.org> User-Agent: quilt/0.69 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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zeng Heng [ Upstream commit bb756b11ad63832ebee58caf9e8f9381eaecff9f ] Mapping a stack-top page via /dev/mem with PROT_NONE and then reading that process's /proc//cmdline triggers a spurious WARN in ioremap_prot() through generic_access_phys(): WARNING: ./arch/arm64/include/asm/io.h:275 at generic_access_phys Call trace: generic_access_phys+0x1c8/0x228 (P) __access_remote_vm+0x2b4/0x398 access_remote_vm+0x14/0x30 get_mm_cmdline+0xf8/0x2a0 proc_pid_cmdline_read+0x68/0x120 generic_access_phys() passes the protection derived from the user PTE to ioremap_prot(). On arm64, a PROT_NONE mapping is represented by a present-invalid PTE, so pte_present() still returns true and the protection reaches ioremap_prot(). A PROT_NONE mapping does not have PTE_USER, causing the existing WARN_ON_ONCE() in ioremap_prot() to fire even though this is a valid user mapping. Execute-only mappings have the same issue and must not be readable through this path either. ioremap_prot() should therefore reject protection values without PTE_USER without warning. This makes the access fail cleanly for PROT_NONE and execute-only mappings while retaining the existing user-protection contract. Fixes: 8f098037139b ("arm64: io: Extract user memory type in ioremap_prot()") Signed-off-by: Zeng Heng Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/include/asm/io.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h index 46bd37707e080..16a423101bdcd 100644 --- a/arch/arm64/include/asm/io.h +++ b/arch/arm64/include/asm/io.h @@ -282,7 +282,8 @@ static inline void __iomem *ioremap_prot(phys_addr_t phys, size_t size, pgprot_t prot; pteval_t user_prot_val = pgprot_val(__pgprot(user_prot)); - if (WARN_ON_ONCE(!(user_prot_val & PTE_USER))) + /* Reject PROT_NONE and exec-only */ + if (!(user_prot_val & PTE_USER)) return NULL; prot = __pgprot_modify(PAGE_KERNEL, PTE_ATTRINDX_MASK, -- 2.53.0