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 A53331E572F; Sun, 7 Sep 2025 20:45:31 +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=1757277931; cv=none; b=eiml70/q7wXSsRzd+LJUZEhdCmHDqH0h2y7uqXJJK821PTYgfTYTU8asw23T8Li0TcpXoWlfIXcM5NhWgezqI4vuzKbsUoielTuVqcTNc78YvzdIjUTDA9tez3ATyabLb3+y4YF0O36+ZbandK9RhyvEdaBTiinIjibj9Xs7IMs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757277931; c=relaxed/simple; bh=35CRD2ebdJsvdQz51fv1Hyb+WKEYiEHlNUi668VQRxA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=sktUyIn+uIhYpMr10cWEQFL/mehyBLgBctbzgAiKkCNA7Px5wFc//J17sqfRi70CSZEiAugj7JhfmDN0P5HT1FXGtjnbYJHL9ZrYVAo7vtFn0QwGwqWrwdgyoKq6O1oXiS69GBMGWFxhotqklem0VUh6U1b58gCrwr+rWgtJGdc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=JwYNlRkW; 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="JwYNlRkW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0C14C4CEF0; Sun, 7 Sep 2025 20:45:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1757277931; bh=35CRD2ebdJsvdQz51fv1Hyb+WKEYiEHlNUi668VQRxA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JwYNlRkWDIr5mRZ8F7u/47jkp9oC01BahkDXhnT4RBJ+EC4r3amFU24rll/7Cis+7 JQaBxg6bLRZ6u0tgCgFqoaYFHXdfYWS1fLjtrNuVVp/sExpe5an5RG4gHHMrY0eoyn Dn3QqCPdR0PPqY9/r9bx6j673YBoLJu0M2xz0/8s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, wangzijie , Lars Wendler , Stefano Brivio , =?UTF-8?q?Petr=20Van=C4=9Bk?= , Alexei Starovoitov , Alexey Dobriyan , Al Viro , "Edgecombe, Rick P" , Jiri Slaby , "Kirill A. Shutemov" , Andrew Morton Subject: [PATCH 6.16 114/183] proc: fix missing pde_set_flags() for net proc files Date: Sun, 7 Sep 2025 21:59:01 +0200 Message-ID: <20250907195618.500506635@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250907195615.802693401@linuxfoundation.org> References: <20250907195615.802693401@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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: wangzijie commit 2ce3d282bd5050fca8577defeff08ada0d55d062 upstream. To avoid potential UAF issues during module removal races, we use pde_set_flags() to save proc_ops flags in PDE itself before proc_register(), and then use pde_has_proc_*() helpers instead of directly dereferencing pde->proc_ops->*. However, the pde_set_flags() call was missing when creating net related proc files. This omission caused incorrect behavior which FMODE_LSEEK was being cleared inappropriately in proc_reg_open() for net proc files. Lars reported it in this link[1]. Fix this by ensuring pde_set_flags() is called when register proc entry, and add NULL check for proc_ops in pde_set_flags(). [wangzijie1@honor.com: stash pde->proc_ops in a local const variable, per Christian] Link: https://lkml.kernel.org/r/20250821105806.1453833-1-wangzijie1@honor.com Link: https://lkml.kernel.org/r/20250818123102.959595-1-wangzijie1@honor.com Link: https://lore.kernel.org/all/20250815195616.64497967@chagall.paradoxon.rec/ [1] Fixes: ff7ec8dc1b64 ("proc: use the same treatment to check proc_lseek as ones for proc_read_iter et.al") Signed-off-by: wangzijie Reported-by: Lars Wendler Tested-by: Stefano Brivio Tested-by: Petr Vaněk Tested by: Lars Wendler Cc: Alexei Starovoitov Cc: Alexey Dobriyan Cc: Al Viro Cc: "Edgecombe, Rick P" Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: Kirill A. Shutemov Cc: wangzijie Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/proc/generic.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-) --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -364,6 +364,25 @@ static const struct inode_operations pro .setattr = proc_notify_change, }; +static void pde_set_flags(struct proc_dir_entry *pde) +{ + const struct proc_ops *proc_ops = pde->proc_ops; + + if (!proc_ops) + return; + + if (proc_ops->proc_flags & PROC_ENTRY_PERMANENT) + pde->flags |= PROC_ENTRY_PERMANENT; + if (proc_ops->proc_read_iter) + pde->flags |= PROC_ENTRY_proc_read_iter; +#ifdef CONFIG_COMPAT + if (proc_ops->proc_compat_ioctl) + pde->flags |= PROC_ENTRY_proc_compat_ioctl; +#endif + if (proc_ops->proc_lseek) + pde->flags |= PROC_ENTRY_proc_lseek; +} + /* returns the registered entry, or frees dp and returns NULL on failure */ struct proc_dir_entry *proc_register(struct proc_dir_entry *dir, struct proc_dir_entry *dp) @@ -371,6 +390,8 @@ struct proc_dir_entry *proc_register(str if (proc_alloc_inum(&dp->low_ino)) goto out_free_entry; + pde_set_flags(dp); + write_lock(&proc_subdir_lock); dp->parent = dir; if (pde_subdir_insert(dir, dp) == false) { @@ -559,20 +580,6 @@ struct proc_dir_entry *proc_create_reg(c return p; } -static void pde_set_flags(struct proc_dir_entry *pde) -{ - if (pde->proc_ops->proc_flags & PROC_ENTRY_PERMANENT) - pde->flags |= PROC_ENTRY_PERMANENT; - if (pde->proc_ops->proc_read_iter) - pde->flags |= PROC_ENTRY_proc_read_iter; -#ifdef CONFIG_COMPAT - if (pde->proc_ops->proc_compat_ioctl) - pde->flags |= PROC_ENTRY_proc_compat_ioctl; -#endif - if (pde->proc_ops->proc_lseek) - pde->flags |= PROC_ENTRY_proc_lseek; -} - struct proc_dir_entry *proc_create_data(const char *name, umode_t mode, struct proc_dir_entry *parent, const struct proc_ops *proc_ops, void *data) @@ -583,7 +590,6 @@ struct proc_dir_entry *proc_create_data( if (!p) return NULL; p->proc_ops = proc_ops; - pde_set_flags(p); return proc_register(parent, p); } EXPORT_SYMBOL(proc_create_data); @@ -634,7 +640,6 @@ struct proc_dir_entry *proc_create_seq_p p->proc_ops = &proc_seq_ops; p->seq_ops = ops; p->state_size = state_size; - pde_set_flags(p); return proc_register(parent, p); } EXPORT_SYMBOL(proc_create_seq_private); @@ -665,7 +670,6 @@ struct proc_dir_entry *proc_create_singl return NULL; p->proc_ops = &proc_single_ops; p->single_show = show; - pde_set_flags(p); return proc_register(parent, p); } EXPORT_SYMBOL(proc_create_single_data);