From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta21.hihonor.com (mta21.honor.com [81.70.160.142]) (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 000182ED17C; Thu, 21 Aug 2025 10:58:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=81.70.160.142 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755773897; cv=none; b=VJsNZFVr4ddyDHMMMpUAnns+FSfbGQqy0UoozePHg/9Cd0dlihNytestWgBroKnAMs3N9+AfoDBUtlNvWfVvRkJCgcQBKVQY6/BiQ1U7mrsXDYCHLQWCZ809aIIhJ8NU3VO04Pzdj6Gd8ZoonVbFTgHrCx579vOadvfNgeFKv2E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755773897; c=relaxed/simple; bh=l3jMKIk6lYIIzI4SccsDJUmeup9tuX38D/XM4qedxQU=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=F86P/nI1SrQC59EanqajbO1vpxMeyFC70j1AIS/uDkfWep58mYI0SqHfMb3BAQ09vmIrQgZBricmsF9H5KmJaE8IGaO94fBEPUMRevkrTtryPQc5Sr3A+yVWFzi6nKTLLtEUm0uA0CqMN0yuhTmNTorsFuL2iCi+Ct/Q6DUW0+E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=honor.com; spf=pass smtp.mailfrom=honor.com; arc=none smtp.client-ip=81.70.160.142 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=honor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=honor.com Received: from w011.hihonor.com (unknown [10.68.20.122]) by mta21.hihonor.com (SkyGuard) with ESMTPS id 4c70fC2v03zYl7h7; Thu, 21 Aug 2025 18:57:55 +0800 (CST) Received: from a011.hihonor.com (10.68.31.243) by w011.hihonor.com (10.68.20.122) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 21 Aug 2025 18:58:08 +0800 Received: from localhost.localdomain (10.144.23.14) by a011.hihonor.com (10.68.31.243) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 21 Aug 2025 18:58:07 +0800 From: wangzijie To: , , , , , , , , CC: , , , , wangzijie Subject: [PATCH v3] proc: fix missing pde_set_flags() for net proc files Date: Thu, 21 Aug 2025 18:58:06 +0800 Message-ID: <20250821105806.1453833-1-wangzijie1@honor.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: w002.hihonor.com (10.68.28.120) To a011.hihonor.com (10.68.31.243) 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(). [1]: https://lore.kernel.org/all/20250815195616.64497967@chagall.paradoxon.rec/ Fixes: ff7ec8dc1b64 ("proc: use the same treatment to check proc_lseek as ones for proc_read_iter et.al") Cc: stable@vger.kernel.org Reported-by: Lars Wendler Signed-off-by: wangzijie --- v3: - followed by Christian's suggestion to stash pde->proc_ops in a local const variable v2: - followed by Jiri's suggestion to refractor code and reformat commit message --- fs/proc/generic.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-) diff --git a/fs/proc/generic.c b/fs/proc/generic.c index 76e800e38..bd0c099cf 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -367,6 +367,25 @@ static const struct inode_operations proc_dir_inode_operations = { .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) @@ -374,6 +393,8 @@ struct proc_dir_entry *proc_register(struct proc_dir_entry *dir, 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) { @@ -561,20 +582,6 @@ struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode, 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) @@ -585,7 +592,6 @@ struct proc_dir_entry *proc_create_data(const char *name, umode_t mode, if (!p) return NULL; p->proc_ops = proc_ops; - pde_set_flags(p); return proc_register(parent, p); } EXPORT_SYMBOL(proc_create_data); @@ -636,7 +642,6 @@ struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode, 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); @@ -667,7 +672,6 @@ struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode, 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); -- 2.25.1