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 B34474086B; Fri, 1 Mar 2024 13:37:01 +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=1709300221; cv=none; b=NBdWpdmOUXxrghJUINq/x+ANZ5xsyi3PZe8sGuAL/darc7ViyzZyzI3tq3Nd6+UWElVtPJahipoPpu0p2RYvjRPH9VY0Th5IC7EXgvK3FupfkcwjX8lTDk3JsIbEmBXTeaOT+nJMqOIaD+1zwwLY211sVKFZrJ1u54+TZCyHzBg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709300221; c=relaxed/simple; bh=wi72/83S5ul2SLiJU9x98yCS+h9zTQektvauzYHFebc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LHcE1KUW17g9B1W2mYtvDFcRmeuzKDqUOTAd7rg69XwdTiBVBBuXVkbb5+Sa92RWgKf45MA+ebM1uzQMJb2cAL6G0SsvpGEYIy6g+2fP6Wy2Em8VgCEBCrQhfHQEOBM0mjnIenFyfkb9WqGk1j3F3rD2bjj+0fR9LFaMgrQJbuM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oYhNoxx8; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oYhNoxx8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F14FC433F1; Fri, 1 Mar 2024 13:36:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709300221; bh=wi72/83S5ul2SLiJU9x98yCS+h9zTQektvauzYHFebc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oYhNoxx81w2FAoe+AW+crPcUNC1KLA6C1VOdSNFjKKmqO6I5ORXJlSlf2F/Uv7RHE qtBBcDmwWLdmh6xufYK0YUlVa2D0171ZGmI5WT3b5DfKrkmA6J9jWVayOd7rstaJIt YDYXmIL1dadqg5BoXJN7jH3/LDWwfDO4UUjUtyeniMDecdMzB1ZZL+/dP3HUCUiYB5 Lsr4EMLJicLRvAu7tY9MnYxTFCsGjAXXXElSUWTtHdhwKcEbIKCtp6bJMDUZIQGluk OMv0mGVFImgavYviaA7Ma/AT87ZYMmL4yOPLfsNCYzNDhVFO7DK9Jmgj3keqhwARmi qA+6MveBa4T3g== Date: Fri, 1 Mar 2024 14:36:55 +0100 From: Christian Brauner To: Luis Henriques Cc: Theodore Ts'o , Andreas Dilger , Alexander Viro , Jan Kara , Miklos Szeredi , Amir Goldstein , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] ext4: fix mount parameters check for empty values Message-ID: <20240301-spalten-impfschutz-4118b8fcf5b3@brauner> References: <20240229163011.16248-1-lhenriques@suse.de> <20240229163011.16248-3-lhenriques@suse.de> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240229163011.16248-3-lhenriques@suse.de> On Thu, Feb 29, 2024 at 04:30:09PM +0000, Luis Henriques wrote: > Now that parameters that have the flag 'fs_param_can_be_empty' set and > their value is NULL are handled as 'flag' type, we need to properly check > for empty (NULL) values. > > Signed-off-by: Luis Henriques > --- > fs/ext4/super.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index 0f931d0c227d..44ba2212dfb3 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -2183,12 +2183,12 @@ static int ext4_parse_param(struct fs_context *fc, struct fs_parameter *param) > switch (token) { > #ifdef CONFIG_QUOTA > case Opt_usrjquota: > - if (!*param->string) > + if (!param->string) > return unnote_qf_name(fc, USRQUOTA); I fail to understand how that can happen. Currently both of these options are parsed as strings via: #define fsparam_string_empty(NAME, OPT) \ __fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL) So if someone sets fsconfig(..., FSCONFIG_SET_STRING, "usrquota", NULL, ...) we give an immediate case FSCONFIG_SET_STRING: if (!_key || !_value || aux) return -EINVAL; from fsconfig() so we know that param->string cannot be NULL. If that were the case we'd NULL deref in fs_param_is_string(): int fs_param_is_string(struct p_log *log, const struct fs_parameter_spec *p, struct fs_parameter *param, struct fs_parse_result *result) { if (param->type != fs_value_is_string || (!*param->string && !(p->flags & fs_param_can_be_empty))) So you're check above seems wrong. If I'm mistaken, please explain, how this can happen in detail.