From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 5AB3046F4B8 for ; Tue, 28 Jul 2026 20:34:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785270847; cv=none; b=TidtOZJcxThhIIYNq7/BDLqwKOumsPFxt4bwM1/DXe7YoWp9jHGjjR4BJ2hbdpTeFovsuB8nLLy5R9oOCjPYIK5ajEag/dN+HFpG0bOIWaiB8RFmsf4STzZ9vL9GHgEk5vH4zggHxejuiUYG1pgbmrKHJV68txQwgsLM/K3z5bs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785270847; c=relaxed/simple; bh=OskdLpIbABB2AmTd1ojCfz6jwFlku/RgfQmsOH0bjwk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DGX1r+DbSDadAZqNMKofoP8ppgQsYnJ5Di3wVowkw4aXKR96MN+6lguUlSNy2gn9kLYlQ27cYR4TO81kKkmOiar8lwfK1E7u2+O64rorPB51CYIzdVsUd9I/cwx6FEJQo/PMlZfzjSGCU0JRme5LB3oLVuKqkEMikYTVN2n5wWI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=P7tAVN48; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="P7tAVN48" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1785270844; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=NadbsigzlfpEpTT1POIr4Z/BIVqOZxQfrFeEDio9Ik4=; b=P7tAVN48GJrlVFSBKu8iI3ZRW6HxETlRhsZGRKSqmBDe9WJbwrgPY7PT5ZEAZaAqgLnMh0 YF1HsNDuqdBX6mE/B+916f1woa+0JYIJ/g/aRzVbTOz1U2qLfxLHhoTwnUVx237sukIaTa ODPAsSHnGgrnvP7tpa5cgPOKn1AKUr4= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-648-vUphpVblPqWsFFmnst8d6A-1; Tue, 28 Jul 2026 16:34:00 -0400 X-MC-Unique: vUphpVblPqWsFFmnst8d6A-1 X-Mimecast-MFC-AGG-ID: vUphpVblPqWsFFmnst8d6A_1785270839 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5405918002C3; Tue, 28 Jul 2026 20:33:59 +0000 (UTC) Received: from madcap2.tricolour.ca (unknown [10.22.58.2]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5B47F414; Tue, 28 Jul 2026 20:33:56 +0000 (UTC) Date: Tue, 28 Jul 2026 16:33:53 -0400 From: Richard Guy Briggs To: Ricardo Robaina Cc: audit@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, paul@paul-moore.com, eparis@redhat.com, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, sgrubb@redhat.com Subject: Re: [PATCH v2] audit: add FSCONFIG auxiliary record to log filesystem configuration Message-ID: References: <20260727173710.964626-1-rrobaina@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260727173710.964626-1-rrobaina@redhat.com> X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 On 2026-07-27 14:37, Ricardo Robaina wrote: > Modern mount tools (util-linux >= 2.39.1) use the new mount API > (fsopen, fsconfig, fsmount, move_mount) instead of the legacy mount(2) > syscall. The generic SYSCALL audit record logs the fsconfig syscall but > does not capture the configuration parameters, creating an audit gap for > critical mount information such as the device being mounted. > > Add an FSCONFIG auxiliary record that logs the command type, parameter > name (key), parameter value, and aux parameter passed to fsconfig(2). > > ---- > type=SYSCALL : syscall=fsconfig ... a1=FSCONFIG_SET_STRING ... > type=FSCONFIG : fs_cmd=1 fs_key=source fs_val="tmpfs" fs_aux=0 > ---- > type=SYSCALL : syscall=fsconfig ... a1=FSCONFIG_CMD_CREATE ... > type=FSCONFIG : fs_cmd=6 fs_key=(null) fs_val=(null) fs_aux=0 > ---- > type=SYSCALL : syscall=fsconfig ... a1=FSCONFIG_SET_BINARY ... > type=FSCONFIG : fs_cmd=2 fs_key=hidepid fs_val="" fs_aux=4 > > Link: https://github.com/linux-audit/audit-kernel/issues/153 > Acked-by: Christian Brauner > Signed-off-by: Ricardo Robaina Reviewed-by: Richard Guy Briggs > --- > Changes in v2: > - Fixed null-check for fs_key field. > - Clarified trimmed SYSCALL output in commit message examples. > > fs/fsopen.c | 7 +++++++ > include/linux/audit.h | 13 +++++++++++++ > include/uapi/linux/audit.h | 1 + > kernel/auditsc.c | 27 +++++++++++++++++++++++++++ > 4 files changed, 48 insertions(+) > > diff --git a/fs/fsopen.c b/fs/fsopen.c > index ae19e5136598..9b3c02f59df4 100644 > --- a/fs/fsopen.c > +++ b/fs/fsopen.c > @@ -15,6 +15,7 @@ > #include > #include > #include > +#include > #include "internal.h" > #include "mount.h" > > @@ -357,6 +358,7 @@ SYSCALL_DEFINE5(fsconfig, > struct fs_context *fc; > int ret; > int lookup_flags = 0; > + const char *value_str = NULL; > > struct fs_parameter param = { > .type = fs_value_is_undefined, > @@ -423,6 +425,7 @@ SYSCALL_DEFINE5(fsconfig, > goto out_key; > } > param.size = strlen(param.string); > + value_str = param.string; > break; > case FSCONFIG_SET_BINARY: > param.type = fs_value_is_blob; > @@ -432,6 +435,7 @@ SYSCALL_DEFINE5(fsconfig, > ret = PTR_ERR(param.blob); > goto out_key; > } > + value_str = ""; > break; > case FSCONFIG_SET_PATH_EMPTY: > lookup_flags = LOOKUP_EMPTY; > @@ -445,6 +449,7 @@ SYSCALL_DEFINE5(fsconfig, > } > param.dirfd = aux; > param.size = strlen(param.name->name); > + value_str = param.name->name; > break; > case FSCONFIG_SET_FD: > param.type = fs_value_is_file; > @@ -458,6 +463,8 @@ SYSCALL_DEFINE5(fsconfig, > break; > } > > + audit_log_fsconfig(cmd, param.key, value_str, aux); > + > ret = mutex_lock_interruptible(&fc->uapi_mutex); > if (ret == 0) { > ret = vfs_fsconfig_locked(fc, cmd, ¶m); > diff --git a/include/linux/audit.h b/include/linux/audit.h > index 45abb3722d30..978eb881974c 100644 > --- a/include/linux/audit.h > +++ b/include/linux/audit.h > @@ -449,6 +449,8 @@ extern void __audit_tk_injoffset(struct timespec64 offset); > extern void __audit_ntp_log(const struct audit_ntp_data *ad); > extern void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries, > enum audit_nfcfgop op, gfp_t gfp); > +extern void __audit_log_fsconfig(unsigned int cmd, const char *key, > + const char *value, int aux); > > static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp) > { > @@ -598,6 +600,13 @@ static inline void audit_log_nfcfg(const char *name, u8 af, > __audit_log_nfcfg(name, af, nentries, op, gfp); > } > > +static inline void audit_log_fsconfig(unsigned int cmd, const char *key, > + const char *value, int aux) > +{ > + if (!audit_dummy_context()) > + __audit_log_fsconfig(cmd, key, value, aux); > +} > + > extern int audit_n_rules; > extern int audit_signals; > #else /* CONFIG_AUDITSYSCALL */ > @@ -730,6 +739,10 @@ static inline void audit_log_nfcfg(const char *name, u8 af, > enum audit_nfcfgop op, gfp_t gfp) > { } > > +static inline void audit_log_fsconfig(unsigned int cmd, const char *key, > + const char *value, int aux) > +{ } > + > #define audit_n_rules 0 > #define audit_signals 0 > #endif /* CONFIG_AUDITSYSCALL */ > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h > index e8f5ce677df7..5cd0eb602528 100644 > --- a/include/uapi/linux/audit.h > +++ b/include/uapi/linux/audit.h > @@ -122,6 +122,7 @@ > #define AUDIT_OPENAT2 1337 /* Record showing openat2 how args */ > #define AUDIT_DM_CTRL 1338 /* Device Mapper target control */ > #define AUDIT_DM_EVENT 1339 /* Device Mapper events */ > +#define AUDIT_FSCONFIG 1341 /* Record showing fsconfig args */ > > #define AUDIT_AVC 1400 /* SE Linux avc denial or grant */ > #define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */ > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > index 6610e667c728..fefc5c5dd4aa 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -2882,6 +2882,33 @@ void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries, > } > EXPORT_SYMBOL_GPL(__audit_log_nfcfg); > > +void __audit_log_fsconfig(unsigned int cmd, const char *key, > + const char *value, int aux) > +{ > + struct audit_buffer *ab; > + > + ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FSCONFIG); > + if (!ab) > + return; > + > + audit_log_format(ab, "fs_cmd=%u", cmd); > + audit_log_format(ab, " fs_key="); > + if (key) > + audit_log_untrustedstring(ab, key); > + else > + audit_log_format(ab, "(null)"); > + > + audit_log_format(ab, " fs_val="); > + if (value) > + audit_log_untrustedstring(ab, value); > + else > + audit_log_format(ab, "(null)"); > + > + audit_log_format(ab, " fs_aux=%d", aux); > + > + audit_log_end(ab); > +} > + > static void audit_log_task(struct audit_buffer *ab) > { > kuid_t auid, uid; > -- > 2.53.0 > - RGB -- Richard Guy Briggs Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada Upstream IRC: SunRaycer Voice: +1.613.860 2354 SMS: +1.613.518.6570