Re: [PATCH v1 2/4] exports: Add an xprtsec= export option

[Jeff Layton <jlayton@kernel.org>]

On Mon, 2023-03-20 at 10:35 -0400, Chuck Lever wrote:
> From: Chuck Lever <chuck.lever@oracle.com>
> 
> The overall goal is to enable administrators to require the use of
> transport layer security when clients access particular exports.
> 
> This patch adds support to exportfs to parse and display a new
> xprtsec= export option. The setting is not yet passed to the kernel.
> 
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  support/include/nfs/export.h |    6 +++
>  support/include/nfslib.h     |   14 +++++++
>  support/nfs/exports.c        |   85 ++++++++++++++++++++++++++++++++++++++++++
>  utils/exportfs/exportfs.c    |    1 
>  4 files changed, 106 insertions(+)
> 
> diff --git a/support/include/nfs/export.h b/support/include/nfs/export.h
> index 0eca828ee3ad..b29c6fa4f554 100644
> --- a/support/include/nfs/export.h
> +++ b/support/include/nfs/export.h
> @@ -40,4 +40,10 @@
>  #define NFSEXP_OLD_SECINFO_FLAGS (NFSEXP_READONLY | NFSEXP_ROOTSQUASH \
>  					| NFSEXP_ALLSQUASH)
>  
> +enum {
> +	NFSEXP_XPRTSEC_NONE = 1,
> +	NFSEXP_XPRTSEC_TLS = 2,
> +	NFSEXP_XPRTSEC_MTLS = 3,
> +};
> +

Can we put these into a uapi header somewhere and then just have
nfs-utils use those if they're defined?

>  #endif /* _NSF_EXPORT_H */
> diff --git a/support/include/nfslib.h b/support/include/nfslib.h
> index 6faba71bf0cd..9a188fb84790 100644
> --- a/support/include/nfslib.h
> +++ b/support/include/nfslib.h
> @@ -62,6 +62,18 @@ struct sec_entry {
>  	int flags;
>  };
>  
> +#define XPRTSECMODE_COUNT 4
> +
> +struct xprtsec_info {
> +	const char		*name;
> +	int			number;
> +};
> +
> +struct xprtsec_entry {
> +	const struct xprtsec_info *info;
> +	int			flags;
> +};
> +
>  /*
>   * Data related to a single exports entry as returned by getexportent.
>   * FIXME: export options should probably be parsed at a later time to
> @@ -83,6 +95,7 @@ struct exportent {
>  	char *          e_fslocdata;
>  	char *		e_uuid;
>  	struct sec_entry e_secinfo[SECFLAVOR_COUNT+1];
> +	struct xprtsec_entry e_xprtsec[XPRTSECMODE_COUNT + 1];
>  	unsigned int	e_ttl;
>  	char *		e_realpath;
>  };
> @@ -99,6 +112,7 @@ struct rmtabent {
>  void			setexportent(char *fname, char *type);
>  struct exportent *	getexportent(int,int);
>  void 			secinfo_show(FILE *fp, struct exportent *ep);
> +void			xprtsecinfo_show(FILE *fp, struct exportent *ep);
>  void			putexportent(struct exportent *xep);
>  void			endexportent(void);
>  struct exportent *	mkexportent(char *hname, char *path, char *opts);
> diff --git a/support/nfs/exports.c b/support/nfs/exports.c
> index 7f12383981c3..da8ace3a65fd 100644
> --- a/support/nfs/exports.c
> +++ b/support/nfs/exports.c
> @@ -99,6 +99,7 @@ static void init_exportent (struct exportent *ee, int fromkernel)
>  	ee->e_fslocmethod = FSLOC_NONE;
>  	ee->e_fslocdata = NULL;
>  	ee->e_secinfo[0].flav = NULL;
> +	ee->e_xprtsec[0].info = NULL;
>  	ee->e_nsquids = 0;
>  	ee->e_nsqgids = 0;
>  	ee->e_uuid = NULL;
> @@ -248,6 +249,17 @@ void secinfo_show(FILE *fp, struct exportent *ep)
>  	}
>  }
>  
> +void xprtsecinfo_show(FILE *fp, struct exportent *ep)
> +{
> +	struct xprtsec_entry *p1, *p2;
> +
> +	for (p1 = ep->e_xprtsec; p1->info; p1 = p2) {
> +		fprintf(fp, ",xprtsec=%s", p1->info->name);
> +		for (p2 = p1 + 1; p2->info && (p1->flags == p2->flags); p2++)
> +			fprintf(fp, ":%s", p2->info->name);
> +	}
> +}
> +
>  static void
>  fprintpath(FILE *fp, const char *path)
>  {
> @@ -344,6 +356,7 @@ putexportent(struct exportent *ep)
>  	}
>  	fprintf(fp, "anonuid=%d,anongid=%d", ep->e_anonuid, ep->e_anongid);
>  	secinfo_show(fp, ep);
> +	xprtsecinfo_show(fp, ep);
>  	fprintf(fp, ")\n");
>  }
>  
> @@ -482,6 +495,75 @@ static unsigned int parse_flavors(char *str, struct exportent *ep)
>  	return out;
>  }
>  
> +static const struct xprtsec_info xprtsec_name2info[] = {
> +	{ "none",	NFSEXP_XPRTSEC_NONE },
> +	{ "tls",	NFSEXP_XPRTSEC_TLS },
> +	{ "mtls",	NFSEXP_XPRTSEC_MTLS },
> +	{ NULL,		0 }
> +};
> +
> +static const struct xprtsec_info *find_xprtsec_info(const char *name)
> +{
> +	const struct xprtsec_info *info;
> +
> +	for (info = xprtsec_name2info; info->name; info++)
> +		if (strcmp(info->name, name) == 0)
> +			return info;
> +	return NULL;
> +}
> +
> +/*
> + * Append the given xprtsec mode to the exportent's e_xprtsec array,
> + * or do nothing if it's already there. Returns the index of flavor in
> + * the resulting array in any case.
> + */
> +static int xprtsec_addmode(const struct xprtsec_info *info, struct exportent *ep)
> +{
> +	struct xprtsec_entry *p;
> +
> +	for (p = ep->e_xprtsec; p->info; p++)
> +		if (p->info == info || p->info->number == info->number)
> +			return p - ep->e_xprtsec;
> +
> +	if (p - ep->e_xprtsec >= XPRTSECMODE_COUNT) {
> +		xlog(L_ERROR, "more than %d xprtsec modes on an export\n",
> +			XPRTSECMODE_COUNT);
> +		return -1;
> +	}
> +	p->info = info;
> +	p->flags = ep->e_flags;
> +	(p + 1)->info = NULL;
> +	return p - ep->e_xprtsec;
> +}
> +
> +/*
> + * @str is a colon seperated list of transport layer security modes.
> + * Their order is recorded in @ep, and a bitmap corresponding to the
> + * list is returned.
> + *
> + * A zero return indicates an error.
> + */
> +static unsigned int parse_xprtsec(char *str, struct exportent *ep)
> +{
> +	unsigned int out = 0;
> +	char *name;
> +
> +	while ((name = strsep(&str, ":"))) {
> +		const struct xprtsec_info *info = find_xprtsec_info(name);
> +		int bit;
> +
> +		if (!info) {
> +			xlog(L_ERROR, "unknown xprtsec mode %s\n", name);
> +			return 0;
> +		}
> +		bit = xprtsec_addmode(info, ep);
> +		if (bit < 0)
> +			return 0;
> +		out |= 1 << bit;
> +	}
> +	return out;
> +}
> +
>  /* Sets the bits in @mask for the appropriate security flavor flags. */
>  static void setflags(int mask, unsigned int active, struct exportent *ep)
>  {
> @@ -687,6 +769,9 @@ bad_option:
>  			active = parse_flavors(opt+4, ep);
>  			if (!active)
>  				goto bad_option;
> +		} else if (strncmp(opt, "xprtsec=", 8) == 0) {
> +			if (!parse_xprtsec(opt + 8, ep))
> +				goto bad_option;
>  		} else {
>  			xlog(L_ERROR, "%s:%d: unknown keyword \"%s\"\n",
>  					flname, flline, opt);
> diff --git a/utils/exportfs/exportfs.c b/utils/exportfs/exportfs.c
> index 6d79a5b3480d..37b9e4b3612d 100644
> --- a/utils/exportfs/exportfs.c
> +++ b/utils/exportfs/exportfs.c
> @@ -743,6 +743,7 @@ dump(int verbose, int export_format)
>  #endif
>  			}
>  			secinfo_show(stdout, ep);
> +			xprtsecinfo_show(stdout, ep);
>  			printf("%c\n", (c != '(')? ')' : ' ');
>  		}
>  	}
> 
> 

-- 
Jeff Layton <jlayton@kernel.org>