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From:   Scott Mayhew <smayhew@redhat.com>
To:     anna.schumaker@netapp.com, trond.myklebust@hammerspace.com
Cc:     dhowells@redhat.com, viro@zeniv.linux.org.uk,
        linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org
Subject: [PATCH v6 21/27] NFS: Add a small buffer in nfs_fs_context to avoid string dup
Date:   Tue, 10 Dec 2019 07:31:09 -0500
Message-Id: <20191210123115.1655-22-smayhew@redhat.com>
In-Reply-To: <20191210123115.1655-1-smayhew@redhat.com>
References: <20191210123115.1655-1-smayhew@redhat.com>
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: quoted-printable
Sender: linux-nfs-owner@vger.kernel.org
Precedence: bulk

From: David Howells <dhowells@redhat.com>

Add a small buffer in nfs_fs_context to avoid string duplication when
parsing numbers.  Also make the parsing function wrapper place the parsed
integer directly in the appropriate nfs_fs_context struct member.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/nfs/fs_context.c | 98 +++++++++++++++++++++------------------------
 fs/nfs/internal.h   |  2 +
 2 files changed, 48 insertions(+), 52 deletions(-)

diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
index 92a1e4bd9133..2921c5820c31 100644
--- a/fs/nfs/fs_context.c
+++ b/fs/nfs/fs_context.c
@@ -468,27 +468,38 @@ static int nfs_get_option_str(substring_t args[], cha=
r **option)
 =09return !*option;
 }
=20
-static int nfs_get_option_ul(substring_t args[], unsigned long *option)
+static int nfs_get_option_ui(struct nfs_fs_context *ctx,
+=09=09=09     substring_t args[], unsigned int *option)
 {
-=09int rc;
-=09char *string;
+=09match_strlcpy(ctx->buf, args, sizeof(ctx->buf));
+=09return kstrtouint(ctx->buf, 10, option);
+}
=20
-=09string =3D match_strdup(args);
-=09if (string =3D=3D NULL)
-=09=09return -ENOMEM;
-=09rc =3D kstrtoul(string, 10, option);
-=09kfree(string);
+static int nfs_get_option_ui_bound(struct nfs_fs_context *ctx,
+=09=09=09=09   substring_t args[], unsigned int *option,
+=09=09=09=09   unsigned int l_bound, unsigned u_bound)
+{
+=09int ret;
=20
-=09return rc;
+=09match_strlcpy(ctx->buf, args, sizeof(ctx->buf));
+=09ret =3D kstrtouint(ctx->buf, 10, option);
+=09if (ret < 0)
+=09=09return ret;
+=09if (*option < l_bound || *option > u_bound)
+=09=09return -ERANGE;
+=09return 0;
 }
=20
-static int nfs_get_option_ul_bound(substring_t args[], unsigned long *opti=
on,
-=09=09unsigned long l_bound, unsigned long u_bound)
+static int nfs_get_option_us_bound(struct nfs_fs_context *ctx,
+=09=09=09=09   substring_t args[], unsigned short *option,
+=09=09=09=09   unsigned short l_bound,
+=09=09=09=09   unsigned short u_bound)
 {
 =09int ret;
=20
-=09ret =3D nfs_get_option_ul(args, option);
-=09if (ret !=3D 0)
+=09match_strlcpy(ctx->buf, args, sizeof(ctx->buf));
+=09ret =3D kstrtou16(ctx->buf, 10, option);
+=09if (ret < 0)
 =09=09return ret;
 =09if (*option < l_bound || *option > u_bound)
 =09=09return -ERANGE;
@@ -501,7 +512,6 @@ static int nfs_get_option_ul_bound(substring_t args[], =
unsigned long *option,
 static int nfs_fs_context_parse_option(struct nfs_fs_context *ctx, char *p=
)
 {
 =09substring_t args[MAX_OPT_ARGS];
-=09unsigned long option;
 =09char *string;
 =09int token, rc;
=20
@@ -609,86 +619,70 @@ static int nfs_fs_context_parse_option(struct nfs_fs_=
context *ctx, char *p)
 =09=09 * options that take numeric values
 =09=09 */
 =09case Opt_port:
-=09=09if (nfs_get_option_ul(args, &option) ||
-=09=09    option > USHRT_MAX)
+=09=09if (nfs_get_option_ui_bound(ctx, args, &ctx->nfs_server.port,
+=09=09=09=09=09    0, USHRT_MAX))
 =09=09=09goto out_invalid_value;
-=09=09ctx->nfs_server.port =3D option;
 =09=09break;
 =09case Opt_rsize:
-=09=09if (nfs_get_option_ul(args, &option))
+=09=09if (nfs_get_option_ui(ctx, args, &ctx->rsize))
 =09=09=09goto out_invalid_value;
-=09=09ctx->rsize =3D option;
 =09=09break;
 =09case Opt_wsize:
-=09=09if (nfs_get_option_ul(args, &option))
+=09=09if (nfs_get_option_ui(ctx, args, &ctx->wsize))
 =09=09=09goto out_invalid_value;
-=09=09ctx->wsize =3D option;
 =09=09break;
 =09case Opt_bsize:
-=09=09if (nfs_get_option_ul(args, &option))
+=09=09if (nfs_get_option_ui(ctx, args, &ctx->bsize))
 =09=09=09goto out_invalid_value;
-=09=09ctx->bsize =3D option;
 =09=09break;
 =09case Opt_timeo:
-=09=09if (nfs_get_option_ul_bound(args, &option, 1, INT_MAX))
+=09=09if (nfs_get_option_ui_bound(ctx, args, &ctx->timeo, 1, INT_MAX))
 =09=09=09goto out_invalid_value;
-=09=09ctx->timeo =3D option;
 =09=09break;
 =09case Opt_retrans:
-=09=09if (nfs_get_option_ul_bound(args, &option, 0, INT_MAX))
+=09=09if (nfs_get_option_ui_bound(ctx, args, &ctx->retrans, 0, INT_MAX))
 =09=09=09goto out_invalid_value;
-=09=09ctx->retrans =3D option;
 =09=09break;
 =09case Opt_acregmin:
-=09=09if (nfs_get_option_ul(args, &option))
+=09=09if (nfs_get_option_ui(ctx, args, &ctx->acregmin))
 =09=09=09goto out_invalid_value;
-=09=09ctx->acregmin =3D option;
 =09=09break;
 =09case Opt_acregmax:
-=09=09if (nfs_get_option_ul(args, &option))
+=09=09if (nfs_get_option_ui(ctx, args, &ctx->acregmax))
 =09=09=09goto out_invalid_value;
-=09=09ctx->acregmax =3D option;
 =09=09break;
 =09case Opt_acdirmin:
-=09=09if (nfs_get_option_ul(args, &option))
+=09=09if (nfs_get_option_ui(ctx, args, &ctx->acdirmin))
 =09=09=09goto out_invalid_value;
-=09=09ctx->acdirmin =3D option;
 =09=09break;
 =09case Opt_acdirmax:
-=09=09if (nfs_get_option_ul(args, &option))
+=09=09if (nfs_get_option_ui(ctx, args, &ctx->acdirmax))
 =09=09=09goto out_invalid_value;
-=09=09ctx->acdirmax =3D option;
 =09=09break;
 =09case Opt_actimeo:
-=09=09if (nfs_get_option_ul(args, &option))
+=09=09if (nfs_get_option_ui(ctx, args, &ctx->acdirmax))
 =09=09=09goto out_invalid_value;
 =09=09ctx->acregmin =3D ctx->acregmax =3D
-=09=09=09ctx->acdirmin =3D ctx->acdirmax =3D option;
+=09=09=09ctx->acdirmin =3D ctx->acdirmax;
 =09=09break;
 =09case Opt_namelen:
-=09=09if (nfs_get_option_ul(args, &option))
+=09=09if (nfs_get_option_ui(ctx, args, &ctx->namlen))
 =09=09=09goto out_invalid_value;
-=09=09ctx->namlen =3D option;
 =09=09break;
 =09case Opt_mountport:
-=09=09if (nfs_get_option_ul(args, &option) ||
-=09=09    option > USHRT_MAX)
+=09=09if (nfs_get_option_ui_bound(ctx, args, &ctx->mount_server.port,
+=09=09=09=09=09    0, USHRT_MAX))
 =09=09=09goto out_invalid_value;
-=09=09ctx->mount_server.port =3D option;
 =09=09break;
 =09case Opt_mountvers:
-=09=09if (nfs_get_option_ul(args, &option) ||
-=09=09    option < NFS_MNT_VERSION ||
-=09=09    option > NFS_MNT3_VERSION)
+=09=09if (nfs_get_option_ui_bound(ctx, args, &ctx->mount_server.version,
+=09=09=09=09=09    NFS_MNT_VERSION, NFS_MNT3_VERSION))
 =09=09=09goto out_invalid_value;
-=09=09ctx->mount_server.version =3D option;
 =09=09break;
 =09case Opt_minorversion:
-=09=09if (nfs_get_option_ul(args, &option))
-=09=09=09goto out_invalid_value;
-=09=09if (option > NFS4_MAX_MINOR_VERSION)
+=09=09if (nfs_get_option_ui_bound(ctx, args, &ctx->minorversion,
+=09=09=09=09=09    0, NFS4_MAX_MINOR_VERSION))
 =09=09=09goto out_invalid_value;
-=09=09ctx->minorversion =3D option;
 =09=09break;
=20
 =09=09/*
@@ -820,9 +814,9 @@ static int nfs_fs_context_parse_option(struct nfs_fs_co=
ntext *ctx, char *p)
 =09=09=09goto out_invalid_address;
 =09=09break;
 =09case Opt_nconnect:
-=09=09if (nfs_get_option_ul_bound(args, &option, 1, NFS_MAX_CONNECTIONS))
+=09=09if (nfs_get_option_us_bound(ctx, args, &ctx->nfs_server.nconnect,
+=09=09=09=09=09    1, NFS_MAX_CONNECTIONS))
 =09=09=09goto out_invalid_value;
-=09=09ctx->nfs_server.nconnect =3D option;
 =09=09break;
 =09case Opt_lookupcache:
 =09=09string =3D match_strdup(args);
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index d0abc7b65cd2..5342f3e4d565 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -122,6 +122,8 @@ struct nfs_fs_context {
=20
 =09void=09=09=09*lsm_opts;
 =09struct net=09=09*net;
+
+=09char=09=09=09buf[32];=09/* Parse buffer */
 };
=20
 /* mount_clnt.c */
--=20
2.17.2