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Groups > linux.kernel > #1665967

[PATCH 22/27] NFS: Add a small buffer in nfs_fs_context to avoid string dup [ver #5]

From David Howells <dhowells@redhat.com>
Newsgroups linux.kernel
Subject [PATCH 22/27] NFS: Add a small buffer in nfs_fs_context to avoid string dup [ver #5]
Date 2017-06-14 17:20 +0200
Message-ID <tSifp-6QJ-57@gated-at.bofh.it> (permalink)
References <tSifn-6QJ-7@gated-at.bofh.it>
Organization Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903

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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>
---

 fs/nfs/fs_context.c |   83 ++++++++++++++++++---------------------------------
 fs/nfs/internal.h   |    2 +
 2 files changed, 32 insertions(+), 53 deletions(-)

diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
index a2ff9c30ff5a..763a09b64971 100644
--- a/fs/nfs/fs_context.c
+++ b/fs/nfs/fs_context.c
@@ -466,27 +466,22 @@ static int nfs_get_option_str(substring_t args[], char **option)
 	return !*option;
 }
 
-static int nfs_get_option_ul(substring_t args[], unsigned long *option)
+static int nfs_get_option_ui(struct nfs_fs_context *ctx,
+			     substring_t args[], unsigned int *option)
 {
-	int rc;
-	char *string;
-
-	string = match_strdup(args);
-	if (string == NULL)
-		return -ENOMEM;
-	rc = kstrtoul(string, 10, option);
-	kfree(string);
-
-	return rc;
+	match_strlcpy(ctx->buf, args, sizeof(ctx->buf));
+	return kstrtouint(ctx->buf, 10, option);
 }
 
-static int nfs_get_option_ul_bound(substring_t args[], unsigned long *option,
-		unsigned long l_bound, unsigned long u_bound)
+static int nfs_get_option_ui_bound(struct nfs_fs_context *ctx,
+				   substring_t args[], unsigned int *option,
+				   unsigned int l_bound, unsigned u_bound)
 {
 	int ret;
 
-	ret = nfs_get_option_ul(args, option);
-	if (ret != 0)
+	match_strlcpy(ctx->buf, args, sizeof(ctx->buf));
+	ret = kstrtouint(ctx->buf, 10, option);
+	if (ret < 0)
 		return ret;
 	if (*option < l_bound || *option > u_bound)
 		return -ERANGE;
@@ -499,7 +494,6 @@ 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)
 {
 	substring_t args[MAX_OPT_ARGS];
-	unsigned long option;
 	char *string;
 	int rc, token;
 
@@ -507,7 +501,6 @@ static int nfs_fs_context_parse_option(struct nfs_fs_context *ctx, char *p)
 
 	token = match_token(p, nfs_mount_option_tokens, args);
 	switch (token) {
-
 		/*
 		 * boolean options:  foo/nofoo
 		 */
@@ -603,86 +596,70 @@ static int nfs_fs_context_parse_option(struct nfs_fs_context *ctx, char *p)
 		 * options that take numeric values
 		 */
 	case Opt_port:
-		if (nfs_get_option_ul(args, &option) ||
-		    option > USHRT_MAX)
+		if (nfs_get_option_ui_bound(ctx, args, &ctx->nfs_server.port,
+					    0, USHRT_MAX))
 			goto out_invalid_value;
-		ctx->nfs_server.port = option;
 		break;
 	case Opt_rsize:
-		if (nfs_get_option_ul(args, &option))
+		if (nfs_get_option_ui(ctx, args, &ctx->rsize))
 			goto out_invalid_value;
-		ctx->rsize = option;
 		break;
 	case Opt_wsize:
-		if (nfs_get_option_ul(args, &option))
+		if (nfs_get_option_ui(ctx, args, &ctx->wsize))
 			goto out_invalid_value;
-		ctx->wsize = option;
 		break;
 	case Opt_bsize:
-		if (nfs_get_option_ul(args, &option))
+		if (nfs_get_option_ui(ctx, args, &ctx->bsize))
 			goto out_invalid_value;
-		ctx->bsize = option;
 		break;
 	case Opt_timeo:
-		if (nfs_get_option_ul_bound(args, &option, 1, INT_MAX))
+		if (nfs_get_option_ui_bound(ctx, args, &ctx->timeo, 1, INT_MAX))
 			goto out_invalid_value;
-		ctx->timeo = option;
 		break;
 	case Opt_retrans:
-		if (nfs_get_option_ul_bound(args, &option, 0, INT_MAX))
+		if (nfs_get_option_ui_bound(ctx, args, &ctx->retrans, 0, INT_MAX))
 			goto out_invalid_value;
-		ctx->retrans = option;
 		break;
 	case Opt_acregmin:
-		if (nfs_get_option_ul(args, &option))
+		if (nfs_get_option_ui(ctx, args, &ctx->acregmin))
 			goto out_invalid_value;
-		ctx->acregmin = option;
 		break;
 	case Opt_acregmax:
-		if (nfs_get_option_ul(args, &option))
+		if (nfs_get_option_ui(ctx, args, &ctx->acregmax))
 			goto out_invalid_value;
-		ctx->acregmax = option;
 		break;
 	case Opt_acdirmin:
-		if (nfs_get_option_ul(args, &option))
+		if (nfs_get_option_ui(ctx, args, &ctx->acdirmin))
 			goto out_invalid_value;
-		ctx->acdirmin = option;
 		break;
 	case Opt_acdirmax:
-		if (nfs_get_option_ul(args, &option))
+		if (nfs_get_option_ui(ctx, args, &ctx->acdirmax))
 			goto out_invalid_value;
-		ctx->acdirmax = option;
 		break;
 	case Opt_actimeo:
-		if (nfs_get_option_ul(args, &option))
+		if (nfs_get_option_ui(ctx, args, &ctx->acdirmax))
 			goto out_invalid_value;
 		ctx->acregmin = ctx->acregmax =
-			ctx->acdirmin = ctx->acdirmax = option;
+			ctx->acdirmin = ctx->acdirmax;
 		break;
 	case Opt_namelen:
-		if (nfs_get_option_ul(args, &option))
+		if (nfs_get_option_ui(ctx, args, &ctx->namlen))
 			goto out_invalid_value;
-		ctx->namlen = option;
 		break;
 	case Opt_mountport:
-		if (nfs_get_option_ul(args, &option) ||
-		    option > USHRT_MAX)
+		if (nfs_get_option_ui_bound(ctx, args, &ctx->mount_server.port,
+					    0, USHRT_MAX))
 			goto out_invalid_value;
-		ctx->mount_server.port = option;
 		break;
 	case Opt_mountvers:
-		if (nfs_get_option_ul(args, &option) ||
-		    option < NFS_MNT_VERSION ||
-		    option > NFS_MNT3_VERSION)
+		if (nfs_get_option_ui_bound(ctx, args, &ctx->mount_server.version,
+					    NFS_MNT_VERSION, NFS_MNT3_VERSION))
 			goto out_invalid_value;
-		ctx->mount_server.version = option;
 		break;
 	case Opt_minorversion:
-		if (nfs_get_option_ul(args, &option))
-			goto out_invalid_value;
-		if (option > NFS4_MAX_MINOR_VERSION)
+		if (nfs_get_option_ui_bound(ctx, args, &ctx->minorversion,
+					    0, NFS4_MAX_MINOR_VERSION))
 			goto out_invalid_value;
-		ctx->minorversion = option;
 		break;
 
 		/*
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index fab0fca9e0ef..1c5404d846cc 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -125,6 +125,8 @@ struct nfs_fs_context {
 
 	struct security_mnt_opts lsm_opts;
 	struct net		*net;
+
+	char			buf[32];	/* Parse buffer */
 };
 
 /* mount_clnt.c */

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Thread

[RFC][PATCH 00/27] VFS: Introduce filesystem context [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 11/27] VFS: Remove unused code after filesystem context  changes [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 20/27] NFS: Split nfs_parse_mount_options() [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 03/27] VFS: Make get_mnt_ns() return the namespace [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
    Re: [PATCH 03/27] VFS: Make get_mnt_ns() return the namespace [ver  #5] Al Viro <viro@ZenIV.linux.org.uk> - 2017-06-15 11:20 +0200
  [PATCH 27/27] kernfs, sysfs, cgroup: Support fs_context [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
    Re: [PATCH 27/27] kernfs, sysfs, cgroup: Support fs_context [ver #5] Tejun Heo <tj@kernel.org> - 2017-06-14 20:00 +0200
    Re: [PATCH 27/27] ... and the intel_rdt driver David Howells <dhowells@redhat.com> - 2017-06-15 00:40 +0200
  [PATCH 26/27] cpuset: Use fs_context [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 16/27] proc: Add fs_context support to procfs [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
    Re: [PATCH 16/27] proc: Add fs_context support to procfs [ver #5] Al Viro <viro@ZenIV.linux.org.uk> - 2017-06-15 12:20 +0200
  [PATCH 01/27] Provide a function to create a NUL-terminated string  from unterminated data [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 09/27] VFS: Add LSM hooks for filesystem context [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 25/27] ipc: Convert mqueue fs to fs_context [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
    Re: [PATCH 25/27] ipc: Convert mqueue fs to fs_context [ver #5] Al Viro <viro@ZenIV.linux.org.uk> - 2017-06-15 12:10 +0200
      Re: [PATCH 25/27] ipc: Convert mqueue fs to fs_context [ver #5] David Howells <dhowells@redhat.com> - 2017-06-15 16:50 +0200
  [PATCH 23/27] NFS: Do some tidying of the parsing code [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 22/27] NFS: Add a small buffer in nfs_fs_context to avoid  string dup [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 14/27] VFS: Add a sample program for fsopen/fsmount [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 02/27] VFS: Clean up whitespace in fs/namespace.c and  fs/super.c [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 04/27] VFS: Make get_filesystem() return the affected  filesystem [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 18/27] NFS: Constify mount argument match tables [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:20 +0200
  [PATCH 05/27] VFS: Provide empty name qstr [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:30 +0200
  [PATCH 15/27] procfs: Move proc_fill_super() to fs/proc/root.c [ver  #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:30 +0200
  [PATCH 08/27] VFS: Introduce the structs and doc for a filesystem  context [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:30 +0200
    Re: [PATCH 08/27] VFS: Introduce the structs and doc for a filesystem  context [ver #5] Randy Dunlap <rdunlap@infradead.org> - 2017-06-14 20:10 +0200
      Updated docs David Howells <dhowells@redhat.com> - 2017-06-15 01:00 +0200
        Re: Updated docs Randy Dunlap <rdunlap@infradead.org> - 2017-06-15 04:00 +0200
    Re: [PATCH 08/27] VFS: Introduce the structs and doc for a filesystem  context [ver #5] Casey Schaufler <casey@schaufler-ca.com> - 2017-06-14 22:10 +0200
      Re: [PATCH 08/27] VFS: Introduce the structs and doc for a filesystem context [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 22:50 +0200
        Re: [PATCH 08/27] VFS: Introduce the structs and doc for a filesystem  context [ver #5] Casey Schaufler <casey@schaufler-ca.com> - 2017-06-14 23:00 +0200
          Re: [PATCH 08/27] VFS: Introduce the structs and doc for a  filesystem context [ver #5] Theodore Ts'o <tytso@mit.edu> - 2017-06-17 12:00 +0200
            Re: [PATCH 08/27] VFS: Introduce the structs and doc for a filesystem context [ver #5] David Howells <dhowells@redhat.com> - 2017-06-17 16:20 +0200
              Re: [PATCH 08/27] VFS: Introduce the structs and doc for a  filesystem context [ver #5] Jeff Layton <jlayton@redhat.com> - 2017-06-17 17:00 +0200
                Re: [PATCH 08/27] VFS: Introduce the structs and doc for a filesystem  context [ver #5] Randy Dunlap <rdunlap@infradead.org> - 2017-06-17 17:20 +0200
                Re: [PATCH 08/27] VFS: Introduce the structs and doc for a filesystem context [ver #5] David Howells <dhowells@redhat.com> - 2017-06-19 09:50 +0200
  [PATCH 21/27] NFS: Deindent nfs_fs_context_parse_option() [ver #5] David Howells <dhowells@redhat.com> - 2017-06-14 17:30 +0200
  Re: [PATCH 07/27] VFS: Differentiate mount flags (MS_*) from  internal superblock flags [ver #5] Al Viro <viro@ZenIV.linux.org.uk> - 2017-06-15 11:50 +0200
    Re: [PATCH 07/27] VFS: Differentiate mount flags (MS_*) from  internal superblock flags [ver #5] Christoph Hellwig <hch@infradead.org> - 2017-06-16 11:10 +0200
      Re: [PATCH 07/27] VFS: Differentiate mount flags (MS_*) from internal superblock flags [ver #5] David Howells <dhowells@redhat.com> - 2017-06-16 17:00 +0200
        Re: [PATCH 07/27] VFS: Differentiate mount flags (MS_*) from  internal superblock flags [ver #5] Christoph Hellwig <hch@infradead.org> - 2017-06-16 18:00 +0200
          Re: [PATCH 07/27] VFS: Differentiate mount flags (MS_*) from internal superblock flags [ver #5] David Howells <dhowells@redhat.com> - 2017-06-16 18:00 +0200

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