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NFS: Add a small buffer in nfs_fs_context to avoid string dup
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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 <[email protected]>
Signed-off-by: Al Viro <[email protected]>
Signed-off-by: Anna Schumaker <[email protected]>
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@dhowells @amschuma-ntap
dhowells authored and amschuma-ntap committed Jan 15, 2020
1 parent cbd071b commit 48be8a6
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Showing 2 changed files with 48 additions and 52 deletions.
98 changes: 46 additions & 52 deletions fs/nfs/fs_context.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -468,27 +468,38 @@ 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;
match_strlcpy(ctx->buf, args, sizeof(ctx->buf));
return kstrtouint(ctx->buf, 10, option);
}

string = match_strdup(args);
if (string == NULL)
return -ENOMEM;
rc = kstrtoul(string, 10, option);
kfree(string);
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;

return rc;
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;
return 0;
}

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_us_bound(struct nfs_fs_context *ctx,
substring_t args[], unsigned short *option,
unsigned short l_bound,
unsigned short u_bound)
{
int ret;

ret = nfs_get_option_ul(args, option);
if (ret != 0)
match_strlcpy(ctx->buf, args, sizeof(ctx->buf));
ret = kstrtou16(ctx->buf, 10, option);
if (ret < 0)
return ret;
if (*option < l_bound || *option > u_bound)
return -ERANGE;
Expand All @@ -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)
{
substring_t args[MAX_OPT_ARGS];
unsigned long option;
char *string;
int token, rc;

Expand Down Expand Up @@ -609,86 +619,70 @@ 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;

/*
Expand Down Expand Up @@ -820,9 +814,9 @@ static int nfs_fs_context_parse_option(struct nfs_fs_context *ctx, char *p)
goto out_invalid_address;
break;
case Opt_nconnect:
if (nfs_get_option_ul_bound(args, &option, 1, NFS_MAX_CONNECTIONS))
if (nfs_get_option_us_bound(ctx, args, &ctx->nfs_server.nconnect,
1, NFS_MAX_CONNECTIONS))
goto out_invalid_value;
ctx->nfs_server.nconnect = option;
break;
case Opt_lookupcache:
string = match_strdup(args);
Expand Down
2 changes: 2 additions & 0 deletions fs/nfs/internal.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -122,6 +122,8 @@ struct nfs_fs_context {

void *lsm_opts;
struct net *net;

char buf[32]; /* Parse buffer */
};

/* mount_clnt.c */
Expand Down

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