qemu-e2k/include/qemu/option.h
Daniel P. Berrangé 950c4e6c94 opts: don't silently truncate long option values
The existing QemuOpts parsing code uses a fixed size 1024 byte buffer
for storing the option values. If a value exceeded this size it was
silently truncated and no error reported to the user. Long option values
is not a common scenario, but it is conceivable that they will happen.
eg if the user has a very deeply nested filesystem it would be possible
to come up with a disk path that was > 1024 bytes. Most of the time if
such data was silently truncated, the user would get an error about
opening a non-existant disk. If they're unlucky though, QEMU might use a
completely different disk image from another VM, which could be
considered a security issue. Another example program was in using the
-smbios command line arg with very large data blobs. In this case the
silent truncation will be providing semantically incorrect data to the
guest OS for SMBIOS tables.

If the operating system didn't limit the user's argv when spawning QEMU,
the code should honour whatever length arguments were given without
imposing its own length restrictions. This patch thus changes the code
to use a heap allocated buffer for storing the values during parsing,
lifting the arbitrary length restriction.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20180416111743.8473-4-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2018-05-09 00:13:39 +02:00

143 lines
6.1 KiB
C

/*
* Commandline option parsing functions
*
* Copyright (c) 2003-2008 Fabrice Bellard
* Copyright (c) 2009 Kevin Wolf <kwolf@redhat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef QEMU_OPTION_H
#define QEMU_OPTION_H
#include "qemu/queue.h"
const char *get_opt_value(const char *p, char **value);
void parse_option_size(const char *name, const char *value,
uint64_t *ret, Error **errp);
bool has_help_option(const char *param);
bool is_valid_option_list(const char *param);
enum QemuOptType {
QEMU_OPT_STRING = 0, /* no parsing (use string as-is) */
QEMU_OPT_BOOL, /* on/off */
QEMU_OPT_NUMBER, /* simple number */
QEMU_OPT_SIZE, /* size, accepts (K)ilo, (M)ega, (G)iga, (T)era postfix */
};
typedef struct QemuOptDesc {
const char *name;
enum QemuOptType type;
const char *help;
const char *def_value_str;
} QemuOptDesc;
struct QemuOptsList {
const char *name;
const char *implied_opt_name;
bool merge_lists; /* Merge multiple uses of option into a single list? */
QTAILQ_HEAD(, QemuOpts) head;
QemuOptDesc desc[];
};
const char *qemu_opt_get(QemuOpts *opts, const char *name);
char *qemu_opt_get_del(QemuOpts *opts, const char *name);
/**
* qemu_opt_has_help_opt:
* @opts: options to search for a help request
*
* Check whether the options specified by @opts include one of the
* standard strings which indicate that the user is asking for a
* list of the valid values for a command line option (as defined
* by is_help_option()).
*
* Returns: true if @opts includes 'help' or equivalent.
*/
bool qemu_opt_has_help_opt(QemuOpts *opts);
QemuOpt *qemu_opt_find(QemuOpts *opts, const char *name);
bool qemu_opt_get_bool(QemuOpts *opts, const char *name, bool defval);
uint64_t qemu_opt_get_number(QemuOpts *opts, const char *name, uint64_t defval);
uint64_t qemu_opt_get_size(QemuOpts *opts, const char *name, uint64_t defval);
bool qemu_opt_get_bool_del(QemuOpts *opts, const char *name, bool defval);
uint64_t qemu_opt_get_number_del(QemuOpts *opts, const char *name,
uint64_t defval);
uint64_t qemu_opt_get_size_del(QemuOpts *opts, const char *name,
uint64_t defval);
int qemu_opt_unset(QemuOpts *opts, const char *name);
void qemu_opt_set(QemuOpts *opts, const char *name, const char *value,
Error **errp);
void qemu_opt_set_bool(QemuOpts *opts, const char *name, bool val,
Error **errp);
void qemu_opt_set_number(QemuOpts *opts, const char *name, int64_t val,
Error **errp);
typedef int (*qemu_opt_loopfunc)(void *opaque,
const char *name, const char *value,
Error **errp);
int qemu_opt_foreach(QemuOpts *opts, qemu_opt_loopfunc func, void *opaque,
Error **errp);
typedef struct {
QemuOpts *opts;
QemuOpt *opt;
const char *name;
} QemuOptsIter;
void qemu_opt_iter_init(QemuOptsIter *iter, QemuOpts *opts, const char *name);
const char *qemu_opt_iter_next(QemuOptsIter *iter);
QemuOpts *qemu_opts_find(QemuOptsList *list, const char *id);
QemuOpts *qemu_opts_create(QemuOptsList *list, const char *id,
int fail_if_exists, Error **errp);
void qemu_opts_reset(QemuOptsList *list);
void qemu_opts_loc_restore(QemuOpts *opts);
void qemu_opts_set(QemuOptsList *list, const char *id,
const char *name, const char *value, Error **errp);
const char *qemu_opts_id(QemuOpts *opts);
void qemu_opts_set_id(QemuOpts *opts, char *id);
void qemu_opts_del(QemuOpts *opts);
void qemu_opts_validate(QemuOpts *opts, const QemuOptDesc *desc, Error **errp);
void qemu_opts_do_parse(QemuOpts *opts, const char *params,
const char *firstname, Error **errp);
QemuOpts *qemu_opts_parse_noisily(QemuOptsList *list, const char *params,
bool permit_abbrev);
QemuOpts *qemu_opts_parse(QemuOptsList *list, const char *params,
bool permit_abbrev, Error **errp);
void qemu_opts_set_defaults(QemuOptsList *list, const char *params,
int permit_abbrev);
QemuOpts *qemu_opts_from_qdict(QemuOptsList *list, const QDict *qdict,
Error **errp);
QDict *qemu_opts_to_qdict_filtered(QemuOpts *opts, QDict *qdict,
QemuOptsList *list, bool del);
QDict *qemu_opts_to_qdict(QemuOpts *opts, QDict *qdict);
void qemu_opts_absorb_qdict(QemuOpts *opts, QDict *qdict, Error **errp);
typedef int (*qemu_opts_loopfunc)(void *opaque, QemuOpts *opts, Error **errp);
int qemu_opts_foreach(QemuOptsList *list, qemu_opts_loopfunc func,
void *opaque, Error **errp);
void qemu_opts_print(QemuOpts *opts, const char *sep);
void qemu_opts_print_help(QemuOptsList *list);
void qemu_opts_free(QemuOptsList *list);
QemuOptsList *qemu_opts_append(QemuOptsList *dst, QemuOptsList *list);
QDict *keyval_parse(const char *params, const char *implied_key,
Error **errp);
#endif