linux/tools/perf/util/namespaces.h
Ian Rogers c35ce1d918 perf namespaces: Add reference count checking
Add reference count checking controlled by REFCNT_CHECKING ifdef. The
reference count checking interposes an allocated pointer between the
reference counted struct on a get and frees the pointer on a put.
Accesses after a put cause faults and use after free, missed puts are
caughts as leaks and double puts are double frees.

This checking helped resolve a memory leak and use after free:
https://lore.kernel.org/linux-perf-users/CAP-5=fWZH20L4kv-BwVtGLwR=Em3AOOT+Q4QGivvQuYn5AsPRg@mail.gmail.com/

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Link: https://lore.kernel.org/lkml/20230407230405.2931830-4-irogers@google.com
[ Extracted from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2023-04-17 18:51:57 -03:00

84 lines
1.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
*
* Copyright (C) 2017 Hari Bathini, IBM Corporation
*/
#ifndef __PERF_NAMESPACES_H
#define __PERF_NAMESPACES_H
#include <sys/types.h>
#include <sys/stat.h>
#include <linux/stddef.h>
#include <linux/perf_event.h>
#include <linux/refcount.h>
#include <linux/types.h>
#include <internal/rc_check.h>
#ifndef HAVE_SETNS_SUPPORT
int setns(int fd, int nstype);
#endif
struct perf_record_namespaces;
struct namespaces {
struct list_head list;
u64 end_time;
struct perf_ns_link_info link_info[];
};
struct namespaces *namespaces__new(struct perf_record_namespaces *event);
void namespaces__free(struct namespaces *namespaces);
DECLARE_RC_STRUCT(nsinfo) {
pid_t pid;
pid_t tgid;
pid_t nstgid;
bool need_setns;
bool in_pidns;
char *mntns_path;
refcount_t refcnt;
};
struct nscookie {
int oldns;
int newns;
char *oldcwd;
};
int nsinfo__init(struct nsinfo *nsi);
struct nsinfo *nsinfo__new(pid_t pid);
struct nsinfo *nsinfo__copy(const struct nsinfo *nsi);
struct nsinfo *nsinfo__get(struct nsinfo *nsi);
void nsinfo__put(struct nsinfo *nsi);
bool nsinfo__need_setns(const struct nsinfo *nsi);
void nsinfo__clear_need_setns(struct nsinfo *nsi);
pid_t nsinfo__tgid(const struct nsinfo *nsi);
pid_t nsinfo__nstgid(const struct nsinfo *nsi);
pid_t nsinfo__pid(const struct nsinfo *nsi);
pid_t nsinfo__in_pidns(const struct nsinfo *nsi);
void nsinfo__mountns_enter(struct nsinfo *nsi, struct nscookie *nc);
void nsinfo__mountns_exit(struct nscookie *nc);
char *nsinfo__realpath(const char *path, struct nsinfo *nsi);
int nsinfo__stat(const char *filename, struct stat *st, struct nsinfo *nsi);
bool nsinfo__is_in_root_namespace(void);
static inline void __nsinfo__zput(struct nsinfo **nsip)
{
if (nsip) {
nsinfo__put(*nsip);
*nsip = NULL;
}
}
#define nsinfo__zput(nsi) __nsinfo__zput(&nsi)
const char *perf_ns__name(unsigned int id);
#endif /* __PERF_NAMESPACES_H */