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ppm_fillers.c
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// SPDX-License-Identifier: GPL-2.0-only OR MIT
/*
Copyright (C) 2023 The Falco Authors.
This file is dual licensed under either the MIT or GPL 2. See MIT.txt
or GPL2.txt for full copies of the license.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/compat.h>
#include <linux/cdev.h>
#include <asm/unistd.h>
#include <net/sock.h>
#include <net/af_unix.h>
#include <net/compat.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/fdtable.h>
#include <linux/file.h>
#include <linux/fs_struct.h>
#include <linux/pid_namespace.h>
#include <linux/ptrace.h>
#include <linux/version.h>
#include <linux/module.h>
#include <linux/quota.h>
#include <linux/tty.h>
#include <linux/uaccess.h>
#include <linux/audit.h>
#ifdef CONFIG_CGROUPS
#include <linux/cgroup.h>
#endif
#include <asm/syscall.h>
#include "ppm_ringbuffer.h"
#include "ppm_events_public.h"
#include "ppm_events.h"
#include "ppm.h"
#include "ppm_flag_helpers.h"
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 18, 0)
#include <linux/bpf.h>
#endif
#include "kernel_hacks.h"
#include "systype_compat.h"
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 13, 0)
struct ovl_entry {
struct dentry *__upperdentry;
struct ovl_dir_cache *cache;
union {
struct {
uint64_t version;
const char *redirect;
bool opaque;
bool impure;
bool copying;
};
struct rcu_head rcu;
};
unsigned numlower;
struct path lowerstack[];
};
#endif
#define merge_64(hi, lo) ((((unsigned long long)(hi)) << 32) + ((lo) & 0xffffffffUL))
static enum ppm_overlay ppm_get_overlay_layer(struct file *file);
static inline struct pid_namespace *pid_ns_for_children(struct task_struct *task) {
#if(LINUX_VERSION_CODE < KERNEL_VERSION(3, 11, 0))
return task->nsproxy->pid_ns;
#else
return task->nsproxy->pid_ns_for_children;
#endif
}
/*
* Detect whether the file being referenced is an anonymous file created using memfd_create()
* and is being executed by referencing its file descriptor (fd). This type of file does not
* exist on disk and resides solely in memory, but it is treated as a legitimate file with an
* inode object and other file attributes.
*
**/
static inline uint32_t get_exe_from_memfd(const struct file *exe_file) {
#if defined(CONFIG_MEMFD_CREATE) && CONFIG_MEMFD_CREATE == 1
const char expected_prefix[] = "memfd:";
if(!(exe_file && exe_file->f_path.dentry &&
exe_file->f_path.dentry == exe_file->f_path.dentry->d_parent)) {
return 0;
}
if(strncmp(exe_file->f_path.dentry->d_name.name,
expected_prefix,
sizeof(expected_prefix) - 1) == 0) {
return PPM_EXE_FROM_MEMFD;
}
#endif
return 0;
}
int f_sys_generic(struct event_filler_arguments *args) {
int res;
long table_index = args->syscall_id - SYSCALL_TABLE_ID0;
/*
* name
*/
if(likely(table_index >= 0 && table_index < SYSCALL_TABLE_SIZE)) {
ppm_sc_code sc_code = g_syscall_table[table_index].ppm_sc;
/*
* ID
*/
res = val_to_ring(args, sc_code, 0, false, 0);
CHECK_RES(res);
if(args->event_type == PPME_GENERIC_E) {
/*
* nativeID
*/
res = val_to_ring(args, args->syscall_id, 0, false, 0);
CHECK_RES(res);
}
} else {
ASSERT(false);
res = val_to_ring(args, (uint64_t) "<out of bound>", 0, false, 0);
CHECK_RES(res);
}
return add_sentinel(args);
}
int f_sys_empty(struct event_filler_arguments *args) {
return add_sentinel(args);
}
int f_sys_single(struct event_filler_arguments *args) {
int res;
unsigned long val;
syscall_get_arguments_deprecated(args, 0, 1, &val);
res = val_to_ring(args, val, 0, true, 0);
CHECK_RES(res);
return add_sentinel(args);
}
int f_sys_single_x(struct event_filler_arguments *args) {
int res;
int64_t retval;
retval = (int64_t)(long)syscall_get_return_value(current, args->regs);
res = val_to_ring(args, retval, 0, false, 0);
CHECK_RES(res);
return add_sentinel(args);
}
int f_sys_fstat_e(struct event_filler_arguments *args) {
int res = 0;
unsigned long val = 0;
int32_t fd = 0;
/* Parameter 1: fd (type: PT_FD) */
syscall_get_arguments_deprecated(args, 0, 1, &val);
fd = (int32_t)val;
res = val_to_ring(args, (int64_t)fd, 0, false, 0);
CHECK_RES(res);
return add_sentinel(args);
}
static inline void get_ino_from_fd(int64_t fd, uint64_t *ino) {
struct files_struct *files;
struct fdtable *fdt;
struct inode *inode;
struct file *file;
if(fd < 0)
return;
files = current->files;
if(unlikely(!files))
return;
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
if(unlikely(fd > fdt->max_fds))
goto out_unlock;
file = fdt->fd[fd];
if(unlikely(!file))
goto out_unlock;
inode = file_inode(file);
if(unlikely(!inode))
goto out_unlock;
*ino = inode->i_ino;
out_unlock:
spin_unlock(&files->file_lock);
return;
}
static inline void get_dev_ino_overlay_from_fd(int64_t fd,
uint32_t *dev,
uint64_t *ino,
enum ppm_overlay *ol) {
struct files_struct *files;
struct fdtable *fdt;
struct inode *inode;
struct super_block *sb;
struct file *file;
if(fd < 0)
return;
files = current->files;
if(unlikely(!files))
return;
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
if(unlikely(fd > fdt->max_fds))
goto out_unlock;
file = fdt->fd[fd];
if(unlikely(!file))
goto out_unlock;
*ol = ppm_get_overlay_layer(file);
inode = file_inode(file);
if(unlikely(!inode))
goto out_unlock;
*ino = inode->i_ino;
sb = inode->i_sb;
if(unlikely(!sb))
goto out_unlock;
*dev = new_encode_dev(sb->s_dev);
out_unlock:
spin_unlock(&files->file_lock);
return;
}
static inline void get_fd_fmode_created(int64_t fd, unsigned long *flags) {
/* FMODE_CREATED flag was introduced in kernel 4.19 and it's not present in earlier versions */
#if LINUX_VERSION_CODE > KERNEL_VERSION(4, 19, 0)
struct files_struct *files;
struct fdtable *fdt;
struct file *file;
if(fd < 0)
return;
files = current->files;
if(unlikely(!files))
return;
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
if(unlikely(fd > fdt->max_fds))
goto out_unlock;
file = fdt->fd[fd];
if(unlikely(!file))
goto out_unlock;
if(file->f_mode & FMODE_CREATED)
*flags |= PPM_O_F_CREATED;
out_unlock:
spin_unlock(&files->file_lock);
#endif
return;
}
int f_sys_open_e(struct event_filler_arguments *args) {
unsigned long val;
unsigned long flags;
unsigned long modes;
int res;
/*
* name
*/
syscall_get_arguments_deprecated(args, 0, 1, &val);
res = val_to_ring(args, val, 0, true, 0);
CHECK_RES(res);
/*
* Flags
* Note that we convert them into the ppm portable representation before pushing them to the
* ring
*/
syscall_get_arguments_deprecated(args, 1, 1, &flags);
res = val_to_ring(args, open_flags_to_scap(flags), 0, false, 0);
CHECK_RES(res);
/*
* mode
*/
syscall_get_arguments_deprecated(args, 2, 1, &modes);
res = val_to_ring(args, open_modes_to_scap(flags, modes), 0, false, 0);
CHECK_RES(res);
return add_sentinel(args);
}
int f_sys_open_x(struct event_filler_arguments *args) {
unsigned long val;
unsigned long flags;
unsigned long scap_flags;
unsigned long modes;
uint32_t dev = 0;
uint64_t ino = 0;
int res;
int64_t retval;
enum ppm_overlay ol;
/*
* fd
*/
retval = (int64_t)syscall_get_return_value(current, args->regs);
res = val_to_ring(args, retval, 0, false, 0);
CHECK_RES(res);
/*
* name
*/
syscall_get_arguments_deprecated(args, 0, 1, &val);
res = val_to_ring(args, val, 0, true, 0);
CHECK_RES(res);
get_dev_ino_overlay_from_fd(retval, &dev, &ino, &ol);
/*
* Flags
* Note that we convert them into the ppm portable representation before pushing them to the
* ring
*/
syscall_get_arguments_deprecated(args, 1, 1, &flags);
scap_flags = open_flags_to_scap(flags);
/* update scap flags if file is created */
get_fd_fmode_created(retval, &scap_flags);
if(ol == PPM_OVERLAY_UPPER) {
scap_flags |= PPM_FD_UPPER_LAYER;
} else if(ol == PPM_OVERLAY_LOWER) {
scap_flags |= PPM_FD_LOWER_LAYER;
}
res = val_to_ring(args, scap_flags, 0, false, 0);
CHECK_RES(res);
/*
* mode
*/
syscall_get_arguments_deprecated(args, 2, 1, &modes);
res = val_to_ring(args, open_modes_to_scap(flags, modes), 0, false, 0);
CHECK_RES(res);
/*
* dev
*/
res = val_to_ring(args, dev, 0, false, 0);
CHECK_RES(res);
/*
* ino
*/
res = val_to_ring(args, ino, 0, false, 0);
CHECK_RES(res);
return add_sentinel(args);
}
int f_sys_read_e(struct event_filler_arguments *args) {
unsigned long val = 0;
int res = 0;
int32_t fd = 0;
/* Parameter 1: fd (type: PT_FD) */
syscall_get_arguments_deprecated(args, 0, 1, &val);
fd = (int32_t)val;
res = val_to_ring(args, (int64_t)fd, 0, false, 0);
CHECK_RES(res);
/* Parameter 2: size (type: PT_UINT32) */
syscall_get_arguments_deprecated(args, 2, 1, &val);
res = val_to_ring(args, val, 0, false, 0);
CHECK_RES(res);
return add_sentinel(args);
}
int f_sys_read_x(struct event_filler_arguments *args) {
unsigned long val;
int res;
int64_t retval;
unsigned long bufsize;
/*
* Retrieve the FD. It will be used for dynamic snaplen calculation.
*/
syscall_get_arguments_deprecated(args, 0, 1, &val);
args->fd = (int)val;
/*
* res
*/
retval = (int64_t)(long)syscall_get_return_value(current, args->regs);
res = val_to_ring(args, retval, 0, false, 0);
CHECK_RES(res);
/*
* data
*/
if(retval < 0) {
/*
* The operation failed, return an empty buffer
*/
val = 0;
bufsize = 0;
} else {
syscall_get_arguments_deprecated(args, 1, 1, &val);
/*
* The return value can be lower than the value provided by the user,
* and we take that into account.
*/
bufsize = retval;
}
/*
* Copy the buffer
*/
args->enforce_snaplen = true;
res = val_to_ring(args, val, bufsize, true, 0);
CHECK_RES(res);
return add_sentinel(args);
}
int f_sys_write_e(struct event_filler_arguments *args) {
unsigned long val = 0;
int res = 0;
int32_t fd = 0;
/* Parameter 1: fd (type: PT_FD) */
syscall_get_arguments_deprecated(args, 0, 1, &val);
fd = (int32_t)val;
res = val_to_ring(args, (int64_t)fd, 0, false, 0);
CHECK_RES(res);
/* Parameter 2: size (type: PT_UINT32) */
syscall_get_arguments_deprecated(args, 2, 1, &val);
res = val_to_ring(args, val, 0, false, 0);
CHECK_RES(res);
return add_sentinel(args);
}
int f_sys_write_x(struct event_filler_arguments *args) {
unsigned long val;
int res;
int64_t retval;
unsigned long bufsize;
/*
* Retrieve the FD. It will be used for dynamic snaplen calculation.
*/
syscall_get_arguments_deprecated(args, 0, 1, &val);
args->fd = (int)val;
/* Parameter 1: res (type: PT_ERRNO) */
retval = (int64_t)(long)syscall_get_return_value(current, args->regs);
res = val_to_ring(args, retval, 0, false, 0);
CHECK_RES(res);
/* Parameter 2: data (type: PT_BYTEBUF) */
/* Get the size from userspace paramater */
syscall_get_arguments_deprecated(args, 2, 1, &val);
bufsize = retval > 0 ? retval : val;
syscall_get_arguments_deprecated(args, 1, 1, &val);
args->enforce_snaplen = true;
res = val_to_ring(args, val, bufsize, true, 0);
CHECK_RES(res);
return add_sentinel(args);
}
/*
* get_mm_exe_file is only exported in some kernel versions
*/
static struct file *ppm_get_mm_exe_file(struct mm_struct *mm) {
struct file *exe_file;
/*
* The following if/else preprocessor directive is to cover for that change:
* https://github.com/torvalds/linux/commit/90f31d0ea88880f780574f3d0bb1a227c4c66ca3#diff-e37b5cb4c23f6ab27741c60ec48674eff0268624a228c9a1cddddb9e4ee2922dL709
* That was introduced in linux 4.1, but it's backported in some distro kernels.
* Luckily enough, `get_file_rcu` is a define, so we can check for it and use
* the safer version.
*/
#if defined(get_file_rcu)
rcu_read_lock();
exe_file = rcu_dereference(mm->exe_file);
if(exe_file && !get_file_rcu(exe_file))
exe_file = NULL;
rcu_read_unlock();
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(6, 7, 0)
// Since linux 6.7.0, `get_file_rcu` is no more a define and takes a double pointer parameter.
// See https://github.com/torvalds/linux/commit/0ede61d8589cc2d93aa78230d74ac58b5b8d0244.
rcu_read_lock();
exe_file = get_file_rcu(&mm->exe_file);
rcu_read_unlock();
#else
/* We need mmap_sem to protect against races with removal of
* VM_EXECUTABLE vmas */
down_read(&mm->mmap_sem);
exe_file = mm->exe_file;
if(exe_file)
get_file(exe_file);
up_read(&mm->mmap_sem);
#endif
return exe_file;
}
/*
* get_mm_counter was not inline and exported between 3.0 and 3.4
* https://github.com/torvalds/linux/commit/69c978232aaa99476f9bd002c2a29a84fa3779b5
* Hence the crap in these two functions
*/
static unsigned long ppm_get_mm_counter(struct mm_struct *mm, int member) {
long val = 0;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 4, 0)
val = get_mm_counter(mm, member);
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 34)
val = atomic_long_read(&mm->rss_stat.count[member]);
if(val < 0)
val = 0;
#endif
return val;
}
static unsigned long ppm_get_mm_swap(struct mm_struct *mm) {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 34)
return ppm_get_mm_counter(mm, MM_SWAPENTS);
#endif
return 0;
}
static unsigned long ppm_get_mm_rss(struct mm_struct *mm) {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 4, 0)
return get_mm_rss(mm);
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 34)
return ppm_get_mm_counter(mm, MM_FILEPAGES) + ppm_get_mm_counter(mm, MM_ANONPAGES);
#else
return get_mm_rss(mm);
#endif
return 0;
}
#ifdef CONFIG_CGROUPS
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 34)
static int ppm_cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) {
char *start;
struct dentry *dentry = rcu_dereference(cgrp->dentry);
if(!dentry) {
/*
* Inactive subsystems have no dentry for their root
* cgroup
*/
strcpy(buf, "/");
return 0;
}
start = buf + buflen;
*--start = '\0';
for(;;) {
int len = dentry->d_name.len;
start -= len;
if(start < buf)
return -ENAMETOOLONG;
memcpy(start, cgrp->dentry->d_name.name, len);
cgrp = cgrp->parent;
if(!cgrp)
break;
dentry = rcu_dereference(cgrp->dentry);
if(!cgrp->parent)
continue;
if(--start < buf)
return -ENAMETOOLONG;
*start = '/';
}
memmove(buf, start, buf + buflen - start);
return 0;
}
#endif
static int append_cgroup(const char *subsys_name, int subsys_id, char *buf, int *available) {
int pathlen;
int subsys_len;
char *path;
#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 15, 0) || LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)
int res;
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 12, 0)
struct cgroup_subsys_state *css = task_css(current, subsys_id);
#else
struct cgroup_subsys_state *css = task_subsys_state(current, subsys_id);
#endif
if(!css) {
ASSERT(false);
return 1;
}
if(!css->cgroup) {
ASSERT(false);
return 1;
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 9, 0)
// According to
// https://github.com/torvalds/linux/commit/4c737b41de7f4eef2a593803bad1b918dd718b10 cgroup_path
// now returns an int again
res = cgroup_path(css->cgroup, buf, *available);
if(res < 0) {
ASSERT(false);
path = "NA";
} else {
path = buf;
}
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(3, 15, 0)
path = cgroup_path(css->cgroup, buf, *available);
if(!path) {
ASSERT(false);
path = "NA";
}
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 34)
res = cgroup_path(css->cgroup, buf, *available);
if(res < 0) {
ASSERT(false);
path = "NA";
} else {
path = buf;
}
#else
res = ppm_cgroup_path(css->cgroup, buf, *available);
if(res < 0) {
ASSERT(false);
path = "NA";
} else {
path = buf;
}
#endif
pathlen = strlen(path);
subsys_len = strlen(subsys_name);
if(subsys_len + 1 + pathlen + 1 > *available)
return 1;
memmove(buf + subsys_len + 1, path, pathlen);
memcpy(buf, subsys_name, subsys_len);
buf += subsys_len;
*buf++ = '=';
buf += pathlen;
*buf++ = 0;
*available -= (subsys_len + 1 + pathlen + 1);
return 0;
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 15, 0)
#define SUBSYS(_x) \
if(append_cgroup(#_x, \
_x##_cgrp_id, \
args->str_storage + STR_STORAGE_SIZE - available, \
&available)) \
goto cgroups_error;
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(3, 10, 0)
#define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option)
#define SUBSYS(_x) \
if(append_cgroup(#_x, \
_x##_subsys_id, \
args->str_storage + STR_STORAGE_SIZE - available, \
&available)) \
goto cgroups_error;
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(3, 7, 0)
#define IS_SUBSYS_ENABLED(option) IS_ENABLED(option)
#define SUBSYS(_x) \
if(append_cgroup(#_x, \
_x##_subsys_id, \
args->str_storage + STR_STORAGE_SIZE - available, \
&available)) \
goto cgroups_error;
#else
#define SUBSYS(_x) \
if(append_cgroup(#_x, \
_x##_subsys_id, \
args->str_storage + STR_STORAGE_SIZE - available, \
&available)) \
goto cgroups_error;
#endif
#endif
/* Takes in a NULL-terminated array of pointers to strings in userspace, and
* concatenates them to a single \0-separated string. Return the length of these
* strings with the final '\0' included.
*/
static int accumulate_argv_or_env(const void __user *argv, char *str_storage) {
int len = 0;
int ret = 0;
const char __user *p = NULL;
for(;;) {
if(argv == NULL)
break;
if(unlikely(ppm_get_user(p, argv))) {
/* We return what we read until now */
break;
}
if(p == NULL)
break;
/* ppm_strncpy_from_user includes the trailing \0 */
ret = ppm_strncpy_from_user(&str_storage[len], p, STR_STORAGE_SIZE - len);
if(ret < 0) {
/* We ignore the failed read. We will try to read from the same position in
* the next iteration.
*/
ret = 0;
}
len += ret;
if(len >= STR_STORAGE_SIZE) {
len = STR_STORAGE_SIZE;
break;
}
argv += sizeof(argv);
}
if(len > 0) {
str_storage[len - 1] = '\0';
} else {
str_storage[0] = '\0';
}
return len;
}
#ifdef CONFIG_COMPAT
/* compat version that deals correctly with 32bits pointers of argv */
static int compat_accumulate_argv_or_env(compat_uptr_t argv, char *str_storage) {
int len = 0;
int ret = 0;
const char __user *p = NULL;
for(;;) {
compat_uptr_t compat_p = 0;
if(compat_ptr(argv) == NULL)
break;
if(unlikely(ppm_get_user(compat_p, compat_ptr(argv)))) {
/* We return what we read until now */
break;
}
p = compat_ptr(compat_p);
if(p == NULL)
break;
/* ppm_strncpy_from_user includes the trailing \0 */
ret = ppm_strncpy_from_user(&str_storage[len], p, STR_STORAGE_SIZE - len);
if(ret < 0) {
/* We ignore the failed read. We will try to read from the same position in
* the next iteration.
*/
ret = 0;
}
len += ret;
if(len >= STR_STORAGE_SIZE) {
len = STR_STORAGE_SIZE;
break;
}
argv += sizeof(argv);
}
if(len > 0) {
str_storage[len - 1] = '\0';
} else {
str_storage[0] = '\0';
}
return len;
}
#endif
static uint32_t ppm_get_tty(void) {
/* Locking of the signal structures seems too complicated across
* multiple kernel versions to get it right, so simply do protected
* memory accesses, and in the worst case we get some garbage,
* which is not the end of the world. In the vast majority of accesses,
* we'll be just fine.
*/
struct signal_struct *sig;
struct tty_struct *tty;
struct tty_driver *driver;
int major;
int minor_start;
int index;
uint32_t tty_nr = 0;
sig = current->signal;
if(!sig)
return 0;
if(unlikely(copy_from_kernel_nofault(&tty, &sig->tty, sizeof(tty))))
return 0;
if(!tty)
return 0;
if(unlikely(copy_from_kernel_nofault(&index, &tty->index, sizeof(index))))
return 0;
if(unlikely(copy_from_kernel_nofault(&driver, &tty->driver, sizeof(driver))))
return 0;
if(!driver)
return 0;
if(unlikely(copy_from_kernel_nofault(&major, &driver->major, sizeof(major))))
return 0;
if(unlikely(copy_from_kernel_nofault(&minor_start, &driver->minor_start, sizeof(minor_start))))
return 0;
tty_nr = new_encode_dev(MKDEV(major, minor_start) + index);
return tty_nr;
}
static enum ppm_overlay ppm_get_overlay_layer(struct file *file) {
// 3.18 is the Kernel version where overlayfs was introduced
#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 18, 0)
return PPM_NOT_OVERLAY_FS;
#else
struct dentry *dentry = NULL;
struct super_block *sb = NULL;
struct dentry *upper_dentry = NULL;
struct inode *upper_ino = NULL;
if(!file) {
return PPM_NOT_OVERLAY_FS;
}
dentry = file->f_path.dentry;
if(!dentry) {
return PPM_NOT_OVERLAY_FS;
}
sb = dentry->d_sb;
if(!sb) {
return PPM_NOT_OVERLAY_FS;
}
if(sb->s_magic != PPM_OVERLAYFS_SUPER_MAGIC) {
return PPM_NOT_OVERLAY_FS;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 13, 0)
// New scope to avoid `ISO C90 forbids mixed declarations and code` error
{
struct ovl_entry *oe = (struct ovl_entry *)(dentry->d_fsdata);
if(!oe) {
return PPM_OVERLAY_LOWER;
}
upper_dentry = oe->__upperdentry;
}
#else
{
char *vfs_inode = (char *)dentry->d_inode;
if(!vfs_inode) {
return PPM_OVERLAY_LOWER;
}
// Pointer arithmetics due to unexported ovl_inode struct
// warning: this works if and only if the dentry pointer
// is placed right after the inode struct
// todo!: this is dangerous we should find a way to check it at compile time.
upper_dentry = *(struct dentry **)(vfs_inode + sizeof(struct inode));
}
#endif // LINUX_VERSION_CODE < KERNEL_VERSION(4, 13, 0)
if(!upper_dentry) {
return PPM_OVERLAY_LOWER;
}
upper_ino = upper_dentry->d_inode;
if(!upper_ino) {
return PPM_OVERLAY_LOWER;
}
if(upper_ino->i_ino != 0) {
return PPM_OVERLAY_UPPER;
}
return PPM_OVERLAY_LOWER;
#endif // LINUX_VERSION_CODE < KERNEL_VERSION(3, 18, 0)
}
static inline int push_pgid(struct event_filler_arguments *args) {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 24)
// task_pgrp_nr_ns has been introduced in 2.6.24
// https://elixir.bootlin.com/linux/v2.6.24/source/kernel/pid.c#L458
return val_to_ring(args, task_pgrp_nr_ns(current, &init_pid_ns), 0, false, 0);
#else
// https://elixir.bootlin.com/linux/v2.6.23/source/kernel/sys.c#L1543
// we don't have the concept of pid namespace in this kernel version
return val_to_ring(args, process_group(current), 0, false, 0);
#endif
}
int f_proc_startupdate(struct event_filler_arguments *args) {
unsigned long val = 0;
int res = 0;
unsigned int exe_len = 0; /* the length of the executable string */
int args_len = 0; /*the combined length of the arguments string + executable string */
struct mm_struct *mm = current->mm;
int64_t retval;
int ptid;
long total_vm = 0;
long total_rss = 0;
long swap = 0;
int available = STR_STORAGE_SIZE;
const struct cred *cred;
uint64_t pidns_init_start_time = 0;
#ifdef __NR_clone3
struct clone_args cl_args;
#endif
/*
* Make sure the operation was successful
*/
retval = (int64_t)syscall_get_return_value(current, args->regs);
res = val_to_ring(args, retval, 0, false, 0);
CHECK_RES(res);
if(unlikely(retval < 0 && args->event_type != PPME_SYSCALL_EXECVE_19_X &&
args->event_type != PPME_SYSCALL_EXECVEAT_X)) {
/* The call failed, but this syscall has no exe, args
* anyway, so I report empty ones */
*args->str_storage = 0;
/*
* exe
*/
res = val_to_ring(args, (uint64_t)(long)args->str_storage, 0, false, 0);
CHECK_RES(res);
/*
* Args
*/
res = val_to_ring(args, (int64_t)(long)args->str_storage, 0, false, 0);
CHECK_RES(res);
} else {
if(likely(retval >= 0)) {
/*
* The call succeeded. Get exe, args from the current
* process; put one \0-separated exe-args string into
* str_storage
*/
if(unlikely(!mm)) {
args->str_storage[0] = 0;
pr_info("f_proc_startupdate drop, mm=NULL\n");
return PPM_FAILURE_BUG;
}
if(unlikely(!mm->arg_end)) {
args->str_storage[0] = 0;
pr_info("f_proc_startupdate drop, mm->arg_end=NULL\n");