[BACKPORT] susfs: Revive SUS_MAP feature

The backport is only to comply with upstream 4.14 task_mmu.c that's why it's different...

It requires a backport commit to prevent kernel panic or system crashing on some apps if using sus_maps:
sidex15/android_kernel_lge_sm8150@4eb32cd

I think there's a better way than this...

Signed-off-by: Yahya Wessam <yahyawessam2002@gmail.com>

Author: sidex15

fs/proc/base.c

@@ -102,6 +102,9 @@
 #include <trace/events/oom.h>
 #include "internal.h"
 #include "fd.h"
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+#include <linux/susfs_def.h>
+#endif
 
 #include "../../lib/kstrtox.h"
 
@@ -841,6 +844,9 @@ static ssize_t mem_rw(struct file *file, char __user *buf,
 	ssize_t copied;
 	char *page;
 	unsigned int flags;
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+	struct vm_area_struct *vma;
+#endif
 
 	if (!mm)
 		return 0;
@@ -857,7 +863,19 @@ static ssize_t mem_rw(struct file *file, char __user *buf,
 
 	while (count > 0) {
 		size_t this_len = min_t(size_t, count, PAGE_SIZE);
-
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+		vma = find_vma(mm, addr);
+		if (vma && vma->vm_file) {
+			struct inode *inode = file_inode(vma->vm_file);
+			if (unlikely(inode->i_mapping->flags & BIT_SUS_MAPS) && susfs_is_current_non_root_user_app_proc()) {
+				if (write) {
+					copied = -EFAULT;
+				} else {
+					copied = -EIO;
+				}
+			}
+		}
+#endif
 		if (write && copy_from_user(page, buf, this_len)) {
 			copied = -EFAULT;
 			break;
@@ -2446,6 +2464,13 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
 				vma = vma->vm_next) {
 			if (!vma->vm_file)
 				continue;
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+			if (unlikely(file_inode(vma->vm_file)->i_mapping->flags & BIT_SUS_MAPS) &&
+				susfs_is_current_non_root_user_app_proc())
+			{
+				continue;
+			}
+#endif
 			if (++pos <= ctx->pos)
 				continue;
 

fs/proc/task_mmu.c

@@ -20,7 +20,7 @@
 #include <linux/uaccess.h>
 #include <linux/mm_inline.h>
 #include <linux/ctype.h>
-#ifdef CONFIG_KSU_SUSFS_SUS_KSTAT
+#if defined(CONFIG_KSU_SUSFS_SUS_KSTAT) || defined(CONFIG_KSU_SUSFS_SUS_MAP)
 #include <linux/susfs_def.h>
 #endif
 
@@ -29,6 +29,10 @@
 #include <asm/tlbflush.h>
 #include "internal.h"
 
+#ifdef CONFIG_KSU_SUSFS_SUS_KSTAT
+extern void susfs_sus_ino_for_show_map_vma(unsigned long ino, dev_t *out_dev, unsigned long *out_ino);
+#endif
+
 void task_mem(struct seq_file *m, struct mm_struct *mm)
 {
 	unsigned long text, lib, swap, anon, file, shmem;
@@ -514,10 +518,6 @@ static void show_vma_header_prefix_fake(struct seq_file *m,
 	seq_putc(m, ' ');
 }
 
-#ifdef CONFIG_KSU_SUSFS_SUS_KSTAT
-extern void susfs_sus_ino_for_show_map_vma(unsigned long ino, dev_t *out_dev, unsigned long *out_ino);
-#endif
-
 static void
 show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
 {
@@ -532,6 +532,24 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
 
 	if (file) {
 		struct inode *inode = file_inode(vma->vm_file);
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+		if (unlikely(inode->i_mapping->flags & BIT_SUS_MAPS) && susfs_is_current_non_root_user_app_proc()) {
+			seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
+			seq_put_hex_ll(m, NULL, vma->vm_start, 8);
+			seq_put_hex_ll(m, "-", vma->vm_end, 8);
+			seq_putc(m, ' ');
+			seq_putc(m, '-');
+			seq_putc(m, '-');
+			seq_putc(m, '-');
+			seq_putc(m, 'p');
+			seq_put_hex_ll(m, " ", pgoff, 8);
+			seq_put_hex_ll(m, " ", MAJOR(dev), 2);
+			seq_put_hex_ll(m, ":", MINOR(dev), 2);
+			seq_put_decimal_ull(m, " ", ino);
+			seq_putc(m, ' ');
+			goto done;
+		}
+#endif
 #ifdef CONFIG_KSU_SUSFS_SUS_KSTAT
 		if (unlikely(inode->i_mapping->flags & BIT_SUS_KSTAT)) {
 			susfs_sus_ino_for_show_map_vma(inode->i_ino, &dev, &ino);
@@ -1090,15 +1108,30 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
 	}
 
 	if (!rollup_mode)
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+		if (vma->vm_file &&
+			unlikely(file_inode(vma->vm_file)->i_mapping->flags & BIT_SUS_MAPS) &&
+			susfs_is_current_non_root_user_app_proc())
+		{
+			seq_printf(m,
+				"Size:           %8lu kB\n"
+				"KernelPageSize: %8lu kB\n"
+				"MMUPageSize:    %8lu kB\n",
+				(vma->vm_end - vma->vm_start) >> 10,
+				4, 4);
+			goto bypass_orig_flow;
+		}
+#endif
 		seq_printf(m,
 			   "Size:           %8lu kB\n"
 			   "KernelPageSize: %8lu kB\n"
 			   "MMUPageSize:    %8lu kB\n",
 			   (vma->vm_end - vma->vm_start) >> 10,
 			   vma_kernel_pagesize(vma) >> 10,
 			   vma_mmu_pagesize(vma) >> 10);
-
-
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+bypass_orig_flow:
+#endif
 	if (!rollup_mode || last_vma)
 		seq_printf(m,
 			   "Rss:            %8lu kB\n"
@@ -1135,9 +1168,22 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
 			   (unsigned long)(mss->pss_locked >> (10 + PSS_SHIFT)));
 
 	if (!rollup_mode) {
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+		if (vma->vm_file &&
+			unlikely(file_inode(vma->vm_file)->i_mapping->flags & BIT_SUS_MAPS) &&
+			susfs_is_current_non_root_user_app_proc())
+		{
+			seq_puts(m, "VmFlags: mr mw me");
+			seq_putc(m, '\n');
+			goto bypass_orig_flow2;
+		}
+#endif
 		arch_show_smap(m, vma);
 		show_smap_vma_flags(m, vma);
 	}
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+bypass_orig_flow2:
+#endif
 	m_cache_vma(m, vma);
 	return ret;
 }
@@ -1772,6 +1818,9 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
 	unsigned long start_vaddr;
 	unsigned long end_vaddr;
 	int ret = 0, copied = 0;
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+	struct vm_area_struct *vma;
+#endif
 
 	if (!mm || !mmget_not_zero(mm))
 		goto out;
@@ -1830,6 +1879,16 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
 		down_read(&mm->mmap_sem);
 		ret = walk_page_range(start_vaddr, end, &pagemap_walk);
 		up_read(&mm->mmap_sem);
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+		vma = find_vma(mm, start_vaddr);
+		if (vma && vma->vm_file) {
+			struct inode *inode = file_inode(vma->vm_file);
+			if (unlikely(inode->i_mapping->flags & BIT_SUS_MAPS) && susfs_is_current_non_root_user_app_proc()) {
+				pm.show_pfn = false;
+				pm.buffer->pme = 0;
+			}
+		}
+#endif
 		start_vaddr = end;
 
 		len = min(count, PM_ENTRY_BYTES * pm.pos);

fs/susfs.c

@@ -1215,6 +1215,41 @@ static int copy_config_to_buf(const char *config_string, char *buf_ptr, size_t *
 	return 0;
 }
 
+/* sus_map */
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+int susfs_add_sus_map(struct st_susfs_sus_map* __user user_info) {
+	struct st_susfs_sus_map info;
+	struct path path;
+	struct inode *inode = NULL;
+	int err = 0;
+
+	err = copy_from_user(&info, user_info, sizeof(info));
+	if (err) {
+		SUSFS_LOGE("failed copying from userspace\n");
+		return err;
+	}
+
+	err = kern_path(info.target_pathname, LOOKUP_FOLLOW, &path);
+	if (err) {
+		SUSFS_LOGE("Failed opening file '%s'\n", info.target_pathname);
+		return err;
+	}
+
+	if (!path.dentry->d_inode) {
+		err = -EINVAL;
+		goto out_path_put_path;
+	}
+	inode = d_inode(path.dentry);
+	spin_lock(&inode->i_lock);
+	set_bit(AS_FLAGS_SUS_MAP, &inode->i_mapping->flags);
+	SUSFS_LOGI("pathname: '%s', is flagged as AS_FLAGS_SUS_MAP\n", info.target_pathname);
+	spin_unlock(&inode->i_lock);
+out_path_put_path:
+	path_put(&path);
+	return err;
+}
+#endif // #ifdef CONFIG_KSU_SUSFS_SUS_MAP
+
 int susfs_get_enabled_features(char __user* buf, size_t bufsize) {
 	char *kbuf = NULL, *buf_ptr = NULL;
 	size_t copied_size = 0;
@@ -1291,6 +1326,11 @@ int susfs_get_enabled_features(char __user* buf, size_t bufsize) {
 	if (err) goto out_kfree_kbuf;
 	buf_ptr = kbuf + copied_size;
 #endif
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+	err = copy_config_to_buf("CONFIG_KSU_SUSFS_SUS_MAP\n", buf_ptr, &copied_size, bufsize);
+	if (err) goto out_kfree_kbuf;
+	buf_ptr = kbuf + copied_size;
+#endif
 #ifdef CONFIG_KSU_SUSFS_HAS_MAGIC_MOUNT
 	err = copy_config_to_buf("CONFIG_KSU_SUSFS_HAS_MAGIC_MOUNT\n", buf_ptr, &copied_size, bufsize);
 	if (err) goto out_kfree_kbuf;

include/linux/susfs.h

@@ -134,6 +134,13 @@ struct st_sus_su {
 };
 #endif
 
+/* sus_map */
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+struct st_susfs_sus_map {
+	char                             target_pathname[SUSFS_MAX_LEN_PATHNAME];
+};
+#endif
+
 /***********************/
 /* FORWARD DECLARATION */
 /***********************/
@@ -192,6 +199,10 @@ struct filename* susfs_get_redirected_path(unsigned long ino);
 int susfs_get_sus_su_working_mode(void);
 int susfs_sus_su(struct st_sus_su* __user user_info);
 #endif
+/* sus_map */
+#ifdef CONFIG_KSU_SUSFS_SUS_MAP
+int susfs_add_sus_map(struct st_susfs_sus_map* __user user_info);
+#endif
 
 int susfs_get_enabled_features(char __user* buf, size_t bufsize);
 void susfs_set_avc_log_spoofing(bool enabled);

include/linux/susfs_def.h

@@ -29,6 +29,7 @@
 #define CMD_SUSFS_IS_SUS_SU_READY 0x555f0
 #define CMD_SUSFS_SUS_SU 0x60000
 #define CMD_SUSFS_ENABLE_AVC_LOG_SPOOFING 0x60010
+#define CMD_SUSFS_ADD_SUS_MAP 0x60020
 
 #define SUSFS_MAX_LEN_PATHNAME 256 // 256 should address many paths already unless you are doing some strange experimental stuff, then set your own desired length
 #define SUSFS_FAKE_CMDLINE_OR_BOOTCONFIG_SIZE 4096
@@ -60,12 +61,14 @@
 #define AS_FLAGS_OPEN_REDIRECT 27
 #define AS_FLAGS_ANDROID_DATA_ROOT_DIR 28
 #define AS_FLAGS_SDCARD_ROOT_DIR 29
+#define AS_FLAGS_SUS_MAP 30
 #define BIT_SUS_PATH BIT(24)
 #define BIT_SUS_MOUNT BIT(25)
 #define BIT_SUS_KSTAT BIT(26)
 #define BIT_OPEN_REDIRECT BIT(27)
 #define BIT_ANDROID_DATA_ROOT_DIR BIT(28)
 #define BIT_ANDROID_SDCARD_ROOT_DIR BIT(29)
+#define BIT_SUS_MAPS BIT(30)
 
 #define ND_STATE_LOOKUP_LAST 32
 #define ND_STATE_OPEN_LAST 64