Some security measurements

2 files changed, 16 insertions, 9 deletions

diff --git a/kernel/features/fs.c b/kernel/features/fs.c
index c8ad317..c692aac 100644
--- a/kernel/features/fs.c
+++ b/kernel/features/fs.c
@@ -5,6 +5,7 @@
 #include <fs.h>
 #include <ide.h>
 #include <mem.h>
+#include <mm.h>
 #include <print.h>
 #include <random.h>
 #include <str.h>
@@ -240,11 +241,11 @@ s32 vfs_poll(const char **files)
 	if (!files)
 		return -1;
 
-	for (const char **p = files; *p && **p; p++)
+	for (const char **p = files; memory_user_valid((u32)*p) && *p && **p; p++)
 		if (vfs_ready(*p))
 			return p - files;
 
-	for (const char **p = files; *p && **p; p++)
+	for (const char **p = files; memory_user_valid((u32)*p) && *p && **p; p++)
 		vfs_wait(*p, (u32)vfs_poll);
 
 	return PROC_MAX_WAIT_IDS + 1;
diff --git a/kernel/features/mm.c b/kernel/features/mm.c
index 9eca438..875d752 100644
--- a/kernel/features/mm.c
+++ b/kernel/features/mm.c
@@ -9,7 +9,7 @@
 #include <print.h>
 
 static struct page_dir kernel_dir ALIGNED(PAGE_SIZE) = { 0 };
-static struct page_table kernel_tables[256] ALIGNED(PAGE_SIZE) = { 0 };
+static struct page_table kernel_tables[PAGE_KERNEL_COUNT] ALIGNED(PAGE_SIZE) = { 0 };
 
 /**
  * Lowlevel paging
@@ -233,8 +233,8 @@ struct memory_range virtual_alloc(struct page_dir *dir, struct memory_range pran
 	u32 vaddr = 0;
 	u32 size = 0;
 
-	for (u32 i = (user ? 256 : 1) * PAGE_COUNT; i < (user ? PAGE_COUNT : 256) * PAGE_COUNT;
-	     i++) {
+	for (u32 i = (user ? PAGE_KERNEL_COUNT : 1) * PAGE_COUNT;
+	     i < (user ? PAGE_COUNT : PAGE_KERNEL_COUNT) * PAGE_COUNT; i++) {
 		u32 addr = i * PAGE_SIZE;
 		if (!virtual_present(dir, addr)) {
 			if (size == 0)
@@ -284,7 +284,7 @@ struct page_dir *virtual_create_dir(void)
 
 	memset(dir, 0, sizeof(*dir));
 
-	for (u32 i = 0; i < 256; i++) {
+	for (u32 i = 0; i < PAGE_KERNEL_COUNT; i++) {
 		union page_dir_entry *dir_entry = &dir->entries[i];
 
 		dir_entry->bits.present = 1;
@@ -300,7 +300,7 @@ void virtual_destroy_dir(struct page_dir *dir)
 {
 	assert(dir != &kernel_dir);
 
-	for (u32 i = 256; i < PAGE_COUNT; i++) {
+	for (u32 i = PAGE_KERNEL_COUNT; i < PAGE_COUNT; i++) {
 		union page_dir_entry *dir_entry = &dir->entries[i];
 		if (dir_entry->bits.present) {
 			struct page_table *table =
@@ -358,7 +358,7 @@ err:
 
 void *memory_alloc_identity(struct page_dir *dir, u32 flags)
 {
-	for (u32 i = 1; i < 256 * PAGE_COUNT; i++) {
+	for (u32 i = 1; i < PAGE_KERNEL_COUNT * PAGE_COUNT; i++) {
 		struct memory_range range = memory_range(i * PAGE_SIZE, PAGE_SIZE);
 
 		if (!virtual_present(dir, range.base) && !physical_is_used(range)) {
@@ -411,6 +411,12 @@ void memory_backup_dir(struct page_dir **backup)
 	*backup = dir;
 }
 
+// TODO: Check memory validity more often
+u8 memory_user_valid(u32 addr)
+{
+	return addr / PAGE_SIZE / PAGE_COUNT >= PAGE_KERNEL_COUNT;
+}
+
 struct memory_range memory_range_from(u32 base, u32 size)
 {
 	u32 align = PAGE_SIZE - base % PAGE_SIZE;
@@ -466,7 +472,7 @@ void memory_install(struct mem_info *mem_info, struct vid_info *vid_info)
 		}
 	}
 
-	for (u32 i = 0; i < 256; i++) {
+	for (u32 i = 0; i < PAGE_KERNEL_COUNT; i++) {
 		union page_dir_entry *dir_entry = &kernel_dir.entries[i];
 		dir_entry->bits.present = 1;
 		dir_entry->bits.writable = 1;