Added readable/writable checks

3 files changed, 58 insertions, 38 deletions

diff --git a/kernel/features/fs.c b/kernel/features/fs.c
index ded4bf1..76c230e 100644
--- a/kernel/features/fs.c
+++ b/kernel/features/fs.c
@@ -119,10 +119,10 @@ static void vfs_list_mounts()
 
 res vfs_mount(struct device *dev, const char *path)
 {
-	if (!memory_valid(path))
+	if (!memory_readable(path))
 		return -EFAULT;
 
-	if (!memory_valid(dev) || !dev->id)
+	if (!memory_readable(dev) || !dev->id)
 		return -EFAULT;
 
 	if (vfs_mounted(dev, path))
@@ -140,10 +140,10 @@ res vfs_mount(struct device *dev, const char *path)
 
 res vfs_read(const char *path, void *buf, u32 offset, u32 count)
 {
-	if (!memory_valid(path))
+	if (!memory_readable(path))
 		return -EFAULT;
 
-	if (!memory_valid(buf))
+	if (!memory_writable(buf))
 		return -EFAULT;
 
 	struct mount_info *m = vfs_find_mount_info(path);
@@ -168,10 +168,10 @@ res vfs_read(const char *path, void *buf, u32 offset, u32 count)
 
 res vfs_write(const char *path, void *buf, u32 offset, u32 count)
 {
-	if (!memory_valid(path))
+	if (!memory_readable(path))
 		return -EFAULT;
 
-	if (!memory_valid(buf))
+	if (!memory_writable(buf))
 		return -EFAULT;
 
 	struct mount_info *m = vfs_find_mount_info(path);
@@ -196,7 +196,7 @@ res vfs_write(const char *path, void *buf, u32 offset, u32 count)
 
 res vfs_ioctl(const char *path, u32 request, void *arg1, void *arg2, void *arg3)
 {
-	if (!memory_valid(path))
+	if (!memory_readable(path))
 		return -EFAULT;
 
 	struct mount_info *m = vfs_find_mount_info(path);
@@ -218,10 +218,10 @@ res vfs_ioctl(const char *path, u32 request, void *arg1, void *arg2, void *arg3)
 
 res vfs_stat(const char *path, struct stat *buf)
 {
-	if (!memory_valid(path))
+	if (!memory_readable(path))
 		return -EFAULT;
 
-	if (!memory_valid(buf))
+	if (!memory_writable(buf))
 		return -EFAULT;
 
 	struct mount_info *m = vfs_find_mount_info(path);
@@ -243,7 +243,7 @@ res vfs_stat(const char *path, struct stat *buf)
 
 res vfs_block(const char *path, u32 func_ptr)
 {
-	if (!func_ptr || !memory_valid(path))
+	if (!func_ptr || !memory_readable(path))
 		return -EFAULT;
 
 	struct mount_info *m = vfs_find_mount_info(path);
@@ -267,11 +267,11 @@ res vfs_block(const char *path, u32 func_ptr)
 // TODO: Fix page fault when called too often/fast
 res vfs_poll(const char **files)
 {
-	if (!memory_valid(files))
+	if (!memory_readable(files))
 		return -EFAULT;
 
 	stac();
-	for (const char **p = files; *p && memory_valid(*p) && **p; p++) {
+	for (const char **p = files; *p && memory_readable(*p) && **p; p++) {
 		res ready = vfs_ready(*p);
 		clac();
 		if (ready == 1)
@@ -281,7 +281,7 @@ res vfs_poll(const char **files)
 		stac();
 	}
 
-	for (const char **p = files; *p && memory_valid(*p) && **p; p++) {
+	for (const char **p = files; *p && memory_readable(*p) && **p; p++) {
 		vfs_block(*p, (u32)vfs_poll);
 		stac();
 	}
@@ -292,7 +292,7 @@ res vfs_poll(const char **files)
 
 res vfs_ready(const char *path)
 {
-	if (!memory_valid(path))
+	if (!memory_readable(path))
 		return -EFAULT;
 
 	struct mount_info *m = vfs_find_mount_info(path);
diff --git a/kernel/features/load.c b/kernel/features/load.c
index 91954b1..df01e04 100644
--- a/kernel/features/load.c
+++ b/kernel/features/load.c
@@ -11,7 +11,7 @@
 
 res elf_load(const char *name, struct proc *proc)
 {
-	if (!memory_valid(name))
+	if (!memory_readable(name))
 		return -EFAULT;
 
 	stac();
@@ -52,7 +52,7 @@ res elf_load(const char *name, struct proc *proc)
 	    header.version != 1 || header.machine != ELF_MACHINE_386)
 		return -ENOEXEC;
 
-	if (!memory_valid((void *)header.entry))
+	if (!memory_is_user((void *)header.entry))
 		return -ENOEXEC;
 
 	// ASLR
@@ -77,7 +77,7 @@ res elf_load(const char *name, struct proc *proc)
 		if (program.vaddr == 0 || program.type != ELF_PROGRAM_TYPE_LOAD)
 			continue;
 
-		if (!memory_is_user(program.vaddr))
+		if (!memory_is_user((void *)program.vaddr))
 			return -ENOEXEC;
 
 		struct page_dir *prev;
diff --git a/kernel/features/mm.c b/kernel/features/mm.c
index 7baa4ea..466e448 100644
--- a/kernel/features/mm.c
+++ b/kernel/features/mm.c
@@ -199,7 +199,7 @@ void physical_free(struct memory_range range)
 #define PDI(vaddr) ((vaddr) >> 22)
 #define PTI(vaddr) (((vaddr) >> 12) & 0x03ff)
 
-u8 virtual_present(struct page_dir *dir, u32 vaddr)
+union page_table_entry *virtual_entry(struct page_dir *dir, u32 vaddr)
 {
 	u32 pdi = PDI(vaddr);
 	union page_dir_entry *dir_entry = &dir->entries[pdi];
@@ -210,24 +210,35 @@ u8 virtual_present(struct page_dir *dir, u32 vaddr)
 
 	u32 pti = PTI(vaddr);
 	union page_table_entry *table_entry = &table->entries[pti];
+	if (!table_entry->bits.present)
+		return 0;
 
-	return table_entry->bits.present;
+	return table_entry;
 }
 
-u32 virtual_to_physical(struct page_dir *dir, u32 vaddr)
+u8 virtual_present(struct page_dir *dir, u32 vaddr)
 {
-	u32 pdi = PDI(vaddr);
-	union page_dir_entry *dir_entry = &dir->entries[pdi];
-	if (!dir_entry->bits.present)
-		return 0;
+	union page_table_entry *table_entry = virtual_entry(dir, vaddr);
+	return !!table_entry;
+}
 
-	struct page_table *table = (struct page_table *)(dir_entry->bits.address * PAGE_SIZE);
+u8 virtual_user_readable(struct page_dir *dir, u32 vaddr)
+{
+	union page_table_entry *table_entry = virtual_entry(dir, vaddr);
+	return table_entry && table_entry->bits.user;
+}
 
-	u32 pti = PTI(vaddr);
-	union page_table_entry *table_entry = &table->entries[pti];
-	if (!table_entry->bits.present)
-		return 0;
+u8 virtual_user_writable(struct page_dir *dir, u32 vaddr)
+{
+	union page_table_entry *table_entry = virtual_entry(dir, vaddr);
+	return table_entry && table_entry->bits.user && table_entry->bits.writable;
+}
 
+u32 virtual_to_physical(struct page_dir *dir, u32 vaddr)
+{
+	union page_table_entry *table_entry = virtual_entry(dir, vaddr);
+	if (!table_entry)
+		return 0;
 	return (table_entry->bits.address * PAGE_SIZE) + (vaddr & (PAGE_SIZE - 1));
 }
 
@@ -457,7 +468,7 @@ void memory_map_identity(struct page_dir *dir, struct memory_range prange, u32 f
 static struct list *memory_objects = NULL;
 res memory_sys_alloc(struct page_dir *dir, u32 size, u32 *addr, u32 *id, u8 shared)
 {
-	if (!memory_valid(addr) || !memory_valid(id))
+	if (!memory_writable(addr) || !memory_writable(id))
 		return -EFAULT;
 
 	size = PAGE_ALIGN_UP(size);
@@ -488,7 +499,7 @@ res memory_sys_alloc(struct page_dir *dir, u32 size, u32 *addr, u32 *id, u8 shar
 
 res memory_sys_free(struct page_dir *dir, u32 addr)
 {
-	if (!addr || !memory_valid((void *)addr))
+	if (!addr || !memory_readable((void *)addr))
 		return -EFAULT;
 
 	struct list *links = proc_current()->memory;
@@ -516,7 +527,7 @@ res memory_sys_free(struct page_dir *dir, u32 addr)
 
 res memory_sys_shaccess(struct page_dir *dir, u32 id, u32 *addr, u32 *size)
 {
-	if (!memory_valid(addr) || !memory_valid(size))
+	if (!memory_writable(addr) || !memory_writable(size))
 		return -EFAULT;
 
 	struct node *iterator = memory_objects->head;
@@ -576,16 +587,25 @@ void memory_bypass_disable(void)
 	memory_bypass_validity = 0;
 }
 
-u8 memory_is_user(u32 addr)
+u8 memory_is_user(const void *addr)
 {
-	return PDI(addr) >= PAGE_KERNEL_COUNT;
+	return PDI((u32)addr) >= PAGE_KERNEL_COUNT;
 }
 
-// TODO: Limit by proc stack and data range
-u8 memory_valid(const void *addr)
+u8 memory_readable(const void *addr)
 {
-	if (proc_current() && !memory_bypass_validity)
-		return memory_is_user((u32)addr);
+	struct proc *proc = proc_current();
+	if (proc && !memory_bypass_validity)
+		return memory_is_user(addr) && virtual_user_readable(proc->page_dir, (u32)addr);
+	else
+		return 1;
+}
+
+u8 memory_writable(const void *addr)
+{
+	struct proc *proc = proc_current();
+	if (proc && !memory_bypass_validity)
+		return memory_is_user(addr) && virtual_user_writable(proc->page_dir, (u32)addr);
 	else
 		return 1;
 }