Added range-based memory validator

4 files changed, 36 insertions, 28 deletions

diff --git a/kernel/features/fs.c b/kernel/features/fs.c
index 34c70e8..6cb10c8 100644
--- a/kernel/features/fs.c
+++ b/kernel/features/fs.c
@@ -147,7 +147,7 @@ res vfs_read(const char *path, void *buf, u32 offset, u32 count)
 	if (!memory_readable(path))
 		return -EFAULT;
 
-	if (!memory_writable(buf))
+	if (!memory_writable_range(memory_range(buf, count)))
 		return -EFAULT;
 
 	struct mount_info *m = vfs_find_mount_info(path);
@@ -170,12 +170,12 @@ res vfs_read(const char *path, void *buf, u32 offset, u32 count)
 	return m->dev->vfs->read(path, buf, offset, count, m->dev);
 }
 
-res vfs_write(const char *path, void *buf, u32 offset, u32 count)
+res vfs_write(const char *path, const void *buf, u32 offset, u32 count)
 {
 	if (!memory_readable(path))
 		return -EFAULT;
 
-	if (!memory_writable(buf))
+	if (!memory_readable_range(memory_range(buf, count)))
 		return -EFAULT;
 
 	struct mount_info *m = vfs_find_mount_info(path);
@@ -203,7 +203,7 @@ res vfs_stat(const char *path, struct stat *buf)
 	if (!memory_readable(path))
 		return -EFAULT;
 
-	if (!memory_writable(buf))
+	if (!memory_writable_range(memory_range(buf, sizeof(*buf))))
 		return -EFAULT;
 
 	struct mount_info *m = vfs_find_mount_info(path);
diff --git a/kernel/features/io.c b/kernel/features/io.c
index fbae5cf..d4737bf 100644
--- a/kernel/features/io.c
+++ b/kernel/features/io.c
@@ -120,7 +120,7 @@ res io_control(enum io_type io, u32 request, void *arg1, void *arg2, void *arg3)
 
 res io_write(enum io_type io, const void *buf, u32 offset, u32 count)
 {
-	if (!memory_readable(buf))
+	if (!memory_readable_range(memory_range(buf, count)))
 		return -EFAULT;
 
 	struct io_dev *dev;
@@ -132,7 +132,7 @@ res io_write(enum io_type io, const void *buf, u32 offset, u32 count)
 
 res io_read(enum io_type io, void *buf, u32 offset, u32 count)
 {
-	if (!memory_readable(buf))
+	if (!memory_writable_range(memory_range(buf, count)))
 		return -EFAULT;
 
 	struct io_dev *dev;
diff --git a/kernel/features/mm.c b/kernel/features/mm.c
index 4ed3ab9..a3812bd 100644
--- a/kernel/features/mm.c
+++ b/kernel/features/mm.c
@@ -608,28 +608,48 @@ u8 memory_is_user(const void *addr)
 	return PDI((u32)addr) >= PAGE_KERNEL_COUNT;
 }
 
-u8 memory_readable(const void *addr)
+u8 memory_readable_range(struct memory_range vrange)
 {
-	if (!addr)
+	if (!vrange.base)
 		return 0;
 
 	struct proc *proc = proc_current();
-	if (proc && !memory_bypass_validity)
-		return memory_is_user(addr) && virtual_user_readable(proc->page_dir, (u32)addr);
-	else
+	if (memory_bypass_validity || !proc)
 		return 1;
+
+	u32 offset = 0;
+	do {
+		u8 valid = memory_is_user((void *)(vrange.base + offset)) &&
+			   virtual_user_readable(proc->page_dir, vrange.base + offset);
+		if (!valid)
+			return 0;
+
+		offset += PAGE_SIZE;
+	} while (offset < vrange.size);
+
+	return 1;
 }
 
-u8 memory_writable(const void *addr)
+u8 memory_writable_range(struct memory_range vrange)
 {
-	if (!addr)
+	if (!vrange.base)
 		return 0;
 
 	struct proc *proc = proc_current();
-	if (proc && !memory_bypass_validity)
-		return memory_is_user(addr) && virtual_user_writable(proc->page_dir, (u32)addr);
-	else
+	if (memory_bypass_validity || !proc)
 		return 1;
+
+	u32 offset = 0;
+	do {
+		u8 valid = memory_is_user((void *)(vrange.base + offset)) &&
+			   virtual_user_writable(proc->page_dir, vrange.base + offset);
+		if (!valid)
+			return 0;
+
+		offset += PAGE_SIZE;
+	} while (offset < vrange.size);
+
+	return 1;
 }
 
 struct memory_range memory_range_from(u32 base, u32 size)
diff --git a/kernel/features/proc.c b/kernel/features/proc.c
index 4cf4005..b47df0b 100644
--- a/kernel/features/proc.c
+++ b/kernel/features/proc.c
@@ -256,17 +256,6 @@ struct procfs_message {
 	u32 size;
 };
 
-static res procfs_write(const char *path, void *buf, u32 offset, u32 count, struct vfs_dev *dev)
-{
-	UNUSED(path);
-	UNUSED(buf);
-	UNUSED(offset);
-	UNUSED(count);
-	UNUSED(dev);
-
-	return -ENOENT;
-}
-
 static res procfs_read(const char *path, void *buf, u32 offset, u32 count, struct vfs_dev *dev)
 {
 	(void)dev;
@@ -331,7 +320,6 @@ NORETURN void proc_init(void)
 	struct vfs *vfs = zalloc(sizeof(*vfs));
 	vfs->type = VFS_PROCFS;
 	vfs->read = procfs_read;
-	vfs->write = procfs_write;
 	vfs->perm = procfs_perm;
 	vfs->data = NULL;
 	struct vfs_dev *dev = zalloc(sizeof(*dev));