Added filesystem and proc permissions

5 files changed, 76 insertions, 8 deletions

diff --git a/kernel/drivers/ide.c b/kernel/drivers/ide.c
index 7dd2416..8fc90c9 100644
--- a/kernel/drivers/ide.c
+++ b/kernel/drivers/ide.c
@@ -147,8 +147,9 @@ void ata_probe(void)
 		struct vfs *vfs = malloc(sizeof(*vfs));
 		vfs->type = VFS_EXT2;
 		vfs->read = ext2_read;
-		vfs->ready = ext2_ready;
 		vfs->stat = ext2_stat;
+		vfs->perm = ext2_perm;
+		vfs->ready = ext2_ready;
 		dev->vfs = vfs;
 		dev->data = data;
 		vfs_mount(dev, "/");
diff --git a/kernel/features/fs.c b/kernel/features/fs.c
index b59eb03..ecb2b85 100644
--- a/kernel/features/fs.c
+++ b/kernel/features/fs.c
@@ -130,12 +130,15 @@ s32 vfs_read(const char *path, void *buf, u32 offset, u32 count)
 		path++;
 
 	struct mount_info *m = vfs_find_mount_info(path);
-	assert(m && m->dev && m->dev->vfs && m->dev->vfs->read);
+	assert(m && m->dev && m->dev->vfs && m->dev->vfs->read && m->dev->vfs->perm);
 
 	u32 len = strlen(m->path);
 	if (len > 1)
 		path += len;
 
+	if (!m->dev->vfs->perm(path, VFS_READ, m->dev) && !proc_super())
+		return -1;
+
 	return m->dev->vfs->read(path, buf, offset, count, m->dev);
 }
 
@@ -151,12 +154,15 @@ s32 vfs_write(const char *path, void *buf, u32 offset, u32 count)
 		path++;
 
 	struct mount_info *m = vfs_find_mount_info(path);
-	assert(m && m->dev && m->dev->vfs && m->dev->vfs->write);
+	assert(m && m->dev && m->dev->vfs && m->dev->vfs->write && m->dev->vfs->perm);
 
 	u32 len = strlen(m->path);
 	if (len > 1)
 		path += len;
 
+	if (!m->dev->vfs->perm(path, VFS_WRITE, m->dev) && !proc_super())
+		return -1;
+
 	return m->dev->vfs->write(path, buf, offset, count, m->dev);
 }
 
@@ -237,6 +243,14 @@ s32 devfs_read(const char *path, void *buf, u32 offset, u32 count, struct device
 	return target->read(buf, offset, count, dev);
 }
 
+u8 devfs_perm(const char *path, enum vfs_perm perm, struct device *dev)
+{
+	(void)path;
+	(void)perm;
+	(void)dev;
+	return 1;
+}
+
 u8 devfs_ready(const char *path, struct device *dev)
 {
 	(void)dev;
@@ -307,7 +321,7 @@ struct ext2_inode *get_inode(u32 i, struct device *dev)
 		(struct ext2_inode *)((u32)buf +
 				      (index % (BLOCK_SIZE / EXT2_INODE_SIZE)) * EXT2_INODE_SIZE);
 
-	free(buf);
+	free(buf); // TODO: Fix use after free with *in
 	free(s);
 	free(b - block_group);
 
@@ -466,6 +480,22 @@ s32 ext2_stat(const char *path, struct stat *buf, struct device *dev)
 	return 0;
 }
 
+u8 ext2_perm(const char *path, enum vfs_perm perm, struct device *dev)
+{
+	struct ext2_inode *in = find_inode_by_path(path, dev);
+
+	switch (perm) {
+	case VFS_EXEC:
+		return (in->mode & EXT2_PERM_UEXEC) != 0;
+	case VFS_WRITE:
+		return (in->mode & EXT2_PERM_UWRITE) != 0;
+	case VFS_READ:
+		return (in->mode & EXT2_PERM_UREAD) != 0;
+	default:
+		return 0;
+	}
+}
+
 u8 ext2_ready(const char *path, struct device *dev)
 {
 	(void)path;
diff --git a/kernel/features/proc.c b/kernel/features/proc.c
index bec48fa..5dde2bd 100644
--- a/kernel/features/proc.c
+++ b/kernel/features/proc.c
@@ -14,10 +14,10 @@
 
 u32 current_pid = 0;
 u32 quantum = 0;
-struct proc *priority_proc;
-struct list *proc_list;
-struct node *idle_proc;
-struct node *current;
+struct proc *priority_proc = NULL;
+struct list *proc_list = NULL;
+struct node *idle_proc = NULL;
+struct node *current = NULL;
 
 // TODO: Use less memcpy and only copy relevant registers
 // TODO: 20 priority queues (https://www.kernel.org/doc/html/latest/scheduler/sched-nice-design.html)
@@ -88,6 +88,17 @@ struct proc *proc_current(void)
 	return current && current->data ? current->data : NULL;
 }
 
+u8 proc_super(void)
+{
+	struct proc *proc = proc_current();
+	if (proc)
+		return proc->super;
+	else if (current_pid == 0)
+		return 1; // Kernel has super permissions
+	else
+		return 0; // Should never happen
+}
+
 struct proc *proc_from_pid(u32 pid)
 {
 	struct node *iterator = proc_list->head;
@@ -156,6 +167,7 @@ struct proc *proc_make(void)
 {
 	struct proc *proc = malloc(sizeof(*proc));
 	proc->pid = current_pid++;
+	proc->super = 0;
 	proc->messages = stack_new();
 	proc->state = PROC_RUNNING;
 
@@ -246,6 +258,14 @@ s32 procfs_read(const char *path, void *buf, u32 offset, u32 count, struct devic
 	return -1;
 }
 
+u8 procfs_perm(const char *path, enum vfs_perm perm, struct device *dev)
+{
+	(void)path;
+	(void)perm;
+	(void)dev;
+	return 1;
+}
+
 u8 procfs_ready(const char *path, struct device *dev)
 {
 	(void)path;
@@ -293,6 +313,7 @@ void proc_init(void)
 
 	_eip = ((struct proc *)new->data)->regs.eip;
 	_esp = ((struct proc *)new->data)->regs.useresp;
+	((struct proc *)new->data)->super = 1;
 
 	u32 argc = 2;
 	char **argv = malloc(sizeof(*argv) * (argc + 1));
diff --git a/kernel/inc/fs.h b/kernel/inc/fs.h
index 64f3970..1069597 100644
--- a/kernel/inc/fs.h
+++ b/kernel/inc/fs.h
@@ -32,6 +32,7 @@ void device_add(struct device *dev);
  */
 
 enum vfs_type { VFS_DEVFS, VFS_TMPFS, VFS_PROCFS, VFS_EXT2 };
+enum vfs_perm { VFS_EXEC, VFS_WRITE, VFS_READ };
 
 struct vfs {
 	enum vfs_type type;
@@ -40,6 +41,7 @@ struct vfs {
 	s32 (*read)(const char *path, void *buf, u32 offset, u32 count, struct device *dev);
 	s32 (*write)(const char *path, void *buf, u32 offset, u32 count, struct device *dev);
 	s32 (*stat)(const char *path, struct stat *buf, struct device *dev);
+	u8 (*perm)(const char *path, enum vfs_perm perm, struct device *dev);
 	u8 (*ready)(const char *path, struct device *dev);
 };
 
@@ -71,6 +73,17 @@ struct device *device_get_by_name(const char *name);
 #define EXT2_ROOT 2
 #define EXT2_MAGIC 0x0000EF53
 
+// TODO: Support other and group permissions?
+#define EXT2_PERM_OEXEC 0x001
+#define EXT2_PERM_OWRITE 0x002
+#define EXT2_PERM_OREAD 0x004
+#define EXT2_PERM_GEXEC 0x008
+#define EXT2_PERM_GWRITE 0x010
+#define EXT2_PERM_GREAD 0x020
+#define EXT2_PERM_UEXEC 0x040
+#define EXT2_PERM_UWRITE 0x080
+#define EXT2_PERM_UREAD 0x100
+
 struct ext2_superblock {
 	u32 total_inodes;
 	u32 total_blocks;
@@ -155,6 +168,7 @@ struct ext2_file {
 
 s32 ext2_read(const char *path, void *buf, u32 offset, u32 count, struct device *dev);
 s32 ext2_stat(const char *path, struct stat *buf, struct device *dev);
+u8 ext2_perm(const char *path, enum vfs_perm perm, struct device *dev);
 u8 ext2_ready(const char *path, struct device *dev);
 
 #endif
diff --git a/kernel/inc/proc.h b/kernel/inc/proc.h
index 6be7da3..4a75638 100644
--- a/kernel/inc/proc.h
+++ b/kernel/inc/proc.h
@@ -26,6 +26,7 @@ struct proc_wait {
 
 struct proc {
 	u32 pid;
+	u8 super;
 	char name[32];
 	struct regs regs;
 	struct proc_wait wait; // dev_id
@@ -37,6 +38,7 @@ void scheduler(struct regs *regs);
 void proc_init(void);
 void proc_print(void);
 struct proc *proc_current(void);
+u8 proc_super(void);
 struct proc *proc_from_pid(u32 pid);
 void proc_exit(struct proc *proc, int status);
 void proc_yield(struct regs *r);