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Commit ab8d11be authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Linus Torvalds
Browse files

[PATCH] remove duplicated code from proc and ptrace 



Extract common code used by ptrace_attach() and may_ptrace_attach()
into a separate function.

Signed-off-by: default avatarMiklos Szeredi <miklos@szeredi.hu>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 5e21ccb1

fs/proc/base.c

+4 −31
Original line number Diff line number Diff line
@@ -346,33 +346,6 @@ static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vf 
	 (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \

	 security_ptrace(current,task) == 0))



static int may_ptrace_attach(struct task_struct *task)

{

	int retval = 0;



	task_lock(task);



	if (!task->mm)

		goto out;

	if (((current->uid != task->euid) ||

	     (current->uid != task->suid) ||

	     (current->uid != task->uid) ||

	     (current->gid != task->egid) ||

	     (current->gid != task->sgid) ||

	     (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))

		goto out;

	rmb();

	if (task->mm->dumpable != 1 && !capable(CAP_SYS_PTRACE))

		goto out;

	if (security_ptrace(current, task))

		goto out;



	retval = 1;

out:

	task_unlock(task);

	return retval;

}



static int proc_pid_environ(struct task_struct *task, char * buffer)

{

	int res = 0;
@@ -382,7 +355,7 @@ static int proc_pid_environ(struct task_struct *task, char * buffer) 
		if (len > PAGE_SIZE)

			len = PAGE_SIZE;

		res = access_process_vm(task, mm->env_start, buffer, len, 0);

		if (!may_ptrace_attach(task))

		if (!ptrace_may_attach(task))

			res = -ESRCH;

		mmput(mm);

	}
@@ -685,7 +658,7 @@ static ssize_t mem_read(struct file * file, char __user * buf, 
	int ret = -ESRCH;

	struct mm_struct *mm;



	if (!MAY_PTRACE(task) || !may_ptrace_attach(task))

	if (!MAY_PTRACE(task) || !ptrace_may_attach(task))

		goto out;



	ret = -ENOMEM;
@@ -711,7 +684,7 @@ static ssize_t mem_read(struct file * file, char __user * buf, 


		this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;

		retval = access_process_vm(task, src, page, this_len, 0);

		if (!retval || !MAY_PTRACE(task) || !may_ptrace_attach(task)) {

		if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) {

			if (!ret)

				ret = -EIO;

			break;
@@ -749,7 +722,7 @@ static ssize_t mem_write(struct file * file, const char * buf, 
	struct task_struct *task = proc_task(file->f_dentry->d_inode);

	unsigned long dst = *ppos;



	if (!MAY_PTRACE(task) || !may_ptrace_attach(task))

	if (!MAY_PTRACE(task) || !ptrace_may_attach(task))

		return -ESRCH;



	page = (char *)__get_free_page(GFP_USER);

include/linux/ptrace.h

+1 −0
Original line number Diff line number Diff line
@@ -90,6 +90,7 @@ extern void __ptrace_link(struct task_struct *child, 
			  struct task_struct *new_parent);

extern void __ptrace_unlink(struct task_struct *child);

extern void ptrace_untrace(struct task_struct *child);

extern int ptrace_may_attach(struct task_struct *task);



static inline void ptrace_link(struct task_struct *child,

			       struct task_struct *new_parent)

kernel/ptrace.c

+28 −13
Original line number Diff line number Diff line
@@ -118,31 +118,46 @@ int ptrace_check_attach(struct task_struct *child, int kill) 
	return ret;

}



int ptrace_attach(struct task_struct *task)

static int may_attach(struct task_struct *task)

{

	int retval;

	task_lock(task);

	retval = -EPERM;

	if (task->pid <= 1)

		goto bad;

	if (task == current)

		goto bad;

	if (!task->mm)

		goto bad;

		return -EPERM;

	if (((current->uid != task->euid) ||

	     (current->uid != task->suid) ||

	     (current->uid != task->uid) ||

	     (current->gid != task->egid) ||

	     (current->gid != task->sgid) ||

	     (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))

		goto bad;

		return -EPERM;

	smp_rmb();

	if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))

		return -EPERM;



	return security_ptrace(current, task);

}



int ptrace_may_attach(struct task_struct *task)

{

	int err;

	task_lock(task);

	err = may_attach(task);

	task_unlock(task);

	return !err;

}



int ptrace_attach(struct task_struct *task)

{

	int retval;

	task_lock(task);

	retval = -EPERM;

	if (task->pid <= 1)

		goto bad;

	if (task == current)

		goto bad;

	/* the same process cannot be attached many times */

	if (task->ptrace & PT_PTRACED)

		goto bad;

	retval = security_ptrace(current, task);

	retval = may_attach(task);

	if (retval)

		goto bad;