remove patch
This commit is contained in:
Tobias Powalowski
parent
29012873c1
commit
d0445d71e8
|
|
@ -1,268 +0,0 @@
|
|||
From e268337dfe26dfc7efd422a804dbb27977a3cccc Mon Sep 17 00:00:00 2001
|
||||
From: Linus Torvalds <torvalds@linux-foundation.org>
|
||||
Date: Tue, 17 Jan 2012 15:21:19 -0800
|
||||
Subject: [PATCH] proc: clean up and fix /proc/<pid>/mem handling
|
||||
MIME-Version: 1.0
|
||||
Content-Type: text/plain; charset=utf8
|
||||
Content-Transfer-Encoding: 8bit
|
||||
|
||||
Jüri Aedla reported that the /proc/<pid>/mem handling really isn't very
|
||||
robust, and it also doesn't match the permission checking of any of the
|
||||
other related files.
|
||||
|
||||
This changes it to do the permission checks at open time, and instead of
|
||||
tracking the process, it tracks the VM at the time of the open. That
|
||||
simplifies the code a lot, but does mean that if you hold the file
|
||||
descriptor open over an execve(), you'll continue to read from the _old_
|
||||
VM.
|
||||
|
||||
That is different from our previous behavior, but much simpler. If
|
||||
somebody actually finds a load where this matters, we'll need to revert
|
||||
this commit.
|
||||
|
||||
I suspect that nobody will ever notice - because the process mapping
|
||||
addresses will also have changed as part of the execve. So you cannot
|
||||
actually usefully access the fd across a VM change simply because all
|
||||
the offsets for IO would have changed too.
|
||||
|
||||
Reported-by: Jüri Aedla <asd@ut.ee>
|
||||
Cc: Al Viro <viro@zeniv.linux.org.uk>
|
||||
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||||
---
|
||||
fs/proc/base.c | 145 +++++++++++++++-----------------------------------------
|
||||
1 files changed, 39 insertions(+), 106 deletions(-)
|
||||
|
||||
diff --git a/fs/proc/base.c b/fs/proc/base.c
|
||||
index 5485a53..662ddf2 100644
|
||||
--- a/fs/proc/base.c
|
||||
+++ b/fs/proc/base.c
|
||||
@@ -198,65 +198,7 @@ static int proc_root_link(struct dentry *dentry, struct path *path)
|
||||
return result;
|
||||
}
|
||||
|
||||
-static struct mm_struct *__check_mem_permission(struct task_struct *task)
|
||||
-{
|
||||
- struct mm_struct *mm;
|
||||
-
|
||||
- mm = get_task_mm(task);
|
||||
- if (!mm)
|
||||
- return ERR_PTR(-EINVAL);
|
||||
-
|
||||
- /*
|
||||
- * A task can always look at itself, in case it chooses
|
||||
- * to use system calls instead of load instructions.
|
||||
- */
|
||||
- if (task == current)
|
||||
- return mm;
|
||||
-
|
||||
- /*
|
||||
- * If current is actively ptrace'ing, and would also be
|
||||
- * permitted to freshly attach with ptrace now, permit it.
|
||||
- */
|
||||
- if (task_is_stopped_or_traced(task)) {
|
||||
- int match;
|
||||
- rcu_read_lock();
|
||||
- match = (ptrace_parent(task) == current);
|
||||
- rcu_read_unlock();
|
||||
- if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH))
|
||||
- return mm;
|
||||
- }
|
||||
-
|
||||
- /*
|
||||
- * No one else is allowed.
|
||||
- */
|
||||
- mmput(mm);
|
||||
- return ERR_PTR(-EPERM);
|
||||
-}
|
||||
-
|
||||
-/*
|
||||
- * If current may access user memory in @task return a reference to the
|
||||
- * corresponding mm, otherwise ERR_PTR.
|
||||
- */
|
||||
-static struct mm_struct *check_mem_permission(struct task_struct *task)
|
||||
-{
|
||||
- struct mm_struct *mm;
|
||||
- int err;
|
||||
-
|
||||
- /*
|
||||
- * Avoid racing if task exec's as we might get a new mm but validate
|
||||
- * against old credentials.
|
||||
- */
|
||||
- err = mutex_lock_killable(&task->signal->cred_guard_mutex);
|
||||
- if (err)
|
||||
- return ERR_PTR(err);
|
||||
-
|
||||
- mm = __check_mem_permission(task);
|
||||
- mutex_unlock(&task->signal->cred_guard_mutex);
|
||||
-
|
||||
- return mm;
|
||||
-}
|
||||
-
|
||||
-struct mm_struct *mm_for_maps(struct task_struct *task)
|
||||
+static struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
|
||||
{
|
||||
struct mm_struct *mm;
|
||||
int err;
|
||||
@@ -267,7 +209,7 @@ struct mm_struct *mm_for_maps(struct task_struct *task)
|
||||
|
||||
mm = get_task_mm(task);
|
||||
if (mm && mm != current->mm &&
|
||||
- !ptrace_may_access(task, PTRACE_MODE_READ)) {
|
||||
+ !ptrace_may_access(task, mode)) {
|
||||
mmput(mm);
|
||||
mm = ERR_PTR(-EACCES);
|
||||
}
|
||||
@@ -276,6 +218,11 @@ struct mm_struct *mm_for_maps(struct task_struct *task)
|
||||
return mm;
|
||||
}
|
||||
|
||||
+struct mm_struct *mm_for_maps(struct task_struct *task)
|
||||
+{
|
||||
+ return mm_access(task, PTRACE_MODE_READ);
|
||||
+}
|
||||
+
|
||||
static int proc_pid_cmdline(struct task_struct *task, char * buffer)
|
||||
{
|
||||
int res = 0;
|
||||
@@ -752,38 +699,39 @@ static const struct file_operations proc_single_file_operations = {
|
||||
|
||||
static int mem_open(struct inode* inode, struct file* file)
|
||||
{
|
||||
- file->private_data = (void*)((long)current->self_exec_id);
|
||||
+ struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
|
||||
+ struct mm_struct *mm;
|
||||
+
|
||||
+ if (!task)
|
||||
+ return -ESRCH;
|
||||
+
|
||||
+ mm = mm_access(task, PTRACE_MODE_ATTACH);
|
||||
+ put_task_struct(task);
|
||||
+
|
||||
+ if (IS_ERR(mm))
|
||||
+ return PTR_ERR(mm);
|
||||
+
|
||||
/* OK to pass negative loff_t, we can catch out-of-range */
|
||||
file->f_mode |= FMODE_UNSIGNED_OFFSET;
|
||||
+ file->private_data = mm;
|
||||
+
|
||||
return 0;
|
||||
}
|
||||
|
||||
static ssize_t mem_read(struct file * file, char __user * buf,
|
||||
size_t count, loff_t *ppos)
|
||||
{
|
||||
- struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
|
||||
+ int ret;
|
||||
char *page;
|
||||
unsigned long src = *ppos;
|
||||
- int ret = -ESRCH;
|
||||
- struct mm_struct *mm;
|
||||
+ struct mm_struct *mm = file->private_data;
|
||||
|
||||
- if (!task)
|
||||
- goto out_no_task;
|
||||
+ if (!mm)
|
||||
+ return 0;
|
||||
|
||||
- ret = -ENOMEM;
|
||||
page = (char *)__get_free_page(GFP_TEMPORARY);
|
||||
if (!page)
|
||||
- goto out;
|
||||
-
|
||||
- mm = check_mem_permission(task);
|
||||
- ret = PTR_ERR(mm);
|
||||
- if (IS_ERR(mm))
|
||||
- goto out_free;
|
||||
-
|
||||
- ret = -EIO;
|
||||
-
|
||||
- if (file->private_data != (void*)((long)current->self_exec_id))
|
||||
- goto out_put;
|
||||
+ return -ENOMEM;
|
||||
|
||||
ret = 0;
|
||||
|
||||
@@ -810,13 +758,7 @@ static ssize_t mem_read(struct file * file, char __user * buf,
|
||||
}
|
||||
*ppos = src;
|
||||
|
||||
-out_put:
|
||||
- mmput(mm);
|
||||
-out_free:
|
||||
free_page((unsigned long) page);
|
||||
-out:
|
||||
- put_task_struct(task);
|
||||
-out_no_task:
|
||||
return ret;
|
||||
}
|
||||
|
||||
@@ -825,27 +767,15 @@ static ssize_t mem_write(struct file * file, const char __user *buf,
|
||||
{
|
||||
int copied;
|
||||
char *page;
|
||||
- struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
|
||||
unsigned long dst = *ppos;
|
||||
- struct mm_struct *mm;
|
||||
+ struct mm_struct *mm = file->private_data;
|
||||
|
||||
- copied = -ESRCH;
|
||||
- if (!task)
|
||||
- goto out_no_task;
|
||||
+ if (!mm)
|
||||
+ return 0;
|
||||
|
||||
- copied = -ENOMEM;
|
||||
page = (char *)__get_free_page(GFP_TEMPORARY);
|
||||
if (!page)
|
||||
- goto out_task;
|
||||
-
|
||||
- mm = check_mem_permission(task);
|
||||
- copied = PTR_ERR(mm);
|
||||
- if (IS_ERR(mm))
|
||||
- goto out_free;
|
||||
-
|
||||
- copied = -EIO;
|
||||
- if (file->private_data != (void *)((long)current->self_exec_id))
|
||||
- goto out_mm;
|
||||
+ return -ENOMEM;
|
||||
|
||||
copied = 0;
|
||||
while (count > 0) {
|
||||
@@ -869,13 +799,7 @@ static ssize_t mem_write(struct file * file, const char __user *buf,
|
||||
}
|
||||
*ppos = dst;
|
||||
|
||||
-out_mm:
|
||||
- mmput(mm);
|
||||
-out_free:
|
||||
free_page((unsigned long) page);
|
||||
-out_task:
|
||||
- put_task_struct(task);
|
||||
-out_no_task:
|
||||
return copied;
|
||||
}
|
||||
|
||||
@@ -895,11 +819,20 @@ loff_t mem_lseek(struct file *file, loff_t offset, int orig)
|
||||
return file->f_pos;
|
||||
}
|
||||
|
||||
+static int mem_release(struct inode *inode, struct file *file)
|
||||
+{
|
||||
+ struct mm_struct *mm = file->private_data;
|
||||
+
|
||||
+ mmput(mm);
|
||||
+ return 0;
|
||||
+}
|
||||
+
|
||||
static const struct file_operations proc_mem_operations = {
|
||||
.llseek = mem_lseek,
|
||||
.read = mem_read,
|
||||
.write = mem_write,
|
||||
.open = mem_open,
|
||||
+ .release = mem_release,
|
||||
};
|
||||
|
||||
static ssize_t environ_read(struct file *file, char __user *buf,
|
||||
--
|
||||
1.7.6.5
|
||||
|
||||
Loading…
Reference in New Issue