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-rw-r--r--proc-clean-up-and-fix-proc-pid-mem-handling.patch268
1 files changed, 0 insertions, 268 deletions
diff --git a/proc-clean-up-and-fix-proc-pid-mem-handling.patch b/proc-clean-up-and-fix-proc-pid-mem-handling.patch
deleted file mode 100644
index c793475d2..000000000
--- a/proc-clean-up-and-fix-proc-pid-mem-handling.patch
+++ /dev/null
@@ -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=UTF-8
-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,
---
-1.7.7.5
-
generated by cgit (git 2.34.1) at 2024-06-08 17:45:11 +0000