/proc/*/mem and /proc/*/environ use common code to check if open is
allowed. Essentially they all access target task memory.
/proc/*/cmdline should be subject to the same checks as it does
what /proc/*/environ does.
->security_ptrace_access_check LSM hook will be called allowing LSM
to interfere.
Signed-off-by: Alexey Dobriyan <adobri...@gmail.com>
---
fs/proc/base.c | 67 ++++++++++++++++++++++++++++-----------------------------
1 file changed, 33 insertions(+), 34 deletions(-)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -208,11 +208,34 @@ static int proc_root_link(struct dentry *dentry, struct
path *path)
return result;
}
+static int __mem_open(struct inode *inode, struct file *file, unsigned int
mode)
+{
+ struct mm_struct *mm = proc_mem_open(inode, mode);
+
+ if (IS_ERR(mm))
+ return PTR_ERR(mm);
+
+ file->private_data = mm;
+ return 0;
+}
+
+static int proc_pid_cmdline_open(struct inode *inode, struct file *file)
+{
+ return __mem_open(inode, file, PTRACE_MODE_READ);
+}
+
+static int mem_release(struct inode *inode, struct file *file)
+{
+ struct mm_struct *mm = file->private_data;
+ if (mm)
+ mmdrop(mm);
+ return 0;
+}
+
static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
size_t _count, loff_t *pos)
{
- struct task_struct *tsk;
- struct mm_struct *mm;
+ struct mm_struct *mm = file->private_data;
char *page;
unsigned long count = _count;
unsigned long arg_start, arg_end, env_start, env_end;
@@ -223,18 +246,11 @@ static ssize_t proc_pid_cmdline_read(struct file *file,
char __user *buf,
BUG_ON(*pos < 0);
- tsk = get_proc_task(file_inode(file));
- if (!tsk)
- return -ESRCH;
- mm = get_task_mm(tsk);
- put_task_struct(tsk);
- if (!mm)
- return 0;
/* Check if process spawned far enough to have cmdline. */
- if (!mm->env_end) {
- rv = 0;
- goto out_mmput;
- }
+ if (!mm || !mm->env_end)
+ return 0;
+ if (!mmget_not_zero(mm))
+ return 0;
page = (char *)__get_free_page(GFP_KERNEL);
if (!page) {
@@ -376,8 +392,10 @@ static ssize_t proc_pid_cmdline_read(struct file *file,
char __user *buf,
}
static const struct file_operations proc_pid_cmdline_ops = {
- .read = proc_pid_cmdline_read,
- .llseek = generic_file_llseek,
+ .open = proc_pid_cmdline_open,
+ .read = proc_pid_cmdline_read,
+ .llseek = generic_file_llseek,
+ .release = mem_release,
};
#ifdef CONFIG_KALLSYMS
@@ -786,17 +804,6 @@ struct mm_struct *proc_mem_open(struct inode *inode,
unsigned int mode)
return mm;
}
-static int __mem_open(struct inode *inode, struct file *file, unsigned int
mode)
-{
- struct mm_struct *mm = proc_mem_open(inode, mode);
-
- if (IS_ERR(mm))
- return PTR_ERR(mm);
-
- file->private_data = mm;
- return 0;
-}
-
static int mem_open(struct inode *inode, struct file *file)
{
int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
@@ -890,14 +897,6 @@ 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;
- if (mm)
- mmdrop(mm);
- return 0;
-}
-
static const struct file_operations proc_mem_operations = {
.llseek = mem_lseek,
.read = mem_read,
