commit 5096add84b9e96e2e0a9c72675c442fe5433388a
"proc: maps protection"
commit 831830b5a2b5d413407adf380ef62fe17d6fcbf2
"restrict reading from /proc/<pid>/maps to those who share ->mm or can ptrace pid"
After Al added mm_for_maps(), maps_protect stopped controlling anything,
because they're run at ->show time, but mm_for_maps() checks are done at
->start time.
Unless anyone objects, I'll remove maps_protect.
Also, logic behind second commit applies to /proc/*/pagemap , don't you
think?
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 7f268f3..040d5c4 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1288,13 +1288,6 @@ determine whether or not they are still functioning properly.
Because the NMI watchdog shares registers with oprofile, by disabling the NMI
watchdog, oprofile may have more registers to utilize.
-maps_protect
-------------
-
-Enables/Disables the protection of the per-process proc entries "maps" and
-"smaps". When enabled, the contents of these files are visible only to
-readers that are allowed to ptrace() the given process.
-
2.4 /proc/sys/vm - The virtual memory subsystem
-----------------------------------------------
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 58c3e6a..b0599d5 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -146,9 +146,6 @@ static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
return count;
}
-int maps_protect;
-EXPORT_SYMBOL(maps_protect);
-
static struct fs_struct *get_fs_struct(struct task_struct *task)
{
struct fs_struct *fs;
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 28cbca8..26ffe7d 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -45,8 +45,6 @@ do { \
extern int nommu_vma_show(struct seq_file *, struct vm_area_struct *);
#endif
-extern int maps_protect;
-
extern int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task);
extern int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 164bd9f..13c5d35 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -210,9 +210,6 @@ static int show_map(struct seq_file *m, void *v)
dev_t dev = 0;
int len;
- if (maps_protect && !ptrace_may_access(task, PTRACE_MODE_READ))
- return -EACCES;
-
if (file) {
struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
dev = inode->i_sb->s_dev;
@@ -742,22 +739,11 @@ const struct file_operations proc_pagemap_operations = {
#ifdef CONFIG_NUMA
extern int show_numa_map(struct seq_file *m, void *v);
-static int show_numa_map_checked(struct seq_file *m, void *v)
-{
- struct proc_maps_private *priv = m->private;
- struct task_struct *task = priv->task;
-
- if (maps_protect && !ptrace_may_access(task, PTRACE_MODE_READ))
- return -EACCES;
-
- return show_numa_map(m, v);
-}
-
static const struct seq_operations proc_pid_numa_maps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
- .show = show_numa_map_checked
+ .show = show_numa_map,
};
static int numa_maps_open(struct inode *inode, struct file *file)
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 5d84e71..3af080a 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -113,9 +113,6 @@ static int show_map(struct seq_file *m, void *_vml)
struct proc_maps_private *priv = m->private;
struct task_struct *task = priv->task;
- if (maps_protect && !ptrace_may_access(task, PTRACE_MODE_READ))
- return -EACCES;
-
return nommu_vma_show(m, vml->vma);
}
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 6b16e16..fb76984 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -79,7 +79,6 @@ extern int pid_max_min, pid_max_max;
extern int sysctl_drop_caches;
extern int percpu_pagelist_fraction;
extern int compat_log;
-extern int maps_protect;
extern int sysctl_stat_interval;
extern int latencytop_enabled;
extern int sysctl_nr_open_min, sysctl_nr_open_max;
@@ -796,16 +795,6 @@ static struct ctl_table kern_table[] = {
.proc_handler = &proc_dointvec,
},
#endif
-#ifdef CONFIG_PROC_FS
- {
- .ctl_name = CTL_UNNUMBERED,
- .procname = "maps_protect",
- .data = &maps_protect,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &proc_dointvec,
- },
-#endif
{
.ctl_name = CTL_UNNUMBERED,
.procname = "poweroff_cmd",
Hi,
On Wed, Jul 16, 2008 at 06:11:35AM +0400, Alexey Dobriyan wrote:
> commit 5096add84b9e96e2e0a9c72675c442fe5433388a
> "proc: maps protection"
>
> commit 831830b5a2b5d413407adf380ef62fe17d6fcbf2
> "restrict reading from /proc/<pid>/maps to those who share ->mm or can ptrace pid"
>
> After Al added mm_for_maps(), maps_protect stopped controlling anything,
> because they're run at ->show time, but mm_for_maps() checks are done at
> ->start time.
>
> Unless anyone objects, I'll remove maps_protect.
As long as this provides the same protections as maps_protect, I'm fine
with it. I am a bit confused, though, since the reason I had to create
the sysctl entry in the first place was because akpm objected to the
maps file disappearing without a tunable. Has this objection gone away?
> Also, logic behind second commit applies to /proc/*/pagemap , don't you
> think?
If that file shows memory location, yes. What about the numa maps that
the first commit protects?
Thanks,
-Kees
--
Kees Cook @outflux.net