Al Viro <[EMAIL PROTECTED]> wrote:
> The whole point is that we have to reject it at read() time, not open()
> time.
Yes, my patch was a complement to yours to propagate the -EPERM in easy
cases. As you noted it added restrictions on reading /proc/*/maps, even
though I found them acceptable.
How about this instead?
Maybe you'd prefer to propagate the actual -EPERM from
__ptrace_may_attach but that would be more invasive.
Sidenote: do you think a sparse annotation to check IS_ERR/PTR_ERR
usage would make sense?
proc: return -EPERM when preventing read of /proc/*/maps
Return an error instead of successfully reading an empty file.
Signed-off-by: Guillaume Chazarain <[EMAIL PROTECTED]>
---
fs/proc/base.c | 2 +-
fs/proc/task_mmu.c | 8 +++++---
fs/proc/task_nommu.c | 4 ++--
3 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 7411bfb..3aebc85 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -219,7 +219,7 @@ out:
task_unlock(task);
up_read(&mm->mmap_sem);
mmput(mm);
- return NULL;
+ return ERR_PTR(-EPERM);
}
static int proc_pid_cmdline(struct task_struct *task, char * buffer)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 8043a3e..db57e65 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -398,8 +398,8 @@ static void *m_start(struct seq_file *m, loff_t
*pos) return NULL;
mm = mm_for_maps(priv->task);
- if (!mm)
- return NULL;
+ if (IS_ERR(mm) || !mm)
+ return mm;
priv->tail_vma = tail_vma = get_gate_vma(priv->task);
@@ -437,7 +437,7 @@ out:
static void vma_stop(struct proc_maps_private *priv, struct
vm_area_struct *vma) {
- if (vma && vma != priv->tail_vma) {
+ if (vma && !IS_ERR(vma) && vma != priv->tail_vma) {
struct mm_struct *mm = vma->vm_mm;
up_read(&mm->mmap_sem);
mmput(mm);
@@ -451,6 +451,8 @@ static void *m_next(struct seq_file *m, void *v,
loff_t *pos) struct vm_area_struct *tail_vma = priv->tail_vma;
(*pos)++;
+ if (IS_ERR(vma))
+ return vma;
if (vma && (vma != tail_vma) && vma->vm_next)
return vma->vm_next;
vma_stop(priv, vma);
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 1932c2c..53cb062 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -166,10 +166,10 @@ static void *m_start(struct seq_file *m, loff_t
*pos) return NULL;
mm = mm_for_maps(priv->task);
- if (!mm) {
+ if (IS_ERR(mm) || !mm) {
put_task_struct(priv->task);
priv->task = NULL;
- return NULL;
+ return mm;
}
/* start from the Nth VMA */
--
Guillaume
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