Messages in this thread Patch in this message | | | Date | Fri, 4 Jan 2008 12:15:02 +0100 | From | Guillaume Chazarain <> | Subject | Re: [PATCH] proc: advertise new restrictions on /proc/*/maps & /proc/*/smaps |
| |
Al Viro <viro@ZenIV.linux.org.uk> 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 <guichaz@yahoo.fr> ---
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
| |