proc: disable mem_write after exec
This change makes mem_write() observe the same constraints as mem_read(). This
is particularly important for mem_write as an accidental leak of the fd across
an exec could result in arbitrary modification of the target process' memory.
IOW, /proc/pid/mem is implicitly close-on-exec.
Signed-off-by: Stephen Wilson <wilsons@start.ca>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index e94b58b..9af49a3 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -850,6 +850,10 @@
if (check_mem_permission(task))
goto out;
+ copied = -EIO;
+ if (file->private_data != (void *)((long)current->self_exec_id))
+ goto out;
+
copied = -ENOMEM;
page = (char *)__get_free_page(GFP_TEMPORARY);
if (!page)