restrict reading from /proc/<pid>/maps to those who share ->mm or can ptrace pid
Contents of /proc/*/maps is sensitive and may become sensitive after
open() (e.g. if target originally shares our ->mm and later does exec
on suid-root binary).
Check at read() (actually, ->start() of iterator) time that mm_struct
we'd grabbed and locked is
- still the ->mm of target
- equal to reader's ->mm or the target is ptracable by reader.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 7c76f2f..0c65d30 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -120,7 +120,7 @@
return ret;
}
-static int may_attach(struct task_struct *task)
+int __ptrace_may_attach(struct task_struct *task)
{
/* May we inspect the given task?
* This check is used both for attaching with ptrace
@@ -154,7 +154,7 @@
{
int err;
task_lock(task);
- err = may_attach(task);
+ err = __ptrace_may_attach(task);
task_unlock(task);
return !err;
}