On 1/15/24 20:37, Matthew Wilcox wrote:
On Mon, Jan 15, 2024 at 08:22:19PM +0100, Bernd Edlinger wrote:
This introduces signal->exec_bprm, which is used to fix the case when at least one of the sibling threads is traced, and therefore the trace process may dead-lock in ptrace_attach, but de_thread will need to wait for the tracer to continue execution.
Not entirely sure why I've been added to the cc; this doesn't seem like it's even remotely within my realm of expertise.
Ah, okay, never mind. A couple new email addresses were found this time when I used ./scripts/get_maintainer.pl
+++ b/include/linux/cred.h @@ -153,6 +153,7 @@ extern const struct cred *get_task_cred(struct task_struct *); extern struct cred *cred_alloc_blank(void); extern struct cred *prepare_creds(void); extern struct cred *prepare_exec_creds(void); +extern bool is_dumpability_changed(const struct cred *, const struct cred *);
Using 'extern' for function declarations is deprecated. More importantly, you have two arguments of the same type, and how do I know which one is which if you don't name them?
+++ b/kernel/cred.c @@ -375,6 +375,28 @@ static bool cred_cap_issubset(const struct cred *set, const struct cred *subset) return false; } +/**
- is_dumpability_changed - Will changing creds from old to new
- affect the dumpability in commit_creds?
- Return: false - dumpability will not be changed in commit_creds.
true - dumpability will be changed to non-dumpable.
- @old: The old credentials
- @new: The new credentials
- */
Does kernel-doc really parse this correctly? Normal style would be:
Apparently yes, but I think I only added those lines to silence some automatic checking bots.
/**
- is_dumpability_changed - Will changing creds affect dumpability?
- @old: The old credentials.
- @new: The new credentials.
- If the @new credentials have no elevated privileges compared to the
- @old credentials, the task may remain dumpable. Otherwise we have
- to mark the task as undumpable to avoid information leaks from higher
- to lower privilege domains.
- Return: True if the task will become undumpable.
*/
Thanks a lot, that looks much better. I will use your suggestion as is, when I re-send the patch next time.
@@ -508,6 +531,14 @@ static int ptrace_traceme(void) { int ret = -EPERM;
- if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex))
return -ERESTARTNOINTR;Do you really want this to be interruptible by a timer signal or a window resize event?
I think that is kind of okay, as most of the existing users lock the mutex also interruptible, so I just wanted to follow those examples.
Thanks Bernd.