-
Notifications
You must be signed in to change notification settings - Fork 2.1k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
1 parent
d433185
commit e3aef00
Showing
2 changed files
with
50 additions
and
1 deletion.
There are no files selected for viewing
49 changes: 49 additions & 0 deletions
49
srcpkgs/musl/patches/avoid-set-id-setrlimit-misbehavior-and-hang-in-vfork.patch
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,49 @@ | ||
From a5aff1972c9e3981566414b09a28e331ccd2be5d Mon Sep 17 00:00:00 2001 | ||
From: Rich Felker <dalias@aerifal.cx> | ||
Date: Thu, 17 Sep 2020 15:09:46 -0400 | ||
Subject: [PATCH 237/513] avoid set*id/setrlimit misbehavior and hang in | ||
vforked/cloned child | ||
|
||
taking the deprecated/dropped vfork spec strictly, doing pretty much | ||
anything but execve in the child is wrong and undefined. however, | ||
these are commonly needed operations to setup the child state before | ||
exec, and historical implementations tolerated them. | ||
|
||
for single-threaded parents, these operations already worked as | ||
expected in the vforked child. however, due to the need for __synccall | ||
to synchronize id/resource limit changes among all threads, calling | ||
these functions in the vforked child of a multithreaded parent caused | ||
a misdirected broadcast signaling of all threads in the parent. these | ||
signals could kill the parent entirely if the synccall signal handler | ||
had never been installed in the parent, or could be ignored if it had, | ||
or could signal/kill one or more utterly wrong processes if the parent | ||
already terminated (due to vfork semantics, only possible via fatal | ||
signal) and the parent tids were recycled. in any case, the expected | ||
number of semaphore posts would never happen, so the child would | ||
permanently hang (with all signals blocked) waiting for them. | ||
|
||
to mitigate this, and also make the normal usage case work as | ||
intended, treat the condition where the caller's actual tid does not | ||
match the tid in its thread structure as single-threaded, and bypass | ||
the entire synccall broadcast operation. | ||
--- | ||
src/thread/synccall.c | 3 ++- | ||
1 file changed, 2 insertions(+), 1 deletion(-) | ||
|
||
diff --git a/src/thread/synccall.c b/src/thread/synccall.c | ||
index 648a6ad4..d58c851f 100644 | ||
--- a/src/thread/synccall.c | ||
+++ b/src/thread/synccall.c | ||
@@ -63,7 +63,8 @@ void __synccall(void (*func)(void *), void *ctx) | ||
sem_init(&target_sem, 0, 0); | ||
sem_init(&caller_sem, 0, 0); | ||
|
||
- if (!libc.threads_minus_1) goto single_threaded; | ||
+ if (!libc.threads_minus_1 || __syscall(SYS_gettid) != self->tid) | ||
+ goto single_threaded; | ||
|
||
callback = func; | ||
context = ctx; | ||
-- | ||
2.41.0 | ||
|
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters