From 08b74a000942a380fe028845f92cd3a0dee827d5 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:02:38 +0200 Subject: Adding debian version 4.19.249-2. Signed-off-by: Daniel Baumann --- ...signal-Prevent-double-free-of-user-struct.patch | 55 ++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 debian/patches-rt/0329-signal-Prevent-double-free-of-user-struct.patch (limited to 'debian/patches-rt/0329-signal-Prevent-double-free-of-user-struct.patch') diff --git a/debian/patches-rt/0329-signal-Prevent-double-free-of-user-struct.patch b/debian/patches-rt/0329-signal-Prevent-double-free-of-user-struct.patch new file mode 100644 index 000000000..253dc5c91 --- /dev/null +++ b/debian/patches-rt/0329-signal-Prevent-double-free-of-user-struct.patch @@ -0,0 +1,55 @@ +From a99e09659e6cd4b633c3689f2c3aa5f8a816fe5b Mon Sep 17 00:00:00 2001 +From: Matt Fleming +Date: Tue, 7 Apr 2020 10:54:13 +0100 +Subject: [PATCH 329/347] signal: Prevent double-free of user struct +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +[ Upsteam commit 9567db2ebe566a93485e1a27d8759969d0002d7a ] + +The way user struct reference counting works changed significantly with, + + fda31c50292a ("signal: avoid double atomic counter increments for user accounting") + +Now user structs are only freed once the last pending signal is +dequeued. Make sigqueue_free_current() follow this new convention to +avoid freeing the user struct multiple times and triggering this +warning: + + refcount_t: underflow; use-after-free. + WARNING: CPU: 0 PID: 6794 at lib/refcount.c:288 refcount_dec_not_one+0x45/0x50 + Call Trace: + refcount_dec_and_lock_irqsave+0x16/0x60 + free_uid+0x31/0xa0 + __dequeue_signal+0x17c/0x190 + dequeue_signal+0x5a/0x1b0 + do_sigtimedwait+0x208/0x250 + __x64_sys_rt_sigtimedwait+0x6f/0xd0 + do_syscall_64+0x72/0x200 + entry_SYSCALL_64_after_hwframe+0x49/0xbe + +Signed-off-by: Matt Fleming +Reported-by: Daniel Wagner +Signed-off-by: Sebastian Andrzej Siewior +Signed-off-by: Tom Zanussi +--- + kernel/signal.c | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +diff --git a/kernel/signal.c b/kernel/signal.c +index 74f807bba0b8..59294dfaa744 100644 +--- a/kernel/signal.c ++++ b/kernel/signal.c +@@ -489,8 +489,8 @@ static void sigqueue_free_current(struct sigqueue *q) + + up = q->user; + if (rt_prio(current->normal_prio) && !put_task_cache(current, q)) { +- atomic_dec(&up->sigpending); +- free_uid(up); ++ if (atomic_dec_and_test(&up->sigpending)) ++ free_uid(up); + } else + __sigqueue_free(q); + } +-- +2.36.1 + -- cgit v1.2.3