From dd69edd643a8263f9a96d0a3a82d8d50d9df9b48 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Mon, 26 Feb 2024 17:56:50 +0100 Subject: get_signal: hide_si_addr_tag_bits: fix the usage of uninitialized ksig ksig->ka and ksig->info are not initialized if get_signal() returns 0 or if the caller is PF_USER_WORKER. Check signr != 0 before SA_EXPOSE_TAGBITS and move the "out" label down. The latter means that ksig->sig won't be initialized if a PF_USER_WORKER thread gets a fatal signal but this is fine, PF_USER_WORKER's don't use ksig. And there is nothing new, in this case ksig->ka and ksig-info are not initialized anyway. Add a comment. Link: https://lkml.kernel.org/r/20240226165650.GA20829@redhat.com Signed-off-by: Oleg Nesterov Cc: Christian Brauner Cc: Eric W. Biederman Cc: Peter Collingbourne Cc: Wen Yang Signed-off-by: Andrew Morton --- kernel/signal.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index 09a6dd07cf6b..a69d3069067a 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2881,8 +2881,9 @@ relock: /* * PF_USER_WORKER threads will catch and exit on fatal signals - * themselves. They have cleanup that must be performed, so - * we cannot call do_exit() on their behalf. + * themselves. They have cleanup that must be performed, so we + * cannot call do_exit() on their behalf. Note that ksig won't + * be properly initialized, PF_USER_WORKER's shouldn't use it. */ if (current->flags & PF_USER_WORKER) goto out; @@ -2894,12 +2895,12 @@ relock: /* NOTREACHED */ } spin_unlock_irq(&sighand->siglock); -out: + ksig->sig = signr; - if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS)) + if (signr && !(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS)) hide_si_addr_tag_bits(ksig); - +out: return signr > 0; } -- cgit v1.2.3