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Code Issues Releases Wiki Activity

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 <oleg@redhat.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Wen Yang <wenyang.linux@foxmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2024-02-26 17:56:50 +01:00 committed by Andrew Morton
parent 49fd5f5ac4
commit dd69edd643
1 changed files with 6 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
kernel/signal.c
View File

@ -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;
}