From mboxrd@z Thu Jan 1 00:00:00 1970 From: keescook@chromium.org (Kees Cook) Date: Thu, 7 Sep 2017 08:30:47 -0700 Subject: [PATCH 4/4] arm64/syscalls: Move address limit check in loop In-Reply-To: <1504798247-48833-1-git-send-email-keescook@chromium.org> References: <1504798247-48833-1-git-send-email-keescook@chromium.org> Message-ID: <1504798247-48833-5-git-send-email-keescook@chromium.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Thomas Garnier A bug was reported on ARM where set_fs might be called after it was checked on the work pending function. ARM64 is not affected by this bug but has a similar construct. In order to avoid any similar problems in the future, the addr_limit_user_check function is moved at the beginning of the loop. Fixes: cf7de27ab351 ("arm64/syscalls: Check address limit on user-mode return") Reported-by: Leonard Crestez Signed-off-by: Thomas Garnier Signed-off-by: Kees Cook --- arch/arm64/kernel/signal.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index c45214f8fb54..0bdc96c61bc0 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -751,10 +751,10 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, */ trace_hardirqs_off(); - /* Check valid user FS if needed */ - addr_limit_user_check(); - do { + /* Check valid user FS if needed */ + addr_limit_user_check(); + if (thread_flags & _TIF_NEED_RESCHED) { schedule(); } else { -- 2.7.4