[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20190726133936.11177-72-sashal@kernel.org>
Date: Fri, 26 Jul 2019 09:39:22 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Peter Zijlstra <peterz@...radead.org>,
Vegard Nossum <vegard.nossum@...cle.com>,
Eiichi Tsukata <devel@...ukata.com>,
Thomas Gleixner <tglx@...utronix.de>,
Joel Fernandes <joel@...lfernandes.org>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 5.2 72/85] stacktrace: Force USER_DS for stack_trace_save_user()
From: Peter Zijlstra <peterz@...radead.org>
[ Upstream commit cac9b9a4b08304f11daace03b8b48659355e44c1 ]
When walking userspace stacks, USER_DS needs to be set, otherwise
access_ok() will not function as expected.
Reported-by: Vegard Nossum <vegard.nossum@...cle.com>
Reported-by: Eiichi Tsukata <devel@...ukata.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Tested-by: Vegard Nossum <vegard.nossum@...cle.com>
Reviewed-by: Joel Fernandes (Google) <joel@...lfernandes.org>
Link: https://lkml.kernel.org/r/20190718085754.GM3402@hirez.programming.kicks-ass.net
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
kernel/stacktrace.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index 36139de0a3c4..899b726c9e98 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -226,12 +226,17 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
.store = store,
.size = size,
};
+ mm_segment_t fs;
/* Trace user stack if not a kernel thread */
if (!current->mm)
return 0;
+ fs = get_fs();
+ set_fs(USER_DS);
arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
+ set_fs(fs);
+
return c.len;
}
#endif
--
2.20.1
Powered by blists - more mailing lists