From: Christoph Hellwig <hch@lst.de>
To: Nick Hu <nickhu@andestech.com>, Greentime Hu <green.hu@gmail.com>,
Vincent Chen <deanbo422@gmail.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org, linux-riscv@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 6/6] exec: use force_uaccess_begin during exec and exit
Date: Fri, 10 Jul 2020 15:57:06 +0200 [thread overview]
Message-ID: <20200710135706.537715-7-hch@lst.de> (raw)
In-Reply-To: <20200710135706.537715-1-hch@lst.de>
Both exec and exit want to ensure that the uaccess routines actually do
access user pointers. Use the newly added force_uaccess_begin helper
instead of an open coded set_fs for that to prepare for kernel builds
where set_fs() does not exist.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/exec.c | 7 ++++++-
kernel/exit.c | 2 +-
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index e6e8a9a7032784..769af470b69124 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1380,7 +1380,12 @@ int begin_new_exec(struct linux_binprm * bprm)
if (retval)
goto out_unlock;
- set_fs(USER_DS);
+ /*
+ * Ensure that the uaccess routines can actually operate on userspace
+ * pointers:
+ */
+ force_uaccess_begin();
+
me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD |
PF_NOFREEZE | PF_NO_SETAFFINITY);
flush_thread();
diff --git a/kernel/exit.c b/kernel/exit.c
index 727150f2810338..17d486a20f0dc6 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -731,7 +731,7 @@ void __noreturn do_exit(long code)
* mm_release()->clear_child_tid() from writing to a user-controlled
* kernel address.
*/
- set_fs(USER_DS);
+ force_uaccess_begin();
if (unlikely(in_atomic())) {
pr_info("note: %s[%d] exited with preempt_count %d\n",
--
2.26.2
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next prev parent reply other threads:[~2020-07-10 13:57 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-10 13:57 clean up address limit helpers Christoph Hellwig
2020-07-10 13:57 ` [PATCH 1/6] syscalls: use uaccess_kernel in addr_limit_user_check Christoph Hellwig
2020-07-10 13:57 ` [PATCH 2/6] nds32: use uaccess_kernel in show_regs Christoph Hellwig
2020-07-13 10:02 ` Greentime Hu
2020-07-10 13:57 ` [PATCH 3/6] riscv: include <asm/pgtable.h> in <asm/uaccess.h> Christoph Hellwig
2020-07-21 23:02 ` Palmer Dabbelt
2020-07-10 13:57 ` [PATCH 4/6] uaccess: remove segment_eq Christoph Hellwig
2020-07-13 9:16 ` Geert Uytterhoeven
2020-07-13 10:05 ` Greentime Hu
2020-07-10 13:57 ` [PATCH 5/6] uaccess: add force_uaccess_{begin,end} helpers Christoph Hellwig
2020-07-13 9:12 ` Geert Uytterhoeven
2020-07-13 10:06 ` Greentime Hu
2020-07-13 12:21 ` Mark Rutland
2020-07-13 13:19 ` Geert Uytterhoeven
2020-07-14 7:12 ` Christoph Hellwig
2020-07-13 12:26 ` Mark Rutland
2020-07-10 13:57 ` Christoph Hellwig [this message]
2020-07-10 15:25 ` clean up address limit helpers Linus Torvalds
2020-07-14 7:09 ` Christoph Hellwig
2020-07-14 15:33 ` Linus Torvalds
2020-07-14 10:54 clean up address limit helpers v2 Christoph Hellwig
2020-07-14 10:55 ` [PATCH 6/6] exec: use force_uaccess_begin during exec and exit Christoph Hellwig
2020-07-15 3:33 ` Eric W. Biederman
2020-07-15 6:06 ` Christoph Hellwig
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