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Groups > linux.kernel > #1620558
| From | tip-bot for Thomas Gleixner <tipbot@zytor.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [tip:x86/urgent] x86/vdso: Plug race between mapping and ELF header setup |
| Date | 2017-04-10 20:00 +0200 |
| Message-ID | <tuLLB-3YK-59@gated-at.bofh.it> (permalink) |
| References | <tuJgK-2nZ-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Commit-ID: 6fdc6dd90272ce7e75d744f71535cfbd8d77da81
Gitweb: http://git.kernel.org/tip/6fdc6dd90272ce7e75d744f71535cfbd8d77da81
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Mon, 10 Apr 2017 17:14:28 +0200
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 10 Apr 2017 18:31:41 +0200
x86/vdso: Plug race between mapping and ELF header setup
The vsyscall32 sysctl can racy against a concurrent fork when it switches
from disabled to enabled:
arch_setup_additional_pages()
if (vdso32_enabled)
--> No mapping
sysctl.vsysscall32()
--> vdso32_enabled = true
create_elf_tables()
ARCH_DLINFO_IA32
if (vdso32_enabled) {
--> Add VDSO entry with NULL pointer
Make ARCH_DLINFO_IA32 check whether the VDSO mapping has been set up for
the newly forked process or not.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20170410151723.602367196@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/elf.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 9d49c18..3762536 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -287,7 +287,7 @@ struct task_struct;
#define ARCH_DLINFO_IA32 \
do { \
- if (vdso32_enabled) { \
+ if (VDSO_CURRENT_BASE) { \
NEW_AUX_ENT(AT_SYSINFO, VDSO_ENTRY); \
NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_CURRENT_BASE); \
} \
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[patch 0/3] x86/vdso: Fix enable inconsistencies and cleanup Thomas Gleixner <tglx@linutronix.de> - 2017-04-10 17:20 +0200
[patch 2/3] x86/vdso: Plug race between mapping and ELF header setup Thomas Gleixner <tglx@linutronix.de> - 2017-04-10 17:20 +0200
Re: [patch 2/3] x86/vdso: Plug race between mapping and ELF header setup Andy Lutomirski <luto@amacapital.net> - 2017-04-10 18:00 +0200
[tip:x86/urgent] x86/vdso: Plug race between mapping and ELF header setup tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-04-10 20:00 +0200
[patch 3/3] x86/vdso: Sanitize vdso*_enabled handling Thomas Gleixner <tglx@linutronix.de> - 2017-04-10 17:20 +0200
Re: [patch 3/3] x86/vdso: Sanitize vdso*_enabled handling Andy Lutomirski <luto@amacapital.net> - 2017-04-10 18:00 +0200
Re: [patch 3/3] x86/vdso: Sanitize vdso*_enabled handling Thomas Gleixner <tglx@linutronix.de> - 2017-04-10 18:30 +0200
[patch 1/3] x86/vdso: Ensure vdso32_enabled gets set to valid values only Thomas Gleixner <tglx@linutronix.de> - 2017-04-10 17:20 +0200
[tip:x86/urgent] x86/vdso: Ensure vdso32_enabled gets set to valid values only tip-bot for Mathias Krause <tipbot@zytor.com> - 2017-04-10 18:40 +0200
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