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| author | Thomas Gleixner <tglx@linutronix.de> | 2017-04-10 17:14:28 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-07-18 18:38:42 +0100 |
| commit | df1c5dfda0b4ed3aa39b4450a2f67c4239d8fde4 (patch) | |
| tree | 56cede247b2c8bde8ae329e6fedcdc3e6d2bf88b /arch | |
| parent | 34b5dcc50abe6445aae34c7d055d70832a5951a7 (diff) | |
| download | linux-stable-df1c5dfda0b4ed3aa39b4450a2f67c4239d8fde4.tar.gz linux-stable-df1c5dfda0b4ed3aa39b4450a2f67c4239d8fde4.tar.bz2 linux-stable-df1c5dfda0b4ed3aa39b4450a2f67c4239d8fde4.zip | |
x86/vdso: Plug race between mapping and ELF header setup
commit 6fdc6dd90272ce7e75d744f71535cfbd8d77da81 upstream.
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>
Link: http://lkml.kernel.org/r/20170410151723.602367196@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bwh: Backported to 3.2: change the flag passed to ARCH_DLINFO_IA32()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/elf.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index 5f962df30d0f..81a156923b61 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -298,7 +298,7 @@ do { \ #define AT_SYSINFO 32 -#define COMPAT_ARCH_DLINFO ARCH_DLINFO_IA32(sysctl_vsyscall32) +#define COMPAT_ARCH_DLINFO ARCH_DLINFO_IA32(VDSO_CURRENT_BASE) #define COMPAT_ELF_ET_DYN_BASE (TASK_UNMAPPED_BASE + 0x1000000) |