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| author |  Chang S. Bae <chang.seok.bae@intel.com>
| 2021-05-18 13:03:17 -0700 |
|---|---|---|
| committer |  Borislav Petkov <bp@suse.de>
| 2021-05-19 12:18:45 +0200 |
| commit | 1c33bb0507508af24fd754dd7123bd8e997fab2f (patch) | |
| tree | 0a245b44e47ae22c57669af809f34ff1d9549314 /arch/x86/kernel/signal.c | |
| parent | x86/signal: Introduce helpers to get the maximum signal frame size (diff) | |
| download | linux-1c33bb0507508af24fd754dd7123bd8e997fab2f.tar.gz linux-1c33bb0507508af24fd754dd7123bd8e997fab2f.tar.bz2 linux-1c33bb0507508af24fd754dd7123bd8e997fab2f.zip | |
x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ
Historically, signal.h defines MINSIGSTKSZ (2KB) and SIGSTKSZ (8KB), for
use by all architectures with sigaltstack(2). Over time, the hardware state
size grew, but these constants did not evolve. Today, literal use of these
constants on several architectures may result in signal stack overflow, and
thus user data corruption.
A few years ago, the ARM team addressed this issue by establishing
getauxval(AT_MINSIGSTKSZ). This enables the kernel to supply a value
at runtime that is an appropriate replacement on current and future
hardware.
Add getauxval(AT_MINSIGSTKSZ) support to x86, analogous to the support
added for ARM in
94b07c1f8c39 ("arm64: signal: Report signal frame size to userspace via auxv").
Also, include a documentation to describe x86-specific auxiliary vectors.
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Len Brown <len.brown@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20210518200320.17239-4-chang.seok.bae@intel.com
Diffstat (limited to 'arch/x86/kernel/signal.c')
| -rw-r--r-- | arch/x86/kernel/signal.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 689a4b6dd18f..86e53868159a 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -718,6 +718,11 @@ void __init init_sigframe_size(void) pr_info("max sigframe size: %lu\n", max_frame_size); } +unsigned long get_sigframe_size(void) +{ + return max_frame_size; +} + static inline int is_ia32_compat_frame(struct ksignal *ksig) { return IS_ENABLED(CONFIG_IA32_EMULATION) && |