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| author | Thomas Gleixner <tglx@linutronix.de> | 2021-10-22 00:55:06 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-10-26 10:18:09 +0200 |
| commit | 3aac3ebea08f2d342364f827c8979ab0e1dd591e (patch) | |
| tree | 66cfbec408ebb30544063cde4b49094da02c6d66 /Documentation/admin-guide | |
| parent | signal: Add an optional check for altstack size (diff) | |
| download | linux-3aac3ebea08f2d342364f827c8979ab0e1dd591e.tar.xz linux-3aac3ebea08f2d342364f827c8979ab0e1dd591e.zip | |
x86/signal: Implement sigaltstack size validation
For historical reasons MINSIGSTKSZ is a constant which became already too
small with AVX512 support.
Add a mechanism to enforce strict checking of the sigaltstack size against
the real size of the FPU frame.
The strict check can be enabled via a config option and can also be
controlled via the kernel command line option 'strict_sas_size' independent
of the config switch.
Enabling it might break existing applications which allocate a too small
sigaltstack but 'work' because they never get a signal delivered. Though it
can be handy to filter out binaries which are not yet aware of
AT_MINSIGSTKSZ.
Also the upcoming support for dynamically enabled FPU features requires a
strict sanity check to ensure that:
- Enabling of a dynamic feature, which changes the sigframe size fits
into an enabled sigaltstack
- Installing a too small sigaltstack after a dynamic feature has been
added is not possible.
Implement the base check which is controlled by config and command line
options.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211021225527.10184-3-chang.seok.bae@intel.com
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 43dc35fe5bc0..eb9a73ad91a0 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5497,6 +5497,15 @@ stifb= [HW] Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]] + strict_sas_size= + [X86] + Format: <bool> + Enable or disable strict sigaltstack size checks + against the required signal frame size which + depends on the supported FPU features. This can + be used to filter out binaries which have + not yet been made aware of AT_MINSIGSTKSZ. + sunrpc.min_resvport= sunrpc.max_resvport= [NFS,SUNRPC] |