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| author | Mel Gorman <mgorman@techsingularity.net> | 2025-01-23 22:11:13 +0000 |
|---|---|---|
| committer | Kees Cook <kees@kernel.org> | 2025-02-28 11:51:31 -0800 |
| commit | d2132f453e3308adc82ab7c101bd5220a9a34167 (patch) | |
| tree | 4971a7438d70cdff1ac07fec100879a45a28af89 | |
| parent | f4d4e8b9d6afe880a855e919c4ba4139455e11db (diff) | |
| download | linux-d2132f453e3308adc82ab7c101bd5220a9a34167.tar.gz linux-d2132f453e3308adc82ab7c101bd5220a9a34167.tar.bz2 linux-d2132f453e3308adc82ab7c101bd5220a9a34167.zip | |
mm: security: Allow default HARDENED_USERCOPY to be set at compile time
HARDENED_USERCOPY defaults to on if enabled at compile time. Allow
hardened_usercopy= default to be set at compile time similar to
init_on_alloc= and init_on_free=. The intent is that hardening
options that can be disabled at runtime can set their default at
build time.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Link: https://lore.kernel.org/r/20250123221115.19722-3-mgorman@techsingularity.net
Signed-off-by: Kees Cook <kees@kernel.org>
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 4 | ||||
| -rw-r--r-- | mm/usercopy.c | 3 | ||||
| -rw-r--r-- | security/Kconfig.hardening | 8 |
3 files changed, 13 insertions, 2 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index fb8752b42ec8..41d4cf206ec1 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1785,7 +1785,9 @@ allocation boundaries as a proactive defense against bounds-checking flaws in the kernel's copy_to_user()/copy_from_user() interface. - on Perform hardened usercopy checks (default). + The default is determined by + CONFIG_HARDENED_USERCOPY_DEFAULT_ON. + on Perform hardened usercopy checks. off Disable hardened usercopy checks. hardlockup_all_cpu_backtrace= diff --git a/mm/usercopy.c b/mm/usercopy.c index 16d63bd010af..e65a612ce8e8 100644 --- a/mm/usercopy.c +++ b/mm/usercopy.c @@ -255,7 +255,8 @@ void __check_object_size(const void *ptr, unsigned long n, bool to_user) } EXPORT_SYMBOL(__check_object_size); -static bool enable_checks __initdata = true; +static bool enable_checks __initdata = + IS_ENABLED(CONFIG_HARDENED_USERCOPY_DEFAULT_ON); static int __init parse_hardened_usercopy(char *str) { diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index 9f1bea733523..45748379f896 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -294,6 +294,14 @@ config HARDENED_USERCOPY or are part of the kernel text. This prevents entire classes of heap overflow exploits and similar kernel memory exposures. +config HARDENED_USERCOPY_DEFAULT_ON + bool "Harden memory copies by default" + depends on HARDENED_USERCOPY + default HARDENED_USERCOPY + help + This has the effect of setting "hardened_usercopy=on" on the kernel + command line. This can be disabled with "hardened_usercopy=off". + endmenu menu "Hardening of kernel data structures" |