diff options
| author |   Catalin Marinas <catalin.marinas@arm.com> | 2019-07-23 19:58:39 +0200 |
|---|---|---|
| committer |   Will Deacon <will@kernel.org> | 2019-08-06 18:08:45 +0100 |
| commit | 63f0c60379650d82250f22e4cf4137ef3dc4f43d (patch) | |
| tree | af76cdc5d0eeca023d86c43664d073af25d63546 /arch/arm64/Kconfig | |
| parent | arm64: untag user pointers in access_ok and __uaccess_mask_ptr (diff) | |
| download | linux-dev-63f0c60379650d82250f22e4cf4137ef3dc4f43d.tar.xz linux-dev-63f0c60379650d82250f22e4cf4137ef3dc4f43d.zip | |
arm64: Introduce prctl() options to control the tagged user addresses ABI
It is not desirable to relax the ABI to allow tagged user addresses into
the kernel indiscriminately. This patch introduces a prctl() interface
for enabling or disabling the tagged ABI with a global sysctl control
for preventing applications from enabling the relaxed ABI (meant for
testing user-space prctl() return error checking without reconfiguring
the kernel). The ABI properties are inherited by threads of the same
application and fork()'ed children but cleared on execve(). A Kconfig
option allows the overall disabling of the relaxed ABI.
The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
MTE-specific settings like imprecise vs precise exceptions.
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to '')
| -rw-r--r-- | arch/arm64/Kconfig | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 3adcec05b1f6..5d254178b9ca 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1110,6 +1110,15 @@ config ARM64_SW_TTBR0_PAN zeroed area and reserved ASID. The user access routines restore the valid TTBR0_EL1 temporarily. +config ARM64_TAGGED_ADDR_ABI + bool "Enable the tagged user addresses syscall ABI" + default y + help + When this option is enabled, user applications can opt in to a + relaxed ABI via prctl() allowing tagged addresses to be passed + to system calls as pointer arguments. For details, see + Documentation/arm64/tagged-address-abi.txt. + menuconfig COMPAT bool "Kernel support for 32-bit EL0" depends on ARM64_4K_PAGES || EXPERT |