Add a new Kconfig option CONFIG_BPF_JIT_KASAN that automatically enables generic KASAN (Kernel Address SANitizer) memory access checks for JIT-compiled BPF programs as well, when both KASAN (and more specifically, generic KASAN with KASAN_VMALLOC) and JIT compiler are enabled. This new Kconfig is not a user selectable one: it is automatically enabled if KASAN is enabled on a compatible platform. When enabled, the JIT compiler will emit shadow memory checks before memory loads and stores to detect use-after-free or out-of-bounds accesses at runtime. The option is gated behind HAVE_EBPF_JIT_KASAN, as it needs proper arch-specific implementation.
Acked-by: Andrey Konovalov <[email protected]> Acked-by: Ihor Solodrai <[email protected]> Signed-off-by: Alexis Lothoré (eBPF Foundation) <[email protected]> --- Changes in v6: - fix commit msg - get rid of "if KASAN" when setting default value, already implied by KASAN_GENERIC Changes in v4: - reorganize dependencies (Andrey) - drop VMAP_STACK dependency Changes in v2: - add dependency on kasan for vmalloc and vmalloc'ed stack --- kernel/bpf/Kconfig | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig index eb3de35734f0..d7d25477ef48 100644 --- a/kernel/bpf/Kconfig +++ b/kernel/bpf/Kconfig @@ -17,6 +17,10 @@ config HAVE_CBPF_JIT config HAVE_EBPF_JIT bool +# KASAN support for JIT compiler +config HAVE_EBPF_JIT_KASAN + bool + # Used by archs to tell that they want the BPF JIT compiler enabled by # default for kernels that were compiled with BPF JIT support. config ARCH_WANT_DEFAULT_BPF_JIT @@ -101,4 +105,17 @@ config BPF_LSM If you are unsure how to answer this question, answer N. +config BPF_JIT_KASAN + bool + depends on HAVE_EBPF_JIT_KASAN + depends on KASAN_GENERIC + depends on KASAN_VMALLOC + depends on BPF_JIT + default y + help + Makes JIT compiler insert generic outline KASAN checks in BPF + programs when they are inserted in the kernel. This feature is + automatically enabled if the needed set of KASAN and BPF + configuration options is enabled. + endmenu # "BPF subsystem" -- 2.55.0
