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Subject[PATCH v2 3/9] KVM: arm64: Enable UBSAN_BOUNDS for the both the kernel and hyp/nVHE
From
From: George Popescu <georgepope@google.com>

If an out of bounds happens inside the hyp/nVHE code, the ubsan_out_of_bounds
handler stores the logging data inside the kvm_ubsan_buffer. The one responsible
for printing is the kernel ubsan_out_of_bounds handler. The process of
decapsulating the data from the buffer is straightforward.

Signed-off-by: George Popescu <georgepope@google.com>
Signed-off-by: Elena Petrova <lenaptr@google.com>
---
arch/arm64/include/asm/kvm_ubsan.h | 19 ++++++++++++++++++-
arch/arm64/kvm/hyp/nvhe/ubsan.c | 14 ++++++++++++--
arch/arm64/kvm/kvm_ubsan_buffer.c | 10 ++++++++++
3 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_ubsan.h b/arch/arm64/include/asm/kvm_ubsan.h
index fb32c7fd65d4..4f471acb88b0 100644
--- a/arch/arm64/include/asm/kvm_ubsan.h
+++ b/arch/arm64/include/asm/kvm_ubsan.h
@@ -9,6 +9,23 @@
#define UBSAN_MAX_TYPE 6
#define KVM_UBSAN_BUFFER_SIZE 1000

+
+struct ubsan_values {
+ void *lval;
+ void *rval;
+ char op;
+};
+
struct kvm_ubsan_info {
- int type;
+ enum {
+ UBSAN_OUT_OF_BOUNDS,
+ } type;
+ union {
+ struct out_of_bounds_data out_of_bounds_data;
+ };
+ union {
+ struct ubsan_values u_val;
+ };
};
+
+void __ubsan_handle_out_of_bounds(void *_data, void *index);
diff --git a/arch/arm64/kvm/hyp/nvhe/ubsan.c b/arch/arm64/kvm/hyp/nvhe/ubsan.c
index 8a194fb1f6cf..55a8f6db8555 100644
--- a/arch/arm64/kvm/hyp/nvhe/ubsan.c
+++ b/arch/arm64/kvm/hyp/nvhe/ubsan.c
@@ -13,7 +13,6 @@
#include <asm/kvm_ubsan.h>
#include <asm/kvm_debug_buffer.h>
#include <kvm/arm_pmu.h>
-#include <ubsan.h>

DEFINE_KVM_DEBUG_BUFFER(struct kvm_ubsan_info, kvm_ubsan_buffer,
kvm_ubsan_buff_wr_ind, KVM_UBSAN_BUFFER_SIZE);
@@ -44,7 +43,18 @@ void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr) {}

void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr) {}

-void __ubsan_handle_out_of_bounds(void *_data, void *index) {}
+void __ubsan_handle_out_of_bounds(void *_data, void *index)
+{
+ struct kvm_ubsan_info *slot;
+ struct out_of_bounds_data *data = _data;
+
+ slot = kvm_ubsan_buffer_next_slot();
+ if (slot) {
+ slot->type = UBSAN_OUT_OF_BOUNDS;
+ slot->out_of_bounds_data = *data;
+ slot->u_val.lval = index;
+ }
+}

void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs) {}

diff --git a/arch/arm64/kvm/kvm_ubsan_buffer.c b/arch/arm64/kvm/kvm_ubsan_buffer.c
index 4a1959ba9f68..a1523f86be3c 100644
--- a/arch/arm64/kvm/kvm_ubsan_buffer.c
+++ b/arch/arm64/kvm/kvm_ubsan_buffer.c
@@ -17,6 +17,15 @@
DECLARE_KVM_DEBUG_BUFFER(struct kvm_ubsan_info, kvm_ubsan_buffer,
kvm_ubsan_buff_wr_ind, KVM_UBSAN_BUFFER_SIZE);

+void __kvm_check_ubsan_data(struct kvm_ubsan_info *slot)
+{
+ switch (slot->type) {
+ case UBSAN_OUT_OF_BOUNDS:
+ __ubsan_handle_out_of_bounds(&slot->out_of_bounds_data,
+ slot->u_val.lval);
+ break;
+ }
+}

void iterate_kvm_ubsan_buffer(unsigned long left, unsigned long right)
{
@@ -26,6 +35,7 @@ void iterate_kvm_ubsan_buffer(unsigned long left, unsigned long right)
slot = (struct kvm_ubsan_info *) this_cpu_ptr_nvhe_sym(kvm_ubsan_buffer);
for (i = left; i < right; ++i) {
/* check ubsan data */
+ __kvm_check_ubsan_data(slot + i);
slot[i].type = 0;
}
}
--
2.30.0.284.gd98b1dd5eaa7-goog
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