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Message-Id: <20210114172338.2798389-9-lenaptr@google.com>
Date: Thu, 14 Jan 2021 17:23:38 +0000
From: Elena Petrova <lenaptr@...gle.com>
To: kvmarm@...ts.cs.columbia.edu
Cc: Elena Petrova <lenaptr@...gle.com>,
linux-arm-kernel@...ts.infradead.org,
open list <linux-kernel@...r.kernel.org>,
Marc Zyngier <maz@...nel.org>,
James Morse <james.morse@....com>,
Julien Thierry <julien.thierry.kdev@...il.com>,
Suzuki K Poulose <suzuki.poulose@....com>,
George Popescu <george.apopescu97@...il.com>,
George Popescu <georgepope@...gle.com>
Subject: [PATCH v2 8/9] KVM: arm64: Detect arithmetic overflow is inside hyp/nVHE.
From: George Popescu <georgepope@...gle.com>
Whenever an arithmetic overflow: addition, substraction, multiplication,
division or negating happens inside the hyp/nVHE code,
an __ubsan_handle_*_overflow is called.
All the overflow handlers are sharing the same structure called
overflow_data.
Signed-off-by: George Popescu <georgepope@...gle.com>
Change-Id: Iec1ef331e471efbb35a39ffaee0641107a3a0e3a
Signed-off-by: Elena Petrova <lenaptr@...gle.com>
---
arch/arm64/include/asm/kvm_ubsan.h | 10 ++++++--
arch/arm64/kvm/hyp/nvhe/ubsan.c | 40 ++++++++++++++++++++++++++----
arch/arm64/kvm/kvm_ubsan_buffer.c | 20 ++++++++++++++-
3 files changed, 62 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_ubsan.h b/arch/arm64/include/asm/kvm_ubsan.h
index 93c1b695097a..da4a3b4e28e0 100644
--- a/arch/arm64/include/asm/kvm_ubsan.h
+++ b/arch/arm64/include/asm/kvm_ubsan.h
@@ -22,7 +22,8 @@ struct kvm_ubsan_info {
UBSAN_UNREACHABLE_DATA,
UBSAN_SHIFT_OUT_OF_BOUNDS,
UBSAN_INVALID_DATA,
- UBSAN_TYPE_MISMATCH
+ UBSAN_TYPE_MISMATCH,
+ UBSAN_OVERFLOW_DATA
} type;
union {
struct out_of_bounds_data out_of_bounds_data;
@@ -30,6 +31,7 @@ struct kvm_ubsan_info {
struct shift_out_of_bounds_data shift_out_of_bounds_data;
struct invalid_value_data invalid_value_data;
struct type_mismatch_data type_mismatch_data;
+ struct overflow_data overflow_data;
};
union {
struct ubsan_values u_val;
@@ -41,4 +43,8 @@ void __ubsan_handle_builtin_unreachable(void *_data);
void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs);
void __ubsan_handle_load_invalid_value(void *_data, void *val);
void __ubsan_handle_type_mismatch(struct type_mismatch_data *_data, void *ptr);
-
+void __ubsan_handle_add_overflow(void *data, void *lhs, void *rhs);
+void __ubsan_handle_sub_overflow(void *data, void *lhs, void *rhs);
+void __ubsan_handle_mul_overflow(void *data, void *lhs, void *rhs);
+void __ubsan_handle_negate_overflow(void *_data, void *old_val);
+void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs);
diff --git a/arch/arm64/kvm/hyp/nvhe/ubsan.c b/arch/arm64/kvm/hyp/nvhe/ubsan.c
index a9f72d4bcab7..f16842ff7316 100644
--- a/arch/arm64/kvm/hyp/nvhe/ubsan.c
+++ b/arch/arm64/kvm/hyp/nvhe/ubsan.c
@@ -47,15 +47,45 @@ static void write_type_mismatch_data(struct type_mismatch_data_common *data, voi
}
}
-void __ubsan_handle_add_overflow(void *_data, void *lhs, void *rhs) {}
+static void write_overflow_data(struct overflow_data *data, void *lval, void *rval, char op)
+{
+ struct kvm_ubsan_info *slot = kvm_ubsan_buffer_next_slot();
+
+ if (slot) {
+ slot->type = UBSAN_OVERFLOW_DATA;
+ slot->overflow_data = *data;
+ slot->u_val.op = op;
+ slot->u_val.lval = lval;
+ if (op != '!')
+ slot->u_val.rval = rval;
+ }
+}
+
+void __ubsan_handle_add_overflow(void *_data, void *lhs, void *rhs)
+{
+ write_overflow_data(_data, lhs, rhs, '+');
+}
-void __ubsan_handle_sub_overflow(void *_data, void *lhs, void *rhs) {}
+void __ubsan_handle_sub_overflow(void *_data, void *lhs, void *rhs)
+{
+ write_overflow_data(_data, lhs, rhs, '-');
+}
-void __ubsan_handle_mul_overflow(void *_data, void *lhs, void *rhs) {}
+void __ubsan_handle_mul_overflow(void *_data, void *lhs, void *rhs)
+{
+ write_overflow_data(_data, lhs, rhs, '*');
+}
-void __ubsan_handle_negate_overflow(void *_data, void *old_val) {}
+void __ubsan_handle_negate_overflow(void *_data, void *old_val)
+{
+ write_overflow_data(_data, old_val, NULL, '!');
+}
+
+void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs)
+{
+ write_overflow_data(_data, lhs, rhs, '/');
+}
-void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs) {}
void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr)
{
diff --git a/arch/arm64/kvm/kvm_ubsan_buffer.c b/arch/arm64/kvm/kvm_ubsan_buffer.c
index b7823dedf8b1..2c7060cbb48b 100644
--- a/arch/arm64/kvm/kvm_ubsan_buffer.c
+++ b/arch/arm64/kvm/kvm_ubsan_buffer.c
@@ -39,7 +39,25 @@ void __kvm_check_ubsan_data(struct kvm_ubsan_info *slot)
__ubsan_handle_type_mismatch(&slot->type_mismatch_data,
slot->u_val.lval);
break;
- }
+ case UBSAN_OVERFLOW_DATA:
+ if (slot->u_val.op == '/') {
+ __ubsan_handle_divrem_overflow(&slot->overflow_data,
+ slot->u_val.lval, slot->u_val.rval);
+ } else if (slot->u_val.op == '!') {
+ __ubsan_handle_negate_overflow(&slot->overflow_data,
+ slot->u_val.lval);
+ } else if (slot->u_val.op == '+') {
+ __ubsan_handle_add_overflow(&slot->overflow_data,
+ slot->u_val.lval, slot->u_val.rval);
+ } else if (slot->u_val.op == '-') {
+ __ubsan_handle_sub_overflow(&slot->overflow_data,
+ slot->u_val.lval, slot->u_val.rval);
+ } else if (slot->u_val.op == '*') {
+ __ubsan_handle_mul_overflow(&slot->overflow_data,
+ slot->u_val.lval, slot->u_val.rval);
+ }
+ break;
+ }
}
void iterate_kvm_ubsan_buffer(unsigned long left, unsigned long right)
--
2.30.0.284.gd98b1dd5eaa7-goog
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