Fix code that handles KVM_SET_ONE_REG, KVM_GET_ONE_REG ioctls to work in BE
image. Before this fix get/set_one_reg functions worked correctly only in
LE case - reg_from_user was taking 'void *' kernel address that actually could
be target/source memory of either 4 bytes size or 8 bytes size, and code copied
from/to user memory that could hold either 4 bytes register, 8 byte register
or pair of 4 bytes registers.
In order to work in endian agnostic way we will enforce rule that reg_from_user
to reg_to_user can copy register value only to kernel variable with size that
matches register size. For this purpose change functions to macros that check
sizeof(*val) against register size.
In few place where size mismatch existed fix issue on macro caller side.
Signed-off-by: Victor Kamensky <victor.kamensky@xxxxxxxxxx>
---
arch/arm/kvm/coproc.c | 95 +++++++++++++++++++++++++++++++++++++++------------
1 file changed, 74 insertions(+), 21 deletions(-)
diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c
index c58a351..5d45be5 100644
--- a/arch/arm/kvm/coproc.c
+++ b/arch/arm/kvm/coproc.c
@@ -682,26 +682,43 @@ static struct coproc_reg invariant_cp15[] = {
{ CRn( 0), CRm( 0), Op1( 1), Op2( 7), is32, NULL, get_AIDR },
};
-static int reg_from_user(void *val, const void __user *uaddr, u64 id)
-{
- /* This Just Works because we are little endian. */
- if (copy_from_user(val, uaddr, KVM_REG_SIZE(id)) != 0)
- return -EFAULT;
- return 0;
-}
+/*
+ * Reads a register value from a userspace address to a kernel
+ * variable. Note register size must match sizeof(*__val).
+ */
+#define reg_from_user(__val, __uaddr, __id) ({ \
+ int __ret = 0; \
+ unsigned long __regsize = KVM_REG_SIZE(__id); \
+ if (sizeof(*(__val)) != __regsize) { \
+ __ret = -ENOENT; \
+ } else { \
+ if (copy_from_user((__val), (__uaddr), __regsize) != 0) \
+ __ret = -EFAULT; \
+ } \
+ __ret; \
+})
-static int reg_to_user(void __user *uaddr, const void *val, u64 id)
-{
- /* This Just Works because we are little endian. */
- if (copy_to_user(uaddr, val, KVM_REG_SIZE(id)) != 0)
- return -EFAULT;
- return 0;
-}
+/*
+ * Writes a register value to a userspace address from a kernel variable.
+ * Note register size must match sizeof(*__val).
+ */
+#define reg_to_user(__uaddr, __val, __id) ({ \
+ int __ret = 0; \
+ unsigned long __regsize = KVM_REG_SIZE(__id); \
+ if (sizeof(*(__val)) != __regsize) { \
+ __ret = -ENOENT; \
+ } else { \
+ if (copy_to_user((__uaddr), (__val), __regsize) != 0) \
+ __ret = -EFAULT; \
+ } \
+ __ret; \
+})
static int get_invariant_cp15(u64 id, void __user *uaddr)
{
struct coproc_params params;
const struct coproc_reg *r;
+ int ret;
if (!index_to_params(id, ¶ms))
return -ENOENT;
@@ -710,7 +727,14 @@ static int get_invariant_cp15(u64 id, void __user *uaddr)
if (!r)
return -ENOENT;
- return reg_to_user(uaddr, &r->val, id);
+ ret = -ENOENT;
+ if (KVM_REG_SIZE(id) == 4) {
+ u32 val = r->val;
+ ret = reg_to_user(uaddr, &val, id);
+ } else if (KVM_REG_SIZE(id) == 8) {
+ ret = reg_to_user(uaddr, &r->val, id);
+ }
+ return ret;
}
static int set_invariant_cp15(u64 id, void __user *uaddr)
@@ -718,7 +742,7 @@ static int set_invariant_cp15(u64 id, void __user *uaddr)
struct coproc_params params;
const struct coproc_reg *r;
int err;
- u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
+ u64 val;
if (!index_to_params(id, ¶ms))
return -ENOENT;
@@ -726,7 +750,15 @@ static int set_invariant_cp15(u64 id, void __user *uaddr)
if (!r)
return -ENOENT;
- err = reg_from_user(&val, uaddr, id);
+ err = -ENOENT;
+ if (KVM_REG_SIZE(id) == 4) {
+ u32 val32;
+ err = reg_from_user(&val32, uaddr, id);
+ if (!err)
+ val = val32;
+ } else if (KVM_REG_SIZE(id) == 8) {
+ err = reg_from_user(&val, uaddr, id);
+ }
if (err)
return err;
@@ -1004,6 +1036,7 @@ int kvm_arm_coproc_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
const struct coproc_reg *r;
void __user *uaddr = (void __user *)(long)reg->addr;
+ int ret;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
return demux_c15_get(reg->id, uaddr);
@@ -1015,14 +1048,24 @@ int kvm_arm_coproc_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
if (!r)
return get_invariant_cp15(reg->id, uaddr);
- /* Note: copies two regs if size is 64 bit. */
- return reg_to_user(uaddr, &vcpu->arch.cp15[r->reg], reg->id);
+ ret = -ENOENT;
+ if (KVM_REG_SIZE(reg->id) == 8) {
+ u64 val;
+ /* Note: copies two u32 regs */
+ memcpy(&val, &(vcpu->arch.cp15[r->reg]), sizeof(val));
+ ret = reg_to_user(uaddr, &val, reg->id);
+ } else if (KVM_REG_SIZE(reg->id) == 4) {
+ ret = reg_to_user(uaddr, &vcpu->arch.cp15[r->reg], reg->id);
+ }
+
+ return ret;
}
int kvm_arm_coproc_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
const struct coproc_reg *r;
void __user *uaddr = (void __user *)(long)reg->addr;
+ int ret;
if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
return demux_c15_set(reg->id, uaddr);
@@ -1034,8 +1077,18 @@ int kvm_arm_coproc_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
if (!r)
return set_invariant_cp15(reg->id, uaddr);
- /* Note: copies two regs if size is 64 bit */
- return reg_from_user(&vcpu->arch.cp15[r->reg], uaddr, reg->id);
+ ret = -ENOENT;
+ if (KVM_REG_SIZE(reg->id) == 8) {
+ u64 val;
+ /* Note: copies two u32 regs */
+ ret = reg_from_user(&val, uaddr, reg->id);
+ if (!ret)
+ memcpy(&(vcpu->arch.cp15[r->reg]), &val, sizeof(val));
+ } else if (KVM_REG_SIZE(reg->id) == 4) {
+ ret = reg_from_user(&vcpu->arch.cp15[r->reg], uaddr, reg->id);
+ }
+
+ return ret;
}
static unsigned int num_demux_regs(void)
--
1.8.1.4
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