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KVM: arm64: vgic-its: Remove VLA usage 

In the quest to remove all stack VLA usage from the kernel[1], this
switches to using a maximum size and adds sanity checks. Additionally
cleans up some of the int-vs-u32 usage and adds additional bounds checking.
As it currently stands, this will always be 8 bytes until the ABI changes.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Kees Cook <keescook@chromium.org>
[maz: dropped WARN_ONs]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Kees Cook 2018-06-29 11:46:18 -07:00 committed by Marc Zyngier
parent 1d47191de7
commit 2326aceebc
1 changed files with 10 additions and 4 deletions
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14
virt/kvm/arm/vgic/vgic-its.c
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@ -168,8 +168,14 @@ struct vgic_its_abi {
int (*commit)(struct vgic_its *its);
};
#define ABI_0_ESZ 8
#define ESZ_MAX ABI_0_ESZ
static const struct vgic_its_abi its_table_abi_versions[] = {
[0] = {.cte_esz = 8, .dte_esz = 8, .ite_esz = 8,
[0] = {
.cte_esz = ABI_0_ESZ,
.dte_esz = ABI_0_ESZ,
.ite_esz = ABI_0_ESZ,
.save_tables = vgic_its_save_tables_v0,
.restore_tables = vgic_its_restore_tables_v0,
.commit = vgic_its_commit_v0,
@ -183,7 +189,7 @@ inline const struct vgic_its_abi *vgic_its_get_abi(struct vgic_its *its)
return &its_table_abi_versions[its->abi_rev];
}
int vgic_its_set_abi(struct vgic_its *its, int rev)
static int vgic_its_set_abi(struct vgic_its *its, u32 rev)
{
const struct vgic_its_abi *abi;
@ -1881,14 +1887,14 @@ typedef int (*entry_fn_t)(struct vgic_its *its, u32 id, void *entry,
* Return: < 0 on error, 0 if last element was identified, 1 otherwise
* (the last element may not be found on second level tables)
*/
static int scan_its_table(struct vgic_its *its, gpa_t base, int size, int esz,
static int scan_its_table(struct vgic_its *its, gpa_t base, int size, u32 esz,
int start_id, entry_fn_t fn, void *opaque)
{
struct kvm *kvm = its->dev->kvm;
unsigned long len = size;
int id = start_id;
gpa_t gpa = base;
char entry[esz];
char entry[ESZ_MAX];
int ret;
memset(entry, 0, esz);