Commit 2326acee authored by Kees Cook's avatar Kees Cook Committed by Marc Zyngier
Browse files

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: default avatarKees Cook <keescook@chromium.org>
[maz: dropped WARN_ONs]
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 1d47191d

virt/kvm/arm/vgic/vgic-its.c

+10 −4
Original line number Diff line number Diff line
@@ -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);

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