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| author | Christoffer Dall <christoffer.dall@linaro.org> | 2016-08-01 20:25:33 +0200 |
|---|---|---|
| committer | Christoffer Dall <christoffer.dall@linaro.org> | 2016-08-10 11:41:35 +0200 |
| commit | 99e5e886a0a59df267ff6838f763b789847df982 (patch) | |
| tree | a3f144ed79a1cd132ab8c3667a25cedc685e0461 /virt | |
| parent | fd837b08d98c0c9f4f31998f2ed55b9d8694082c (diff) | |
| download | lwn-99e5e886a0a59df267ff6838f763b789847df982.tar.gz lwn-99e5e886a0a59df267ff6838f763b789847df982.zip | |
KVM: arm64: vgic-its: Handle errors from vgic_add_lpi
During low memory conditions, we could be dereferencing a NULL pointer
when vgic_add_lpi fails to allocate memory.
Consider for example this call sequence:
vgic_its_cmd_handle_mapi
itte->irq = vgic_add_lpi(kvm, lpi_nr);
update_lpi_config(kvm, itte->irq, NULL);
ret = kvm_read_guest(kvm, propbase + irq->intid
^^^^
kaboom?
Instead, return an error pointer from vgic_add_lpi and check the return
value from its single caller.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/arm/vgic/vgic-its.c | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index 1bd8adbeae26..d06330abd5e8 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -51,7 +51,7 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid) irq = kzalloc(sizeof(struct vgic_irq), GFP_KERNEL); if (!irq) - return NULL; + return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&irq->lpi_list); INIT_LIST_HEAD(&irq->ap_list); @@ -522,7 +522,8 @@ static void its_free_itte(struct kvm *kvm, struct its_itte *itte) list_del(&itte->itte_list); /* This put matches the get in vgic_add_lpi. */ - vgic_put_irq(kvm, itte->irq); + if (itte->irq) + vgic_put_irq(kvm, itte->irq); kfree(itte); } @@ -713,10 +714,11 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, u32 device_id = its_cmd_get_deviceid(its_cmd); u32 event_id = its_cmd_get_id(its_cmd); u32 coll_id = its_cmd_get_collection(its_cmd); - struct its_itte *itte; + struct its_itte *itte, *new_itte = NULL; struct its_device *device; struct its_collection *collection, *new_coll = NULL; int lpi_nr; + struct vgic_irq *irq; device = find_its_device(its, device_id); if (!device) @@ -747,13 +749,24 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, return -ENOMEM; } + new_itte = itte; itte->event_id = event_id; list_add_tail(&itte->itte_list, &device->itt_head); } itte->collection = collection; itte->lpi = lpi_nr; - itte->irq = vgic_add_lpi(kvm, lpi_nr); + + irq = vgic_add_lpi(kvm, lpi_nr); + if (IS_ERR(irq)) { + if (new_coll) + vgic_its_free_collection(its, coll_id); + if (new_itte) + its_free_itte(kvm, new_itte); + return PTR_ERR(irq); + } + itte->irq = irq; + update_affinity_itte(kvm, itte); /* |