* [PATCH] drm/i915/gvt: Fix use-after-free in intel_vgpu_create_workload
@ 2019-08-07 2:20 Gustavo A. R. Silva
0 siblings, 0 replies; only message in thread
From: Gustavo A. R. Silva @ 2019-08-07 2:20 UTC (permalink / raw)
To: Zhenyu Wang, Zhi Wang, Jani Nikula, Joonas Lahtinen,
Rodrigo Vivi, David Airlie, Daniel Vetter, Xiong Zhang
Cc: intel-gvt-dev, intel-gfx, dri-devel, linux-kernel, Gustavo A. R. Silva
kmem_cache_free() frees *workload*, hence there is a use-after-free bug
when calling function gvt_vgpu_err().
Fix this by storing the value of workload->wa_ctx.indirect_ctx.guest_gma
and workload->wa_ctx.per_ctx.guest_gma into automatic variable
guest_gma before freeing *workload*, for its further use.
Addresses-Coverity-ID: 1452235 ("Read from pointer after free")
Fixes: 2089a76ade90 ("drm/i915/gvt: Checking workload's gma earlier")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/gpu/drm/i915/gvt/scheduler.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index 32ae6b5b7e16..c8cdb4a309f6 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -1525,9 +1525,11 @@ intel_vgpu_create_workload(struct intel_vgpu *vgpu, int ring_id,
if (!intel_gvt_ggtt_validate_range(vgpu,
workload->wa_ctx.indirect_ctx.guest_gma,
workload->wa_ctx.indirect_ctx.size)) {
+ unsigned long guest_gma =
+ workload->wa_ctx.indirect_ctx.guest_gma;
kmem_cache_free(s->workloads, workload);
gvt_vgpu_err("invalid wa_ctx at: 0x%lx\n",
- workload->wa_ctx.indirect_ctx.guest_gma);
+ guest_gma);
return ERR_PTR(-EINVAL);
}
}
@@ -1539,9 +1541,11 @@ intel_vgpu_create_workload(struct intel_vgpu *vgpu, int ring_id,
if (!intel_gvt_ggtt_validate_range(vgpu,
workload->wa_ctx.per_ctx.guest_gma,
CACHELINE_BYTES)) {
+ unsigned long guest_gma =
+ workload->wa_ctx.per_ctx.guest_gma;
kmem_cache_free(s->workloads, workload);
gvt_vgpu_err("invalid per_ctx at: 0x%lx\n",
- workload->wa_ctx.per_ctx.guest_gma);
+ guest_gma);
return ERR_PTR(-EINVAL);
}
}
--
2.22.0
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