51 lines
1.8 KiB
Diff
51 lines
1.8 KiB
Diff
From e896e9dde50fd9a44cbbed205cc0beb869e2193b Mon Sep 17 00:00:00 2001
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From: Kees Cook <keescook@chromium.org>
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Date: Mon, 11 Mar 2013 17:31:45 -0700
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Subject: [PATCH] drm/i915: bounds check execbuffer relocation count
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It is possible to wrap the counter used to allocate the buffer for
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relocation copies. This could lead to heap writing overflows.
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CVE-2013-0913
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v3: collapse test, improve comment
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v2: move check into validate_exec_list
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Signed-off-by: Kees Cook <keescook@chromium.org>
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Reported-by: Pinkie Pie
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Cc: stable@vger.kernel.org
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---
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drivers/gpu/drm/i915/i915_gem_execbuffer.c | 11 ++++++++---
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1 file changed, 8 insertions(+), 3 deletions(-)
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diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
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index 26d08bb..7adf5a7 100644
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--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
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+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
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@@ -706,15 +706,20 @@ validate_exec_list(struct drm_i915_gem_exec_object2 *exec,
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int count)
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{
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int i;
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+ int relocs_total = 0;
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+ int relocs_max = INT_MAX / sizeof(struct drm_i915_gem_relocation_entry);
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for (i = 0; i < count; i++) {
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char __user *ptr = (char __user *)(uintptr_t)exec[i].relocs_ptr;
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int length; /* limited by fault_in_pages_readable() */
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- /* First check for malicious input causing overflow */
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- if (exec[i].relocation_count >
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- INT_MAX / sizeof(struct drm_i915_gem_relocation_entry))
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+ /* First check for malicious input causing overflow in
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+ * the worst case where we need to allocate the entire
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+ * relocation tree as a single array.
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+ */
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+ if (exec[i].relocation_count > relocs_max - relocs_total)
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return -EINVAL;
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+ relocs_total += exec[i].relocation_count;
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length = exec[i].relocation_count *
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sizeof(struct drm_i915_gem_relocation_entry);
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--
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1.8.1.2
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