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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2018-05-22 00:05:30 +0300 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2018-05-22 12:47:07 +0300 |
| commit | 84b510e22da7926522a257cfe295d3695346a0bd (patch) | |
| tree | 2727b27a6fe7db45f7d973f340d09d42d52ed305 /drivers/gpu/drm/i915/i915_query.c | |
| parent | d93fa1b47b8fcd149b5091f18385304f402a8e15 (diff) | |
| download | linux-84b510e22da7926522a257cfe295d3695346a0bd.tar.xz | |
drm/i915/query: Protect tainted function pointer lookup
Smatch identifies i915_query_ioctl() as being a potential victim of
Spectre due to its use of a tainted user index into a function pointer
array. Use array_index_nospec() to defang the user index before using it
to lookup the function pointer.
Fixes: a446ae2c6e65 ("drm/i915: add query uAPI")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180521210530.26008-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/i915_query.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_query.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c index 3ace929dd90f..95f9d179afc4 100644 --- a/drivers/gpu/drm/i915/i915_query.c +++ b/drivers/gpu/drm/i915/i915_query.c @@ -4,6 +4,8 @@ * Copyright © 2018 Intel Corporation */ +#include <linux/nospec.h> + #include "i915_drv.h" #include "i915_query.h" #include <uapi/drm/i915_drm.h> @@ -111,10 +113,12 @@ int i915_query_ioctl(struct drm_device *dev, void *data, struct drm_file *file) func_idx = item.query_id - 1; - if (func_idx < ARRAY_SIZE(i915_query_funcs)) + ret = -EINVAL; + if (func_idx < ARRAY_SIZE(i915_query_funcs)) { + func_idx = array_index_nospec(func_idx, + ARRAY_SIZE(i915_query_funcs)); ret = i915_query_funcs[func_idx](dev_priv, &item); - else - ret = -EINVAL; + } /* Only write the length back to userspace if they differ. */ if (ret != item.length && put_user(ret, &user_item_ptr->length)) |