drm/i915/gem: Replace user_access_begin by user_write_access_begin (b44f6873) · Commits · 戴 / test

When i915_gem_execbuffer2_ioctl() is using user_access_begin(), that's only to perform unsafe_put_user() so use user_write_access_begin() in order to only open write access. Signed-off-by:

Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by:

Kees Cook <keescook@chromium.org> Signed-off-by:

Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/ebf1250b6d4f351469fb339e5399d8b92aa8a1c1.1585898438.git.christophe.leroy@c-s.fr

drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -2794,7 +2794,8 @@ i915_gem_execbuffer2_ioctl(struct drm_device dev, void data,
		* And this range already got effectively checked earlier
		* when we did the "copy_from_user()" above.
		*/
		if (!user_access_begin(user_exec_list, count * sizeof(*user_exec_list)))
		if (!user_write_access_begin(user_exec_list,
		count * sizeof(*user_exec_list)))
		goto end;

		for (i = 0; i < args->buffer_count; i++) {
		@@ -2808,7 +2809,7 @@ i915_gem_execbuffer2_ioctl(struct drm_device dev, void data,
		end_user);
		}
		end_user:
		user_access_end();
		user_write_access_end();
		end:;
		}

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