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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Trek <trek00@inbox.ru>,
        Alex Deucher <alexander.deucher@amd.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 36/61] drm/amdgpu: Check for valid number of registers to read
Date:   Thu, 10 Oct 2019 10:37:01 +0200
Message-Id: <20191010083512.929771258@linuxfoundation.org>
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From: Trek <trek00@inbox.ru>

[ Upstream commit 73d8e6c7b841d9bf298c8928f228fb433676635c ]

Do not try to allocate any amount of memory requested by the user.
Instead limit it to 128 registers. Actually the longest series of
consecutive allowed registers are 48, mmGB_TILE_MODE0-31 and
mmGB_MACROTILE_MODE0-15 (0x2644-0x2673).

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=111273
Signed-off-by: Trek <trek00@inbox.ru>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index e16229000a983..884ed359f2493 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -540,6 +540,9 @@ static int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file
 		if (sh_num == AMDGPU_INFO_MMR_SH_INDEX_MASK)
 			sh_num = 0xffffffff;
 
+		if (info->read_mmr_reg.count > 128)
+			return -EINVAL;
+
 		regs = kmalloc_array(info->read_mmr_reg.count, sizeof(*regs), GFP_KERNEL);
 		if (!regs)
 			return -ENOMEM;
-- 
2.20.1