commit 06888d571b51 ("drm/amd/display: Avoid HDCP over-read and corruption")
fixed an overread with an invalid buffer length but added an unnecessary
buffer and copy.
Simplify the code by using a single uint64_t and __builtin_popcountll to
count the number of bits set in the original bksv buffer instead of a loop.
This also avoid a possible unaligned access of the temporary bksv.
Signed-off-by: Joe Perches <[email protected]>
---
It seems quite odd 20 bits set is a magic number here.
Should it be a specific be/le value instead?
drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c
index de872e7958b06..78a4c6dd95d99 100644
--- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c
+++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c
@@ -28,17 +28,10 @@
static inline enum mod_hdcp_status validate_bksv(struct mod_hdcp *hdcp)
{
uint64_t n = 0;
- uint8_t count = 0;
- u8 bksv[sizeof(n)] = { };
- memcpy(bksv, hdcp->auth.msg.hdcp1.bksv, sizeof(hdcp->auth.msg.hdcp1.bksv));
- n = *(uint64_t *)bksv;
+ memcpy(&n, hdcp->auth.msg.hdcp1.bksv, sizeof(hdcp->auth.msg.hdcp1.bksv));
- while (n) {
- count++;
- n &= (n - 1);
- }
- return (count == 20) ? MOD_HDCP_STATUS_SUCCESS :
+ return (__builtin_popcountll(n) == 20) ? MOD_HDCP_STATUS_SUCCESS :
MOD_HDCP_STATUS_HDCP1_INVALID_BKSV;
}
Hi Joe,
I love your patch! Yet something to improve:
[auto build test ERROR on drm-intel/for-linux-next]
[also build test ERROR on drm-exynos/exynos-drm-next linus/master next-20210709]
[cannot apply to kees/for-next/pstore tegra-drm/drm/tegra/for-next drm/drm-next v5.13]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Joe-Perches/drm-amd-display-Simplify-hdcp-validate_bksv/20210712-034708
base: git://anongit.freedesktop.org/drm-intel for-linux-next
config: i386-randconfig-a003-20210712 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
# https://github.com/0day-ci/linux/commit/66fae2c1becdcb71c95f2c6a6413de4dfe1deb51
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Joe-Perches/drm-amd-display-Simplify-hdcp-validate_bksv/20210712-034708
git checkout 66fae2c1becdcb71c95f2c6a6413de4dfe1deb51
# save the attached .config to linux build tree
make W=1 ARCH=i386
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>, old ones prefixed by <<):
>> ERROR: modpost: "__popcountdi2" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] undefined!
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
On Mon, 2021-07-12 at 07:02 +0800, kernel test robot wrote:
> Hi Joe,
>
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on drm-intel/for-linux-next]
> [also build test ERROR on drm-exynos/exynos-drm-next linus/master next-20210709]
> [cannot apply to kees/for-next/pstore tegra-drm/drm/tegra/for-next drm/drm-next v5.13]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url: https://github.com/0day-ci/linux/commits/Joe-Perches/drm-amd-display-Simplify-hdcp-validate_bksv/20210712-034708
> base: git://anongit.freedesktop.org/drm-intel for-linux-next
> config: i386-randconfig-a003-20210712 (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> reproduce (this is a W=1 build):
> ????????# https://github.com/0day-ci/linux/commit/66fae2c1becdcb71c95f2c6a6413de4dfe1deb51
> ????????git remote add linux-review https://github.com/0day-ci/linux
> ????????git fetch --no-tags linux-review Joe-Perches/drm-amd-display-Simplify-hdcp-validate_bksv/20210712-034708
> ????????git checkout 66fae2c1becdcb71c95f2c6a6413de4dfe1deb51
> ????????# save the attached .config to linux build tree
> ????????make W=1 ARCH=i386
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <[email protected]>
>
> All errors (new ones prefixed by >>, old ones prefixed by <<):
>
> > > ERROR: modpost: "__popcountdi2" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] undefined!
curious.
Anyone know why?
Hi Joe,
I love your patch! Yet something to improve:
[auto build test ERROR on drm-intel/for-linux-next]
[also build test ERROR on drm-tip/drm-tip drm-exynos/exynos-drm-next linus/master v5.14-rc1 next-20210709]
[cannot apply to kees/for-next/pstore tegra-drm/drm/tegra/for-next drm/drm-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Joe-Perches/drm-amd-display-Simplify-hdcp-validate_bksv/20210712-034708
base: git://anongit.freedesktop.org/drm-intel for-linux-next
config: arm64-allyesconfig (attached as .config)
compiler: aarch64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/66fae2c1becdcb71c95f2c6a6413de4dfe1deb51
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Joe-Perches/drm-amd-display-Simplify-hdcp-validate_bksv/20210712-034708
git checkout 66fae2c1becdcb71c95f2c6a6413de4dfe1deb51
# save the attached .config to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross O=build_dir ARCH=arm64 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
aarch64-linux-ld: Unexpected GOT/PLT entries detected!
aarch64-linux-ld: Unexpected run-time procedure linkages detected!
aarch64-linux-ld: drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.o: in function `validate_bksv':
>> hdcp1_execution.c:(.text+0x5ac): undefined reference to `__popcountdi2'
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]