From: Alex Deucher <alexdeucher@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: "Alex Deucher" <alexander.deucher@amd.com>,
"Martin Tsai" <martin.tsai@amd.com>,
"Leo Li" <sunpeng.li@amd.com>,
LKML <linux-kernel@vger.kernel.org>,
"Wenjing Liu" <wenjing.liu@amd.com>,
"Anson Jacob" <Anson.Jacob@amd.com>,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
"Nicholas Kazlauskas" <nicholas.kazlauskas@amd.com>,
"David Airlie" <airlied@linux.ie>,
"Daniel Wheeler" <daniel.wheeler@amd.com>,
"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
"Christian König" <christian.koenig@amd.com>,
"Bindu Ramamurthy" <bindu.r@amd.com>
Subject: Re: [PATCH] drm/amd/display: Avoid HDCP over-read and corruption
Date: Tue, 1 Jun 2021 22:06:11 -0400 [thread overview]
Message-ID: <CADnq5_PsvOqBW4-WDvR7BqaZgq3R8vYRPz2=c+87Dokk-zWz_A@mail.gmail.com> (raw)
In-Reply-To: <20210528175354.790719-1-keescook@chromium.org>
On Fri, May 28, 2021 at 1:54 PM Kees Cook <keescook@chromium.org> wrote:
>
> Instead of reading the desired 5 bytes of the actual target field,
> the code was reading 8. This could result in a corrupted value if the
> trailing 3 bytes were non-zero, so instead use an appropriately sized
> and zero-initialized bounce buffer, and read only 5 bytes before casting
> to u64.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
Applied. Thanks!
> ---
> drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> 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 2cbd931363bd..6d26d9c63ab2 100644
> --- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c
> +++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c
> @@ -29,8 +29,10 @@ 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(&n, hdcp->auth.msg.hdcp1.bksv, sizeof(uint64_t));
> + memcpy(bksv, hdcp->auth.msg.hdcp1.bksv, sizeof(hdcp->auth.msg.hdcp1.bksv));
> + n = *(uint64_t *)bksv;
>
> while (n) {
> count++;
> --
> 2.25.1
>
WARNING: multiple messages have this Message-ID (diff)
From: Alex Deucher <alexdeucher@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: "Martin Tsai" <martin.tsai@amd.com>,
"Leo Li" <sunpeng.li@amd.com>, "David Airlie" <airlied@linux.ie>,
"Wenjing Liu" <wenjing.liu@amd.com>,
LKML <linux-kernel@vger.kernel.org>,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
"Christian König" <christian.koenig@amd.com>,
"Anson Jacob" <Anson.Jacob@amd.com>,
"Daniel Wheeler" <daniel.wheeler@amd.com>,
"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Nicholas Kazlauskas" <nicholas.kazlauskas@amd.com>,
"Bindu Ramamurthy" <bindu.r@amd.com>
Subject: Re: [PATCH] drm/amd/display: Avoid HDCP over-read and corruption
Date: Tue, 1 Jun 2021 22:06:11 -0400 [thread overview]
Message-ID: <CADnq5_PsvOqBW4-WDvR7BqaZgq3R8vYRPz2=c+87Dokk-zWz_A@mail.gmail.com> (raw)
In-Reply-To: <20210528175354.790719-1-keescook@chromium.org>
On Fri, May 28, 2021 at 1:54 PM Kees Cook <keescook@chromium.org> wrote:
>
> Instead of reading the desired 5 bytes of the actual target field,
> the code was reading 8. This could result in a corrupted value if the
> trailing 3 bytes were non-zero, so instead use an appropriately sized
> and zero-initialized bounce buffer, and read only 5 bytes before casting
> to u64.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
Applied. Thanks!
> ---
> drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> 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 2cbd931363bd..6d26d9c63ab2 100644
> --- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c
> +++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c
> @@ -29,8 +29,10 @@ 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(&n, hdcp->auth.msg.hdcp1.bksv, sizeof(uint64_t));
> + memcpy(bksv, hdcp->auth.msg.hdcp1.bksv, sizeof(hdcp->auth.msg.hdcp1.bksv));
> + n = *(uint64_t *)bksv;
>
> while (n) {
> count++;
> --
> 2.25.1
>
WARNING: multiple messages have this Message-ID (diff)
From: Alex Deucher <alexdeucher@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: "Martin Tsai" <martin.tsai@amd.com>,
"Leo Li" <sunpeng.li@amd.com>, "David Airlie" <airlied@linux.ie>,
"Wenjing Liu" <wenjing.liu@amd.com>,
LKML <linux-kernel@vger.kernel.org>,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
"Christian König" <christian.koenig@amd.com>,
"Anson Jacob" <Anson.Jacob@amd.com>,
"Daniel Wheeler" <daniel.wheeler@amd.com>,
"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Nicholas Kazlauskas" <nicholas.kazlauskas@amd.com>,
"Bindu Ramamurthy" <bindu.r@amd.com>
Subject: Re: [PATCH] drm/amd/display: Avoid HDCP over-read and corruption
Date: Tue, 1 Jun 2021 22:06:11 -0400 [thread overview]
Message-ID: <CADnq5_PsvOqBW4-WDvR7BqaZgq3R8vYRPz2=c+87Dokk-zWz_A@mail.gmail.com> (raw)
In-Reply-To: <20210528175354.790719-1-keescook@chromium.org>
On Fri, May 28, 2021 at 1:54 PM Kees Cook <keescook@chromium.org> wrote:
>
> Instead of reading the desired 5 bytes of the actual target field,
> the code was reading 8. This could result in a corrupted value if the
> trailing 3 bytes were non-zero, so instead use an appropriately sized
> and zero-initialized bounce buffer, and read only 5 bytes before casting
> to u64.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
Applied. Thanks!
> ---
> drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> 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 2cbd931363bd..6d26d9c63ab2 100644
> --- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c
> +++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp1_execution.c
> @@ -29,8 +29,10 @@ 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(&n, hdcp->auth.msg.hdcp1.bksv, sizeof(uint64_t));
> + memcpy(bksv, hdcp->auth.msg.hdcp1.bksv, sizeof(hdcp->auth.msg.hdcp1.bksv));
> + n = *(uint64_t *)bksv;
>
> while (n) {
> count++;
> --
> 2.25.1
>
_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
next prev parent reply other threads:[~2021-06-02 2:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-28 17:53 [PATCH] drm/amd/display: Avoid HDCP over-read and corruption Kees Cook
2021-05-28 17:53 ` Kees Cook
2021-05-28 17:53 ` Kees Cook
2021-06-02 2:06 ` Alex Deucher [this message]
2021-06-02 2:06 ` Alex Deucher
2021-06-02 2:06 ` Alex Deucher
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