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Message-ID: <48d9f9b4-8b28-f24b-c0bd-d899c59bd247@gmail.com>
Date: Thu, 17 Oct 2024 12:34:28 +0200
From: Jacek Anaszewski <jacek.anaszewski@...il.com>
To: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Cc: Andrzej Pietrasiewicz <andrzejtp2010@...il.com>,
Hans Verkuil <hans.verkuil@...co.com>,
Sylwester Nawrocki <s.nawrocki@...sung.com>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-media@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH 07/13] media: s5p-jpeg: prevent buffer overflows
Hi Mauro,
On 10/16/24 12:22, Mauro Carvalho Chehab wrote:
> The current logic allows word to be less than 2. If this happens,
> there will be buffer overflows. Add extra checks to prevent it.
>
> While here, remove an unused word = 0 assignment.
>
> Fixes: 6c96dbbc2aa9 ("[media] s5p-jpeg: add support for 5433")
> Cc: stable@...r.kernel.org
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> ---
> .../media/platform/samsung/s5p-jpeg/jpeg-core.c | 17 +++++++++++------
> 1 file changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/media/platform/samsung/s5p-jpeg/jpeg-core.c b/drivers/media/platform/samsung/s5p-jpeg/jpeg-core.c
> index d2c4a0178b3c..1db4609b3557 100644
> --- a/drivers/media/platform/samsung/s5p-jpeg/jpeg-core.c
> +++ b/drivers/media/platform/samsung/s5p-jpeg/jpeg-core.c
> @@ -775,11 +775,14 @@ static void exynos4_jpeg_parse_decode_h_tbl(struct s5p_jpeg_ctx *ctx)
> (unsigned long)vb2_plane_vaddr(&vb->vb2_buf, 0) + ctx->out_q.sos + 2;
> jpeg_buffer.curr = 0;
>
> - word = 0;
> -
> if (get_word_be(&jpeg_buffer, &word))
> return;
> - jpeg_buffer.size = (long)word - 2;
> +
> + if (word < 2)
> + jpeg_buffer.size = 0;
> + else
> + jpeg_buffer.size = (long)word - 2;
> +
> jpeg_buffer.data += 2;
> jpeg_buffer.curr = 0;
>
> @@ -1058,6 +1061,7 @@ static int get_word_be(struct s5p_jpeg_buffer *buf, unsigned int *word)
> if (byte == -1)
> return -1;
> *word = (unsigned int)byte | temp;
> +
> return 0;
> }
>
> @@ -1145,7 +1149,7 @@ static bool s5p_jpeg_parse_hdr(struct s5p_jpeg_q_data *result,
> if (get_word_be(&jpeg_buffer, &word))
> break;
> length = (long)word - 2;
> - if (!length)
> + if (length <= 0)
> return false;
> sof = jpeg_buffer.curr; /* after 0xffc0 */
> sof_len = length;
> @@ -1176,7 +1180,7 @@ static bool s5p_jpeg_parse_hdr(struct s5p_jpeg_q_data *result,
> if (get_word_be(&jpeg_buffer, &word))
> break;
> length = (long)word - 2;
> - if (!length)
> + if (length <= 0)
> return false;
> if (n_dqt >= S5P_JPEG_MAX_MARKER)
> return false;
> @@ -1189,7 +1193,7 @@ static bool s5p_jpeg_parse_hdr(struct s5p_jpeg_q_data *result,
> if (get_word_be(&jpeg_buffer, &word))
> break;
> length = (long)word - 2;
> - if (!length)
> + if (length <= 0)
> return false;
> if (n_dht >= S5P_JPEG_MAX_MARKER)
> return false;
> @@ -1214,6 +1218,7 @@ static bool s5p_jpeg_parse_hdr(struct s5p_jpeg_q_data *result,
> if (get_word_be(&jpeg_buffer, &word))
> break;
> length = (long)word - 2;
> + /* No need to check underflows as skip() does it */
> skip(&jpeg_buffer, length);
> break;
> }
Seems reasonable.
Reviewed-by: Jacek Anaszewski <jacek.anaszewski@...il.com>
--
Best regards,
Jacek Anaszewski
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