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- From 8338a8238f08d9f3ae4c2ddfff0603eff80af9e2 Mon Sep 17 00:00:00 2001
- From: Daniel Axtens <dja@axtens.net>
- Date: Fri, 15 Jan 2021 14:06:46 +1100
- Subject: [PATCH] video/readers/jpeg: Don't decode data before start of stream
- When a start of stream marker is encountered, we call grub_jpeg_decode_sos()
- which allocates space for a bitmap.
- When a restart marker is encountered, we call grub_jpeg_decode_data() which
- then fills in that bitmap.
- If we get a restart marker before the start of stream marker, we will
- attempt to write to a bitmap_ptr that hasn't been allocated. Catch this
- and bail out. This fixes an attempt to write to NULL.
- Signed-off-by: Daniel Axtens <dja@axtens.net>
- Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
- Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
- ---
- grub-core/video/readers/jpeg.c | 4 ++++
- 1 file changed, 4 insertions(+)
- diff --git a/grub-core/video/readers/jpeg.c b/grub-core/video/readers/jpeg.c
- index e514812..e31602f 100644
- --- a/grub-core/video/readers/jpeg.c
- +++ b/grub-core/video/readers/jpeg.c
- @@ -646,6 +646,10 @@ grub_jpeg_decode_data (struct grub_jpeg_data *data)
- nr1 = (data->image_height + vb - 1) >> (3 + data->log_vs);
- nc1 = (data->image_width + hb - 1) >> (3 + data->log_hs);
-
- + if (data->bitmap_ptr == NULL)
- + return grub_error(GRUB_ERR_BAD_FILE_TYPE,
- + "jpeg: attempted to decode data before start of stream");
- +
- for (; data->r1 < nr1 && (!data->dri || rst);
- data->r1++, data->bitmap_ptr += (vb * data->image_width - hb * nc1) * 3)
- for (c1 = 0; c1 < nc1 && (!data->dri || rst);
- --
- 2.14.2
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