From 88361a7fd4e481a76e1159a63c9014fa997ef29c Mon Sep 17 00:00:00 2001 From: Darren Kenny Date: Fri, 4 Dec 2020 15:39:00 +0000 Subject: [PATCH] video/readers/jpeg: Test for an invalid next marker reference from a jpeg file While it may never happen, and potentially could be caught at the end of the function, it is worth checking up front for a bad reference to the next marker just in case of a maliciously crafted file being provided. Fixes: CID 73694 Signed-off-by: Darren Kenny Reviewed-by: Daniel Kiper Upstream-Status: Backport [https://git.savannah.gnu.org/cgit/grub.git/commit/?id=5f5eb7ca8e971227e95745abe541df3e1509360e] Signed-off-by: Marta Rybczynska --- grub-core/video/readers/jpeg.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/grub-core/video/readers/jpeg.c b/grub-core/video/readers/jpeg.c index 31359a4..0b6ce3c 100644 --- a/grub-core/video/readers/jpeg.c +++ b/grub-core/video/readers/jpeg.c @@ -253,6 +253,12 @@ grub_jpeg_decode_quan_table (struct grub_jpeg_data *data) next_marker = data->file->offset; next_marker += grub_jpeg_get_word (data); + if (next_marker > data->file->size) + { + /* Should never be set beyond the size of the file. */ + return grub_error (GRUB_ERR_BAD_FILE_TYPE, "jpeg: invalid next reference"); + } + while (data->file->offset + sizeof (data->quan_table[id]) + 1 <= next_marker) {