31 lines
1.2 KiB
Diff
31 lines
1.2 KiB
Diff
From 18c6c043bd7d8f139f30e9c7749013115d5fc5b7 Mon Sep 17 00:00:00 2001
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From: Valentin Lefebvre <valentin.lefebvre@suse.com>
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Date: Wed, 20 Sep 2023 12:04:56 +0200
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Subject: [PATCH] mmappend.c: Avoid invalid access for header entry
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* zzip_disk_entry_to_file_header checking the pointer by substraction
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instead of addition where it could lead to an invalid access memory.
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* CVE-2020-18770
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Signed-off-by: Valentin Lefebvre <valentin.lefebvre@suse.com>
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---
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zzip/mmapped.c | 5 +++--
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1 file changed, 3 insertions(+), 2 deletions(-)
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diff --git a/zzip/mmapped.c b/zzip/mmapped.c
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index 2071882..beb094d 100644
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--- a/zzip/mmapped.c
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+++ b/zzip/mmapped.c
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@@ -275,8 +275,9 @@ zzip_disk_entry_to_data(ZZIP_DISK * disk, struct zzip_disk_entry * entry)
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struct zzip_file_header *
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zzip_disk_entry_to_file_header(ZZIP_DISK * disk, struct zzip_disk_entry *entry)
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{
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- zzip_byte_t *const ptr = disk->buffer + zzip_disk_entry_fileoffset(entry);
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- if (disk->buffer > ptr || ptr >= disk->endbuf)
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+ zzip_off_t off = zzip_disk_entry_fileoffset(entry);
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+ zzip_byte_t *const ptr = disk->buffer + off;
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+ if (disk->buffer > ptr || disk->buffer >= disk->endbuf - off)
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{
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errno = EBADMSG;
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return 0;
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