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	This fixes CVE-2022-1304: An out-of-bounds read/write vulnerability was found in e2fsprogs 1.46.5. This issue leads to a segmentation fault and possibly arbitrary code execution via a specially crafted filesystem. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
		
			
				
	
	
		
			51 lines
		
	
	
		
			1.7 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			51 lines
		
	
	
		
			1.7 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
From ab51d587bb9b229b1fade1afd02e1574c1ba5c76 Mon Sep 17 00:00:00 2001
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From: Lukas Czerner <lczerner@redhat.com>
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Date: Thu, 21 Apr 2022 19:31:48 +0200
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Subject: libext2fs: add sanity check to extent manipulation
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It is possible to have a corrupted extent tree in such a way that a leaf
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node contains zero extents in it. Currently if that happens and we try
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to traverse the tree we can end up accessing wrong data, or possibly
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even uninitialized memory. Make sure we don't do that.
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Additionally make sure that we have a sane number of bytes passed to
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memmove() in ext2fs_extent_delete().
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Note that e2fsck is currently unable to spot and fix such corruption in
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pass1.
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Signed-off-by: Lukas Czerner <lczerner@redhat.com>
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Reported-by: Nils Bars <nils_bars@t-online.de>
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Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=2068113
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Addresses: CVE-2022-1304
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Addresses-Debian-Bug: #1010263
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Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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---
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 lib/ext2fs/extent.c | 8 ++++++++
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 1 file changed, 8 insertions(+)
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--- a/lib/ext2fs/extent.c
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+++ b/lib/ext2fs/extent.c
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@@ -495,6 +495,10 @@ retry:
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 			ext2fs_le16_to_cpu(eh->eh_entries);
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 		newpath->max_entries = ext2fs_le16_to_cpu(eh->eh_max);
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+		/* Make sure there is at least one extent present */
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+		if (newpath->left <= 0)
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+			return EXT2_ET_EXTENT_NO_DOWN;
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+
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 		if (path->left > 0) {
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 			ix++;
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 			newpath->end_blk = ext2fs_le32_to_cpu(ix->ei_block);
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@@ -1630,6 +1634,10 @@ errcode_t ext2fs_extent_delete(ext2_exte
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 	cp = path->curr;
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+	/* Sanity check before memmove() */
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+	if (path->left < 0)
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+		return EXT2_ET_EXTENT_LEAF_BAD;
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+
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 	if (path->left) {
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 		memmove(cp, cp + sizeof(struct ext3_extent_idx),
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 			path->left * sizeof(struct ext3_extent_idx));
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