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Blame SOURCES/0439-fs-hfsplus-Don-t-fetch-a-key-beyond-the-end-of-the-n.patch

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Daniel Axtens <dja@axtens.net>
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Date: Fri, 22 Jan 2021 18:13:56 +1100
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Subject: [PATCH] fs/hfsplus: Don't fetch a key beyond the end of the node
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Otherwise you get a wild pointer, leading to a bunch of invalid reads.
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Check it falls inside the given node.
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Signed-off-by: Daniel Axtens <dja@axtens.net>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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---
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 grub-core/fs/hfsplus.c | 4 ++++
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 1 file changed, 4 insertions(+)
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diff --git a/grub-core/fs/hfsplus.c b/grub-core/fs/hfsplus.c
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index 03a33ea2477..423f4b956ba 100644
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--- a/grub-core/fs/hfsplus.c
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+++ b/grub-core/fs/hfsplus.c
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@@ -635,6 +635,10 @@ grub_hfsplus_btree_search (struct grub_hfsplus_btree *btree,
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 	      pointer = ((char *) currkey
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 			 + grub_be_to_cpu16 (currkey->keylen)
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 			 + 2);
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+
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+	      if ((char *) pointer > node + btree->nodesize - 2)
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+		return grub_error (GRUB_ERR_BAD_FS, "HFS+ key beyond end of node");
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+
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 	      currnode = grub_be_to_cpu32 (grub_get_unaligned32 (pointer));
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 	      match = 1;
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 	    }