47 lines
1.8 KiB
Diff
47 lines
1.8 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Michael Chang <mchang@suse.com>
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Date: Fri, 31 May 2024 15:14:23 +0800
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Subject: [PATCH] fs/ext2: Fix out-of-bounds read for inline extents
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When inline extents are used, i.e. the extent tree depth equals zero,
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a maximum of four entries can fit into the inode's data block. If the
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extent header states a number of entries greater than four the current
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ext2 implementation causes an out-of-bounds read. Fix this issue by
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capping the number of extents to four when reading inline extents.
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Reported-by: Daniel Axtens <dja@axtens.net>
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Signed-off-by: Michael Chang <mchang@suse.com>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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---
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grub-core/fs/ext2.c | 10 +++++++++-
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1 file changed, 9 insertions(+), 1 deletion(-)
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diff --git a/grub-core/fs/ext2.c b/grub-core/fs/ext2.c
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index e1cc5e62a..3f9f6b208 100644
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--- a/grub-core/fs/ext2.c
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+++ b/grub-core/fs/ext2.c
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@@ -495,6 +495,8 @@ grub_ext2_read_block (grub_fshelp_node_t node, grub_disk_addr_t fileblock)
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struct grub_ext4_extent *ext;
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int i;
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grub_disk_addr_t ret;
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+ grub_uint16_t nent;
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+ const grub_uint16_t max_inline_ext = sizeof (inode->blocks) / sizeof (*ext) - 1; /* Minus 1 extent header. */
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if (grub_ext4_find_leaf (data, (struct grub_ext4_extent_header *) inode->blocks.dir_blocks,
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fileblock, &leaf) != GRUB_ERR_NONE)
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@@ -508,7 +510,13 @@ grub_ext2_read_block (grub_fshelp_node_t node, grub_disk_addr_t fileblock)
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return 0;
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ext = (struct grub_ext4_extent *) (leaf + 1);
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- for (i = 0; i < grub_le_to_cpu16 (leaf->entries); i++)
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+
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+ nent = grub_le_to_cpu16 (leaf->entries);
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+
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+ if (leaf->depth == 0)
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+ nent = grub_min (nent, max_inline_ext);
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+
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+ for (i = 0; i < nent; i++)
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{
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if (fileblock < grub_le_to_cpu32 (ext[i].block))
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break;
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