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Message-Id: <20210104155707.006708825@linuxfoundation.org>
Date: Mon, 4 Jan 2021 16:57:25 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Rustam Kovhaev <rkovhaev@...il.com>,
Jan Kara <jack@...e.cz>,
syzbot+83b6f7cf9922cae5c4d7@...kaller.appspotmail.com
Subject: [PATCH 5.4 26/47] reiserfs: add check for an invalid ih_entry_count
From: Rustam Kovhaev <rkovhaev@...il.com>
commit d24396c5290ba8ab04ba505176874c4e04a2d53c upstream.
when directory item has an invalid value set for ih_entry_count it might
trigger use-after-free or out-of-bounds read in bin_search_in_dir_item()
ih_entry_count * IH_SIZE for directory item should not be larger than
ih_item_len
Link: https://lore.kernel.org/r/20201101140958.3650143-1-rkovhaev@gmail.com
Reported-and-tested-by: syzbot+83b6f7cf9922cae5c4d7@...kaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=83b6f7cf9922cae5c4d7
Signed-off-by: Rustam Kovhaev <rkovhaev@...il.com>
Signed-off-by: Jan Kara <jack@...e.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
fs/reiserfs/stree.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/fs/reiserfs/stree.c
+++ b/fs/reiserfs/stree.c
@@ -454,6 +454,12 @@ static int is_leaf(char *buf, int blocks
"(second one): %h", ih);
return 0;
}
+ if (is_direntry_le_ih(ih) && (ih_item_len(ih) < (ih_entry_count(ih) * IH_SIZE))) {
+ reiserfs_warning(NULL, "reiserfs-5093",
+ "item entry count seems wrong %h",
+ ih);
+ return 0;
+ }
prev_location = ih_location(ih);
}
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