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From 2d014248d540c7e087934a94b6e7a2aa7fc2c704 Mon Sep 17 00:00:00 2001
From: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Date: Wed, 6 Apr 2022 18:03:37 +0530
Subject: fs/f2fs: Do not read past the end of nat journal entries
A corrupt f2fs file system could specify a nat journal entry count
that is beyond the maximum NAT_JOURNAL_ENTRIES.
Check if the specified nat journal entry count before accessing the
array, and throw an error if it is too large.
Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/fs/f2fs.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/grub-core/fs/f2fs.c b/grub-core/fs/f2fs.c
index 8a9992ca9..63702214b 100644
--- a/grub-core/fs/f2fs.c
+++ b/grub-core/fs/f2fs.c
@@ -632,23 +632,27 @@ get_nat_journal (struct grub_f2fs_data *data)
return err;
}
-static grub_uint32_t
-get_blkaddr_from_nat_journal (struct grub_f2fs_data *data, grub_uint32_t nid)
+static grub_err_t
+get_blkaddr_from_nat_journal (struct grub_f2fs_data *data, grub_uint32_t nid,
+ grub_uint32_t *blkaddr)
{
grub_uint16_t n = grub_le_to_cpu16 (data->nat_j.n_nats);
- grub_uint32_t blkaddr = 0;
grub_uint16_t i;
+ if (n > NAT_JOURNAL_ENTRIES)
+ return grub_error (GRUB_ERR_BAD_FS,
+ "invalid number of nat journal entries");
+
for (i = 0; i < n; i++)
{
if (grub_le_to_cpu32 (data->nat_j.entries[i].nid) == nid)
{
- blkaddr = grub_le_to_cpu32 (data->nat_j.entries[i].ne.block_addr);
+ *blkaddr = grub_le_to_cpu32 (data->nat_j.entries[i].ne.block_addr);
break;
}
}
- return blkaddr;
+ return GRUB_ERR_NONE;
}
static grub_uint32_t
@@ -656,10 +660,13 @@ get_node_blkaddr (struct grub_f2fs_data *data, grub_uint32_t nid)
{
struct grub_f2fs_nat_block *nat_block;
grub_uint32_t seg_off, block_off, entry_off, block_addr;
- grub_uint32_t blkaddr;
+ grub_uint32_t blkaddr = 0;
grub_err_t err;
- blkaddr = get_blkaddr_from_nat_journal (data, nid);
+ err = get_blkaddr_from_nat_journal (data, nid, &blkaddr);
+ if (err != GRUB_ERR_NONE)
+ return 0;
+
if (blkaddr)
return blkaddr;
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