From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Sudhakar Kuppusamy Date: Wed, 6 Apr 2022 18:03:37 +0530 Subject: [PATCH] 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 Signed-off-by: Daniel Axtens Reviewed-by: Daniel Kiper (cherry picked from commit a3988cb3f0a108dd67ac127a79a4c8479d23334e) (cherry picked from commit 7125978aa7d6068812ef6da0ab38ce521ae7eba1) (cherry picked from commit e488538cbf9fc63796c7047550b0598e1ef95c03) --- 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 1cad2615f3..09dc932420 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;