[PATCH AUTOSEL 5.18 34/39] f2fs: fix to do sanity check on segment type in build_sit_entries()

Sasha Levin
2022-08-14T16:33:44Z

From: Chao Yu <chao.yu@oppo.com>

[ Upstream commit 09beadf289d6e300553e60d6e76f13c0427ecab3 ]

As Wenqing Liu <wenqingliu0120@gmail.com> reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=216285

RIP: 0010:memcpy_erms+0x6/0x10
f2fs_update_meta_page+0x84/0x570 [f2fs]
change_curseg.constprop.0+0x159/0xbd0 [f2fs]
f2fs_do_replace_block+0x5c7/0x18a0 [f2fs]
f2fs_replace_block+0xeb/0x180 [f2fs]
recover_data+0x1abd/0x6f50 [f2fs]
f2fs_recover_fsync_data+0x12ce/0x3250 [f2fs]
f2fs_fill_super+0x4459/0x6190 [f2fs]
mount_bdev+0x2cf/0x3b0
legacy_get_tree+0xed/0x1d0
vfs_get_tree+0x81/0x2b0
path_mount+0x47e/0x19d0
do_mount+0xce/0xf0
__x64_sys_mount+0x12c/0x1a0
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The root cause is segment type is invalid, so in f2fs_do_replace_block(),
f2fs accesses f2fs_sm_info::curseg_array with out-of-range segment type,
result in accessing invalid curseg->sum_blk during memcpy in
f2fs_update_meta_page(). Fix this by adding sanity check on segment type
in build_sit_entries().

Reported-by: Wenqing Liu <wenqingliu0120@gmail.com>
Signed-off-by: Chao Yu <chao.yu@oppo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/segment.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index aa0162664a1e..15c72bfca692 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -4486,6 +4486,12 @@ static int build_sit_entries(struct f2fs_sb_info *sbi)
return err;
seg_info_from_raw_sit(se, &sit);

+ if (se->type >= NR_PERSISTENT_LOG) {
+ f2fs_err(sbi, "Invalid segment type: %u, segno: %u",
+ se->type, start);
+ return -EFSCORRUPTED;
+ }
+
sit_valid_blocks[SE_PAGETYPE(se)] += se->valid_blocks;

if (f2fs_block_unit_discard(sbi)) {
@@ -4534,6 +4540,13 @@ static int build_sit_entries(struct f2fs_sb_info *sbi)
break;
seg_info_from_raw_sit(se, &sit);

+ if (se->type >= NR_PERSISTENT_LOG) {
+ f2fs_err(sbi, "Invalid segment type: %u, segno: %u",
+ se->type, start);
+ err = -EFSCORRUPTED;
+ break;
+ }
+
sit_valid_blocks[SE_PAGETYPE(se)] += se->valid_blocks;

if (f2fs_block_unit_discard(sbi)) {
--
2.35.1