samsung_sm8750/android_kernel_samsung_sm8750
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

f2fs: fix to do sanity check on sit_bitmap_size

Browse Source 
commit 5db0d252c64e91ba1929c70112352e85dc5751e7 upstream.

w/ below testcase, resize will generate a corrupted image which
contains inconsistent metadata, so when mounting such image, it
will trigger kernel panic:

touch img
truncate -s $((512*1024*1024*1024)) img
mkfs.f2fs -f img $((256*1024*1024))
resize.f2fs -s -i img -t $((1024*1024*1024))
mount img /mnt/f2fs

------------[ cut here ]------------
kernel BUG at fs/f2fs/segment.h:863!
Oops: invalid opcode: 0000 [#1] SMP PTI
CPU: 11 UID: 0 PID: 3922 Comm: mount Not tainted 6.15.0-rc1+ #191 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:f2fs_ra_meta_pages+0x47c/0x490

Call Trace:
 f2fs_build_segment_manager+0x11c3/0x2600
 f2fs_fill_super+0xe97/0x2840
 mount_bdev+0xf4/0x140
 legacy_get_tree+0x2b/0x50
 vfs_get_tree+0x29/0xd0
 path_mount+0x487/0xaf0
 __x64_sys_mount+0x116/0x150
 do_syscall_64+0x82/0x190
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fdbfde1bcfe

The reaseon is:

sit_i->bitmap_size is 192, so size of sit bitmap is 192*8=1536, at maximum
there are 1536 sit blocks, however MAIN_SEGS is 261893, so that sit_blk_cnt
is 4762, build_sit_entries() -> current_sit_addr() tries to access
out-of-boundary in sit_bitmap at offset from [1536, 4762), once sit_bitmap
and sit_bitmap_mirror is not the same, it will trigger f2fs_bug_on().

Let's add sanity check in f2fs_sanity_check_ckpt() to avoid panic.

Cc: stable@vger.kernel.org
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Chao Yu
2025-04-14 18:55:20 +08:00
committed by Greg Kroah-Hartman
parent a87cbcc909
commit 79ef8a6c4e
1 changed files with 8 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
fs/f2fs/super.c
View File

@@ -3608,6 +3608,7 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi)
block_t user_block_count, valid_user_blocks; block_t user_block_count, valid_user_blocks;
block_t avail_node_count, valid_node_count; block_t avail_node_count, valid_node_count;
unsigned int nat_blocks, nat_bits_bytes, nat_bits_blocks; unsigned int nat_blocks, nat_bits_bytes, nat_bits_blocks;
unsigned int sit_blk_cnt;
int i, j; int i, j;
total = le32_to_cpu(raw_super->segment_count); total = le32_to_cpu(raw_super->segment_count);
@@ -3719,6 +3720,13 @@ skip_cross:
return 1; return 1;
} }
sit_blk_cnt = DIV_ROUND_UP(main_segs, SIT_ENTRY_PER_BLOCK);
if (sit_bitmap_size * 8 < sit_blk_cnt) {
f2fs_err(sbi, "Wrong bitmap size: sit: %u, sit_blk_cnt:%u",
sit_bitmap_size, sit_blk_cnt);
return 1;
}
cp_pack_start_sum = __start_sum_addr(sbi); cp_pack_start_sum = __start_sum_addr(sbi);
cp_payload = __cp_payload(sbi); cp_payload = __cp_payload(sbi);
if (cp_pack_start_sum < cp_payload + 1 || if (cp_pack_start_sum < cp_payload + 1 ||