linux-f2fs-devel.lists.sourceforge.net archive mirror
 help / color / mirror / Atom feed
* [f2fs-dev] [PATCH] f2fs: fix to do sanity check on .cp_pack_total_block_count
@ 2022-03-21 15:22 Chao Yu
  0 siblings, 0 replies; only message in thread
From: Chao Yu @ 2022-03-21 15:22 UTC (permalink / raw)
  To: jaegeuk; +Cc: linux-kernel, stable, linux-f2fs-devel

As bughunter reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=215709

f2fs may hang when mounting a fuzzed image, the dmesg shows as below:

__filemap_get_folio+0x3a9/0x590
pagecache_get_page+0x18/0x60
__get_meta_page+0x95/0x460 [f2fs]
get_checkpoint_version+0x2a/0x1e0 [f2fs]
validate_checkpoint+0x8e/0x2a0 [f2fs]
f2fs_get_valid_checkpoint+0xd0/0x620 [f2fs]
f2fs_fill_super+0xc01/0x1d40 [f2fs]
mount_bdev+0x18a/0x1c0
f2fs_mount+0x15/0x20 [f2fs]
legacy_get_tree+0x28/0x50
vfs_get_tree+0x27/0xc0
path_mount+0x480/0xaa0
do_mount+0x7c/0xa0
__x64_sys_mount+0x8b/0xe0
do_syscall_64+0x38/0xc0
entry_SYSCALL_64_after_hwframe+0x44/0xae

The root cause is cp_pack_total_block_count field in checkpoint was fuzzed
to one, as calcuated, two cp pack block locates in the same block address,
so then read latter cp pack block, it will block on the page lock due to
the lock has already held when reading previous cp pack block, fix it by
adding sanity check for cp_pack_total_block_count.

Cc: stable@vger.kernel.org
Signed-off-by: Chao Yu <chao.yu@oppo.com>
---
 fs/f2fs/checkpoint.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 871eee35a32f..aba1b8a1ce66 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -875,6 +875,7 @@ static struct page *validate_checkpoint(struct f2fs_sb_info *sbi,
 	struct page *cp_page_1 = NULL, *cp_page_2 = NULL;
 	struct f2fs_checkpoint *cp_block = NULL;
 	unsigned long long cur_version = 0, pre_version = 0;
+	unsigned int cp_blocks;
 	int err;
 
 	err = get_checkpoint_version(sbi, cp_addr, &cp_block,
@@ -882,15 +883,16 @@ static struct page *validate_checkpoint(struct f2fs_sb_info *sbi,
 	if (err)
 		return NULL;
 
-	if (le32_to_cpu(cp_block->cp_pack_total_block_count) >
-					sbi->blocks_per_seg) {
+	cp_blocks = le32_to_cpu(cp_block->cp_pack_total_block_count);
+
+	if (cp_blocks > sbi->blocks_per_seg || cp_blocks <= F2FS_CP_PACKS) {
 		f2fs_warn(sbi, "invalid cp_pack_total_block_count:%u",
 			  le32_to_cpu(cp_block->cp_pack_total_block_count));
 		goto invalid_cp;
 	}
 	pre_version = *version;
 
-	cp_addr += le32_to_cpu(cp_block->cp_pack_total_block_count) - 1;
+	cp_addr += cp_blocks - 1;
 	err = get_checkpoint_version(sbi, cp_addr, &cp_block,
 					&cp_page_2, version);
 	if (err)
-- 
2.25.1



_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

^ permalink raw reply	[flat|nested] only message in thread

only message in thread, other threads:[~2022-03-21 15:22 UTC | newest]

Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-21 15:22 [f2fs-dev] [PATCH] f2fs: fix to do sanity check on .cp_pack_total_block_count Chao Yu

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).