On Mon 04 Mar 2024 at 11:22, Li Zetao <[email protected]> wrote:
There is a null-ptr-deref issue reported by kasan:
KASAN: null-ptr-deref in range
[0x0000000000000000-0x0000000000000007]
Call Trace:
<TASK>
bch2_fs_alloc+0x1092/0x2170 [bcachefs]
bch2_fs_open+0x683/0xe10 [bcachefs]
...
When initializing the name of bch_fs, it needs to dynamically
alloc memory
to meet the length of the name. However, when name allocation
failed, it
will cause a null-ptr-deref access exception in subsequent
string copy.
bch2_printbuf_make_room() does return -ENOMEM but
bch2_prt_printf() doesn't check the return code. And there are too
many
callers of bch2_prt_printf() don't check allocation_failure.
Fix this issue by checking if name allocation is successful.
Fixes: 401ec4db6308 ("bcachefs: Printbuf rework")
Signed-off-by: Li Zetao <[email protected]>
---
fs/bcachefs/super.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/bcachefs/super.c b/fs/bcachefs/super.c
index 6b23e11825e6..24fa41bbe7e3 100644
--- a/fs/bcachefs/super.c
+++ b/fs/bcachefs/super.c
@@ -818,13 +818,13 @@ static struct bch_fs *bch2_fs_alloc(struct
bch_sb *sb, struct bch_opts opts)
goto err;
pr_uuid(&name, c->sb.user_uuid.b);
- strscpy(c->name, name.buf, sizeof(c->name));
- printbuf_exit(&name);
-
ret = name.allocation_failure ? -BCH_ERR_ENOMEM_fs_name_alloc
: 0;
if (ret)
goto err;
IIRC, krealloc() doesn't free old pointer if new-size allocation
failed.
There is no printbuf_exit called in label err then memory leak
happens.
--
Su
+ strscpy(c->name, name.buf, sizeof(c->name));
+ printbuf_exit(&name);
+
/* Compat: */
if (le16_to_cpu(sb->version) <=
bcachefs_metadata_version_inode_v2 &&
!BCH_SB_JOURNAL_FLUSH_DELAY(sb))
