From: Ye Bin <yebin10@huawei.com> hulk inclusion category: bugfix bugzilla: 185945, https://gitee.com/openeuler/kernel/issues/I4O33F CVE: NA ----------------------------------------------- We got issue as follows when run syzkaller test: [ 1901.130043] EXT4-fs error (device vda): ext4_remount:5624: comm syz-executor.5: Abort forced by user [ 1901.130901] Aborting journal on device vda-8. [ 1901.131437] EXT4-fs error (device vda): ext4_journal_check_start:61: comm syz-executor.16: Detected aborted journal [ 1901.131566] EXT4-fs error (device vda): ext4_journal_check_start:61: comm syz-executor.11: Detected aborted journal [ 1901.132586] EXT4-fs error (device vda): ext4_journal_check_start:61: comm syz-executor.18: Detected aborted journal [ 1901.132751] EXT4-fs error (device vda): ext4_journal_check_start:61: comm syz-executor.9: Detected aborted journal [ 1901.136149] EXT4-fs error (device vda) in ext4_reserve_inode_write:6035: Journal has aborted [ 1901.136837] EXT4-fs error (device vda): ext4_journal_check_start:61: comm syz-fuzzer: Detected aborted journal [ 1901.136915] ================================================================== [ 1901.138175] BUG: KASAN: null-ptr-deref in __ext4_journal_ensure_credits+0x74/0x140 [ext4] [ 1901.138343] EXT4-fs error (device vda): ext4_journal_check_start:61: comm syz-executor.13: Detected aborted journal [ 1901.138398] EXT4-fs error (device vda): ext4_journal_check_start:61: comm syz-executor.1: Detected aborted journal [ 1901.138808] Read of size 8 at addr 0000000000000000 by task syz-executor.17/968 [ 1901.138817] [ 1901.138852] EXT4-fs error (device vda): ext4_journal_check_start:61: comm syz-executor.30: Detected aborted journal [ 1901.144779] CPU: 1 PID: 968 Comm: syz-executor.17 Not tainted 4.19.90-vhulk2111.1.0.h893.eulerosv2r10.aarch64+ #1 [ 1901.146479] Hardware name: linux,dummy-virt (DT) [ 1901.147317] Call trace: [ 1901.147552] dump_backtrace+0x0/0x2d8 [ 1901.147898] show_stack+0x28/0x38 [ 1901.148215] dump_stack+0xec/0x15c [ 1901.148746] kasan_report+0x108/0x338 [ 1901.149207] __asan_load8+0x58/0xb0 [ 1901.149753] __ext4_journal_ensure_credits+0x74/0x140 [ext4] [ 1901.150579] ext4_xattr_delete_inode+0xe4/0x700 [ext4] [ 1901.151316] ext4_evict_inode+0x524/0xba8 [ext4] [ 1901.151985] evict+0x1a4/0x378 [ 1901.152353] iput+0x310/0x428 [ 1901.152733] do_unlinkat+0x260/0x428 [ 1901.153056] __arm64_sys_unlinkat+0x6c/0xc0 [ 1901.153455] el0_svc_common+0xc8/0x320 [ 1901.153799] el0_svc_handler+0xf8/0x160 [ 1901.154265] el0_svc+0x10/0x218 [ 1901.154682] ================================================================== This issue may happens like this: Process1 Process2 ext4_evict_inode ext4_journal_start ext4_truncate ext4_ind_truncate ext4_free_branches ext4_ind_truncate_ensure_credits ext4_journal_ensure_credits_fn ext4_journal_restart handle->h_transaction = NULL; mount -o remount,abort /mnt -> trigger JBD abort start_this_handle -> will return failed ext4_xattr_delete_inode ext4_journal_ensure_credits ext4_journal_ensure_credits_fn __ext4_journal_ensure_credits jbd2_handle_buffer_credits journal = handle->h_transaction->t_journal; ->null-ptr-deref Now, indirect truncate process didn't handle error. To solve this issue maybe simply add check handle is abort in '__ext4_journal_ensure_credits' is enough, and i also think this is necessary. Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- fs/ext4/ext4_jbd2.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index 022ab8afd9499..2c6dc99292fdc 100644 --- a/fs/ext4/ext4_jbd2.c +++ b/fs/ext4/ext4_jbd2.c @@ -140,6 +140,8 @@ int __ext4_journal_ensure_credits(handle_t *handle, int check_cred, { if (!ext4_handle_valid(handle)) return 0; + if (is_handle_aborted(handle)) + return -EROFS; if (jbd2_handle_buffer_credits(handle) >= check_cred && handle->h_revoke_credits >= revoke_cred) return 0; -- 2.25.1