The ploop_add_delta() function calls file_clone_open() to create multiple file handles, but only checks for NULL return values. However, file_clone_open() can return ERR_PTR() on failure, which gets stored as a corrupted file pointer in deltas[level].mtfile[i].
Later, during cleanup in ploop_put_delta(), fput() is called on these corrupted pointers , causing the kernel to attempt accessing invalid memory addresses resulting in NULL pointer dereference crashes. BUG: kernel NULL pointer dereference, address: 0000000000000034 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP PTI CPU: 6 PID: 274635 Comm: dmsetup ve: / Kdump: loaded Tainted: G X ------- --- 5.14.0-427.77.1.vz9.86.12 #1 86.12 Hardware name: Supermicro SYS-5039MS-H12NR/X11SSE-F, BIOS 2.3 12/12/2019 RIP: 0010:fput_many+0x7/0x90 RSP: 0018:ffffa55e45ab3bd0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000001 RDI: fffffffffffffffc RBP: ffff8aaf304a2800 R08: ffff8aaebbc83800 R09: 20c49ba5e353f7cf R10: ffff8aaec85428f0 R11: ffffffffc05c41fc R12: ffff8aaf287d9f40 R13: ffff8aaf28692000 R14: 0000000000000004 R15: 0000000000000003 FS: 00007feb47a0d840(0000) GS:ffff8abc77b80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000034 CR3: 0000000323e94003 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? show_trace_log_lvl+0x1c4/0x2df ? show_trace_log_lvl+0x1c4/0x2df ? ploop_put_delta+0x51/0x76 [ploop] ? __die_body.cold+0x8/0xd ? page_fault_oops+0x134/0x170 ? exc_page_fault+0x62/0x150 ? asm_exc_page_fault+0x22/0x30 ? fuse_generic_request_alloc+0x1c/0x80 [fuse] ? fput_many+0x7/0x90 ploop_put_delta+0x51/0x76 [ploop] ploop_destroy+0x17b/0x2a0 [ploop] dm_table_destroy+0x59/0x120 [dm_mod] dev_remove+0xdb/0x1a0 [dm_mod] ctl_ioctl+0x1a5/0x290 [dm_mod] dm_ctl_ioctl+0xa/0x20 [dm_mod] __x64_sys_ioctl+0x87/0xc0 do_syscall_64+0x59/0x90 ? syscall_exit_work+0x103/0x130 ? syscall_exit_to_user_mode+0x19/0x40 ? do_syscall_64+0x69/0x90 ? exit_to_user_mode_loop+0xd0/0x130 ? exit_to_user_mode_prepare+0xb6/0x100 ? syscall_exit_to_user_mode+0x19/0x40 ? do_syscall_64+0x69/0x90 ? do_user_addr_fault+0x1d6/0x6a0 ? syscall_exit_work+0x103/0x130 ? exc_page_fault+0x62/0x150 entry_SYSCALL_64_after_hwframe+0x77/0xe1 RIP: 0033:0x7feb4783ec6b RSP: 002b:00007ffdc8dc7c98 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007feb47c0fbd0 RCX: 00007feb4783ec6b RDX: 00005651f9b00c80 RSI: 00000000c138fd04 RDI: 0000000000000003 RBP: 00007feb47c4c316 R08: 00007feb47c4f2d8 R09: 00007ffdc8dc7af0 R10: 00007feb47c4c316 R11: 0000000000000206 R12: 00005651f9b00c80 R13: 00005651f9b00d30 R14: 00007feb47c4c316 R15: 00005651f9b00a00 </TASK> CR2: 0000000000000034 Fix by: 1. Using IS_ERR() to properly detect error pointers from file_clone_open() 2. Adding IS_ERR() checks in ploop_put_delta() to prevent cleanup crashes 3. Setting failed mtfile entries to NULL to avoid double-free issues https://virtuozzo.atlassian.net/browse/VSTOR-116965 Signed-off-by: Vasileios Almpanis <[email protected]> Feature: dm-ploop: ploop target driver --- drivers/md/dm-ploop-bat.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-ploop-bat.c b/drivers/md/dm-ploop-bat.c index a0b678b30b97..65c74960f29c 100644 --- a/drivers/md/dm-ploop-bat.c +++ b/drivers/md/dm-ploop-bat.c @@ -511,8 +511,9 @@ int ploop_add_delta(struct ploop *ploop, u32 level, struct file *file, bool is_r } for (i = 0; i < ploop->nkt_runners; i++) { deltas[level].mtfile[i] = file_clone_open(file); - if (!deltas[level].mtfile[i]) { - ret = ENOMEM; + if (IS_ERR(deltas[level].mtfile[i])) { + ret = PTR_ERR(deltas[level].mtfile[i]); + deltas[level].mtfile[i] = NULL; goto out; } } @@ -531,14 +532,14 @@ void ploop_put_delta(struct ploop *ploop, struct ploop_delta *delta) { int i; - if (delta->file) { + if (delta->file && !IS_ERR(delta->file)) { vfs_fsync(delta->file, 1); fput(delta->file); } if (delta->mtfile) { for (i = 0; i < ploop->nkt_runners; i++) { - if (delta->mtfile[i]) + if (delta->mtfile[i] && !IS_ERR(delta->mtfile[i])) fput(delta->mtfile[i]); } kfree(delta->mtfile); -- 2.43.0 _______________________________________________ Devel mailing list [email protected] https://lists.openvz.org/mailman/listinfo/devel
