From: Ye Bin <yebin10@xxxxxxxxxx> [ Upstream commit f650ef61e040bcb175dd8762164b00a5d627f20e ] BUG: KASAN: use-after-free in ata_scsi_mode_select_xlat+0x10bd/0x10f0 drivers/ata/libata-scsi.c:4045 Read of size 1 at addr ffff88803b8cd003 by task syz-executor.6/12621 CPU: 1 PID: 12621 Comm: syz-executor.6 Not tainted 4.19.95 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xac/0xee lib/dump_stack.c:118 print_address_description+0x60/0x223 mm/kasan/report.c:253 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xae/0x2d8 mm/kasan/report.c:393 ata_scsi_mode_select_xlat+0x10bd/0x10f0 drivers/ata/libata-scsi.c:4045 ata_scsi_translate+0x2da/0x680 drivers/ata/libata-scsi.c:2035 __ata_scsi_queuecmd drivers/ata/libata-scsi.c:4360 [inline] ata_scsi_queuecmd+0x2e4/0x790 drivers/ata/libata-scsi.c:4409 scsi_dispatch_cmd+0x2ee/0x6c0 drivers/scsi/scsi_lib.c:1867 scsi_queue_rq+0xfd7/0x1990 drivers/scsi/scsi_lib.c:2170 blk_mq_dispatch_rq_list+0x1e1/0x19a0 block/blk-mq.c:1186 blk_mq_do_dispatch_sched+0x147/0x3d0 block/blk-mq-sched.c:108 blk_mq_sched_dispatch_requests+0x427/0x680 block/blk-mq-sched.c:204 __blk_mq_run_hw_queue+0xbc/0x200 block/blk-mq.c:1308 __blk_mq_delay_run_hw_queue+0x3c0/0x460 block/blk-mq.c:1376 blk_mq_run_hw_queue+0x152/0x310 block/blk-mq.c:1413 blk_mq_sched_insert_request+0x337/0x6c0 block/blk-mq-sched.c:397 blk_execute_rq_nowait+0x124/0x320 block/blk-exec.c:64 blk_execute_rq+0xc5/0x112 block/blk-exec.c:101 sg_scsi_ioctl+0x3b0/0x6a0 block/scsi_ioctl.c:507 sg_ioctl+0xd37/0x23f0 drivers/scsi/sg.c:1106 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0xae6/0x1030 fs/ioctl.c:688 ksys_ioctl+0x76/0xa0 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710 do_syscall_64+0xa0/0x2e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c479 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb0e9602c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fb0e96036d4 RCX: 000000000045c479 RDX: 0000000020000040 RSI: 0000000000000001 RDI: 0000000000000003 RBP: 000000000076bfc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000046d R14: 00000000004c6e1a R15: 000000000076bfcc Allocated by task 12577: set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc mm/kasan/kasan.c:553 [inline] kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:531 __kmalloc+0xf3/0x1e0 mm/slub.c:3749 kmalloc include/linux/slab.h:520 [inline] load_elf_phdrs+0x118/0x1b0 fs/binfmt_elf.c:441 load_elf_binary+0x2de/0x4610 fs/binfmt_elf.c:737 search_binary_handler fs/exec.c:1654 [inline] search_binary_handler+0x15c/0x4e0 fs/exec.c:1632 exec_binprm fs/exec.c:1696 [inline] __do_execve_file.isra.0+0xf52/0x1a90 fs/exec.c:1820 do_execveat_common fs/exec.c:1866 [inline] do_execve fs/exec.c:1883 [inline] __do_sys_execve fs/exec.c:1964 [inline] __se_sys_execve fs/exec.c:1959 [inline] __x64_sys_execve+0x8a/0xb0 fs/exec.c:1959 do_syscall_64+0xa0/0x2e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 12577: set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x129/0x170 mm/kasan/kasan.c:521 slab_free_hook mm/slub.c:1370 [inline] slab_free_freelist_hook mm/slub.c:1397 [inline] slab_free mm/slub.c:2952 [inline] kfree+0x8b/0x1a0 mm/slub.c:3904 load_elf_binary+0x1be7/0x4610 fs/binfmt_elf.c:1118 search_binary_handler fs/exec.c:1654 [inline] search_binary_handler+0x15c/0x4e0 fs/exec.c:1632 exec_binprm fs/exec.c:1696 [inline] __do_execve_file.isra.0+0xf52/0x1a90 fs/exec.c:1820 do_execveat_common fs/exec.c:1866 [inline] do_execve fs/exec.c:1883 [inline] __do_sys_execve fs/exec.c:1964 [inline] __se_sys_execve fs/exec.c:1959 [inline] __x64_sys_execve+0x8a/0xb0 fs/exec.c:1959 do_syscall_64+0xa0/0x2e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88803b8ccf00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 259 bytes inside of 512-byte region [ffff88803b8ccf00, ffff88803b8cd100) The buggy address belongs to the page: page:ffffea0000ee3300 count:1 mapcount:0 mapping:ffff88806cc03080 index:0xffff88803b8cc780 compound_mapcount: 0 flags: 0x100000000008100(slab|head) raw: 0100000000008100 ffffea0001104080 0000000200000002 ffff88806cc03080 raw: ffff88803b8cc780 00000000800c000b 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88803b8ccf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803b8ccf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88803b8cd000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803b8cd080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803b8cd100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc You can refer to "https://www.lkml.org/lkml/2019/1/17/474"; reproduce this error. The exception code is "bd_len = p[3];", "p" value is ffff88803b8cd000 which belongs to the cache kmalloc-512 of size 512. The "page_address(sg_page(scsi_sglist(scmd)))" maybe from sg_scsi_ioctl function "buffer" which allocated by kzalloc, so "buffer" may not page aligned. This also looks completely buggy on highmem systems and really needs to use a kmap_atomic. --Christoph Hellwig To address above bugs, Paolo Bonzini advise to simpler to just make a char array of size CACHE_MPAGE_LEN+8+8+4-2(or just 64 to make it easy), use sg_copy_to_buffer to copy from the sglist into the buffer, and workthere. Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/ata/libata-scsi.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 36e588d88b956..c10deb87015ba 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -3692,12 +3692,13 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc) { struct scsi_cmnd *scmd = qc->scsicmd; const u8 *cdb = scmd->cmnd; - const u8 *p; u8 pg, spg; unsigned six_byte, pg_len, hdr_len, bd_len; int len; u16 fp = (u16)-1; u8 bp = 0xff; + u8 buffer[64]; + const u8 *p = buffer; VPRINTK("ENTER\n"); @@ -3731,12 +3732,14 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc) if (!scsi_sg_count(scmd) || scsi_sglist(scmd)->length < len) goto invalid_param_len; - p = page_address(sg_page(scsi_sglist(scmd))); - /* Move past header and block descriptors. */ if (len < hdr_len) goto invalid_param_len; + if (!sg_copy_to_buffer(scsi_sglist(scmd), scsi_sg_count(scmd), + buffer, sizeof(buffer))) + goto invalid_param_len; + if (six_byte) bd_len = p[3]; else -- 2.25.1
