paride/pcd: Fix potential NULL pointer dereference and mem leak

YueHaibing · axboe · commit f0d176255401 · 2019-04-05T09:24:34.000-06:00
Syzkaller report this: pcd: pcd version 1.07, major 46, nice 0 pcd0: Autoprobe failed pcd: No CD-ROM drive found kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP KASAN PTI CPU: 1 PID: 4525 Comm: syz-executor.0 Not tainted 5.1.0-rc3+ torvalds#8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 RIP: 0010:pcd_init+0x95c/0x1000 [pcd] Code: c4 ab f7 48 89 d8 48 c1 e8 03 80 3c 28 00 74 08 48 89 df e8 56 a3 da f7 4c 8b 23 49 8d bc 24 80 05 00 00 48 89 f8 48 c1 e8 03 <80> 3c 28 00 74 05 e8 39 a3 da f7 49 8b bc 24 80 05 00 00 e8 cc b2 RSP: 0018:ffff8881e84df880 EFLAGS: 00010202 RAX: 00000000000000b0 RBX: ffffffffc155a088 RCX: ffffffffc1508935 RDX: 0000000000040000 RSI: ffffc900014f0000 RDI: 0000000000000580 RBP: dffffc0000000000 R08: ffffed103ee658b8 R09: ffffed103ee658b8 R10: 0000000000000001 R11: ffffed103ee658b7 R12: 0000000000000000 R13: ffffffffc155a778 R14: ffffffffc155a4a8 R15: 0000000000000003 FS: 00007fe71bee3700(0000) GS:ffff8881f7300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055a7334441a8 CR3: 00000001e9674003 CR4: 00000000007606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? 0xffffffffc1508000 ? 0xffffffffc1508000 do_one_initcall+0xbc/0x47d init/main.c:901 do_init_module+0x1b5/0x547 kernel/module.c:3456 load_module+0x6405/0x8c10 kernel/module.c:3804 __do_sys_finit_module+0x162/0x190 kernel/module.c:3898 do_syscall_64+0x9f/0x450 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x462e99 Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe71bee2c58 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 RAX: ffffffffffffffda RBX: 000000000073bf00 RCX: 0000000000462e99 RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000003 RBP: 00007fe71bee2c70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe71bee36bc R13: 00000000004bcefa R14: 00000000006f6fb0 R15: 0000000000000004 Modules linked in: pcd(+) paride solos_pci atm ts_fsm rtc_mt6397 mac80211 nhc_mobility nhc_udp nhc_ipv6 nhc_hop nhc_dest nhc_fragment nhc_routing 6lowpan rtc_cros_ec memconsole intel_xhci_usb_role_switch roles rtc_wm8350 usbcore industrialio_triggered_buffer kfifo_buf industrialio asc7621 dm_era dm_persistent_data dm_bufio dm_mod tpm gnss_ubx gnss_serial serdev gnss max2165 cpufreq_dt hid_penmount hid menf21bmc_wdt rc_core n_tracesink ide_gd_mod cdns_csi2tx v4l2_fwnode videodev media pinctrl_lewisburg pinctrl_intel iptable_security iptable_raw iptable_mangle iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_filter bpfilter ip6_vti ip_vti ip_gre ipip sit tunnel4 ip_tunnel hsr veth netdevsim vxcan batman_adv cfg80211 rfkill chnl_net caif nlmon dummy team bonding vcan bridge stp llc ip6_gre gre ip6_tunnel tunnel6 tun joydev mousedev ppdev kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel aes_x86_64 crypto_simd ide_pci_generic piix input_leds cryptd glue_helper psmouse ide_core intel_agp serio_raw intel_gtt ata_generic i2c_piix4 agpgart pata_acpi parport_pc parport floppy rtc_cmos sch_fq_codel ip_tables x_tables sha1_ssse3 sha1_generic ipv6 [last unloaded: bmc150_magn] Dumping ftrace buffer: (ftrace buffer empty) ---[ end trace d873691c3cd69f56 ]--- If alloc_disk fails in pcd_init_units, cd->disk will be NULL, however in pcd_detect and pcd_exit, it's not check this before free.It may result a NULL pointer dereference. Also when register_blkdev failed, blk_cleanup_queue() and blk_mq_free_tag_set() should be called to free resources. Reported-by: Hulk Robot <hulkci@huawei.com> Fixes: 81b74ac ("paride/pcd: cleanup queues when detection fails") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/block/paride/pcd.c b/drivers/block/paride/pcd.c
@@ -314,6 +314,7 @@ static void pcd_init_units(void)
 		disk->queue = blk_mq_init_sq_queue(&cd->tag_set, &pcd_mq_ops,
 						   1, BLK_MQ_F_SHOULD_MERGE);
 		if (IS_ERR(disk->queue)) {
+			put_disk(disk);
 			disk->queue = NULL;
 			continue;
 		}
@@ -750,6 +751,8 @@ static int pcd_detect(void)
 
 	printk("%s: No CD-ROM drive found\n", name);
 	for (unit = 0, cd = pcd; unit < PCD_UNITS; unit++, cd++) {
+		if (!cd->disk)
+			continue;
 		blk_cleanup_queue(cd->disk->queue);
 		cd->disk->queue = NULL;
 		blk_mq_free_tag_set(&cd->tag_set);
@@ -1010,8 +1013,14 @@ static int __init pcd_init(void)
 	pcd_probe_capabilities();
 
 	if (register_blkdev(major, name)) {
-		for (unit = 0, cd = pcd; unit < PCD_UNITS; unit++, cd++)
+		for (unit = 0, cd = pcd; unit < PCD_UNITS; unit++, cd++) {
+			if (!cd->disk)
+				continue;
+
+			blk_cleanup_queue(cd->disk->queue);
+			blk_mq_free_tag_set(&cd->tag_set);
 			put_disk(cd->disk);
+		}
 		return -EBUSY;
 	}
 
@@ -1032,6 +1041,9 @@ static void __exit pcd_exit(void)
 	int unit;
 
 	for (unit = 0, cd = pcd; unit < PCD_UNITS; unit++, cd++) {
+		if (!cd->disk)
+			continue;
+
 		if (cd->present) {
 			del_gendisk(cd->disk);
 			pi_release(cd->pi);
