CVE-2019-11810 (published 2019-05-07T14:29Z)

An issue was discovered in the Linux kernel before 5.0.7. A NULL pointer dereference can occur when megasas_create_frame_pool() fails in megasas_alloc_cmds() in drivers/scsi/megaraid/megaraid_sas_base.c. This causes a Denial of Service, related to a use-after-free.

Severity: HIGH
CVSS v2 base score: 7.8 (AV:N/AC:L/Au:N/C:N/I:N/A:C)
CVSS v3 base score: 7.5, HIGH (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Weakness information:
cwe_id: CWE-476
cwe_name: NULL Pointer Dereference
description: The product dereferences a pointer that it expects to be valid but is NULL.
extended_description: 
            
            
            
         
         
cwe_id: CWE-416
cwe_name: Use After Free
description: The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
extended_description: 
             
             
             
			 
             
             
         
         

Fix information:
repo_url: https://github.com/torvalds/linux
commit_details: repo_url: https://github.com/torvalds/linux
author: Jason Yan
author_date: 2019-02-15 19:50:27+08:00
msg: scsi: megaraid_sas: return error when create DMA pool failed

when create DMA pool for cmd frames failed, we should return -ENOMEM,
instead of 0.
In some case in:

    megasas_init_adapter_fusion()

    -->megasas_alloc_cmds()
       -->megasas_create_frame_pool
          create DMA pool failed,
        --> megasas_free_cmds() [1]

    -->megasas_alloc_cmds_fusion()
       failed, then goto fail_alloc_cmds.
    -->megasas_free_cmds() [2]

we will call megasas_free_cmds twice, [1] will kfree cmd_list,
[2] will use cmd_list.it will cause a problem:

Unable to handle kernel NULL pointer dereference at virtual address
00000000
pgd = ffffffc000f70000
[00000000] *pgd=0000001fbf893003, *pud=0000001fbf893003,
*pmd=0000001fbf894003, *pte=006000006d000707
Internal error: Oops: 96000005 [#1] SMP
 Modules linked in:
 CPU: 18 PID: 1 Comm: swapper/0 Not tainted
 task: ffffffdfb9290000 ti: ffffffdfb923c000 task.ti: ffffffdfb923c000
 PC is at megasas_free_cmds+0x30/0x70
 LR is at megasas_free_cmds+0x24/0x70
 ...
 Call trace:
 [<ffffffc0005b779c>] megasas_free_cmds+0x30/0x70
 [<ffffffc0005bca74>] megasas_init_adapter_fusion+0x2f4/0x4d8
 [<ffffffc0005b926c>] megasas_init_fw+0x2dc/0x760
 [<ffffffc0005b9ab0>] megasas_probe_one+0x3c0/0xcd8
 [<ffffffc0004a5abc>] local_pci_probe+0x4c/0xb4
 [<ffffffc0004a5c40>] pci_device_probe+0x11c/0x14c
 [<ffffffc00053a5e4>] driver_probe_device+0x1ec/0x430
 [<ffffffc00053a92c>] __driver_attach+0xa8/0xb0
 [<ffffffc000538178>] bus_for_each_dev+0x74/0xc8
  [<ffffffc000539e88>] driver_attach+0x28/0x34
 [<ffffffc000539a18>] bus_add_driver+0x16c/0x248
 [<ffffffc00053b234>] driver_register+0x6c/0x138
 [<ffffffc0004a5350>] __pci_register_driver+0x5c/0x6c
 [<ffffffc000ce3868>] megasas_init+0xc0/0x1a8
 [<ffffffc000082a58>] do_one_initcall+0xe8/0x1ec
 [<ffffffc000ca7be8>] kernel_init_freeable+0x1c8/0x284
 [<ffffffc0008d90b8>] kernel_init+0x1c/0xe4

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Acked-by: Sumit Saxena <sumit.saxena@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
repository: repo_url: https://github.com/torvalds/linux
repo_name: torvalds/linux
description: Linux kernel source tree
repo_language: C
owner: torvalds
file_changes: filename: megaraid_sas_base.c
change_type: ModificationType.MODIFY
diff: @@ -4188,6 +4188,7 @@ int megasas_alloc_cmds(struct megasas_instance *instance)
 	if (megasas_create_frame_pool(instance)) {
 		dev_printk(KERN_DEBUG, &instance->pdev->dev, "Error creating frame DMA pool\n");
 		megasas_free_cmds(instance);
+		return -ENOMEM;
 	}
 
 	return 0;

programming_language: C