CVE: CVE-2024-47688
Published: 2024-10-21
Description: In the Linux kernel, the following vulnerability has been resolved:

driver core: Fix a potential null-ptr-deref in module_add_driver()

Inject fault while probing of-fpga-region, if kasprintf() fails in
module_add_driver(), the second sysfs_remove_link() in exit path will cause
null-ptr-deref as below because kernfs_name_hash() will call strlen() with
NULL driver_name.

Fix it by releasing resources based on the exit path sequence.

	 KASAN: null-ptr-deref in range [0x[PII_REDACTED]000000-0x[PII_REDACTED]000007]
	 Mem abort info:
	   ESR = 0x[PII_REDACTED]000005
	   EC = 0x25: DABT (current EL), IL = 32 bits
	   SET = 0, FnV = 0
	   EA = 0, S1PTW = 0
	   FSC = 0x05: level 1 translation fault
	 Data abort info:
	   ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
	   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
	   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
	 [dfffffc000000000] address between user and kernel address ranges
	 Internal error: Oops: [PII_REDACTED] [#1] PREEMPT SMP
	 Dumping ftrace buffer:
	    (ftrace buffer empty)
	 Modules linked in: of_fpga_region(+) fpga_region fpga_bridge cfg80211 rfkill 8021q garp mrp stp llc ipv6 [last unloaded: of_fpga_region]
	 CPU: 2 UID: 0 PID: 2036 Comm: modprobe Not tainted 6.11.0-rc2-g6a0e38264012 #295
	 Hardware name: linux,dummy-virt (DT)
	 pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
	 pc : strlen+0x24/0xb0
	 lr : kernfs_name_hash+0x1c/0xc4
	 sp : ffffffc081f97380
	 x29: ffffffc081f97380 x28: ffffffc081f97b90 x27: ffffff80c821c2a0
	 x26: ffffffedac0be418 x25: [PII_REDACTED] x24: ffffff80c09d2000
	 x23: [PII_REDACTED] x22: [PII_REDACTED] x21: [PII_REDACTED]
	 x20: [PII_REDACTED] x19: [PII_REDACTED] x18: [PII_REDACTED]
	 x17: [PII_REDACTED] x16: [PII_REDACTED] x15: 1ffffff8103f2e42
	 x14: 00000000f1f1f1f1 x13: [PII_REDACTED] x12: ffffffb01812d61d
	 x11: 1ffffff01812d61c x10: ffffffb01812d61c x9 : dfffffc000000000
	 x8 : 0000004fe7ed29e4 x7 : ffffff80c096b0e7 x6 : [PII_REDACTED]
	 x5 : ffffff80c096b0e0 x4 : 1ffffffdb990efa2 x3 : [PII_REDACTED]
	 x2 : [PII_REDACTED] x1 : dfffffc000000000 x0 : [PII_REDACTED]
	 Call trace:
	  strlen+0x24/0xb0
	  kernfs_name_hash+0x1c/0xc4
	  kernfs_find_ns+0x118/0x2e8
	  kernfs_remove_by_name_ns+0x80/0x100
	  sysfs_remove_link+0x74/0xa8
	  module_add_driver+0x278/0x394
	  bus_add_driver+0x1f0/0x43c
	  driver_register+0xf4/0x3c0
	  __platform_driver_register+0x60/0x88
	  of_fpga_region_init+0x20/0x1000 [of_fpga_region]
	  do_one_initcall+0x110/0x788
	  do_init_module+0x1dc/0x5c8
	  load_module+0x3c38/0x4cac
	  init_module_from_file+0xd4/0x128
	  idempotent_init_module+0x2cc/0x528
	  __arm64_sys_finit_module+0xac/0x100
	  invoke_syscall+0x6c/0x258
	  el0_svc_common.constprop.0+0x160/0x22c
	  do_el0_svc+0x44/0x5c
	  el0_svc+0x48/0xb8
	  el0t_64_sync_handler+0x13c/0x158
	  el0t_64_sync+0x190/0x194
	 Code: f2fbffe1 a90157f4 12000802 aa0003f5 (38e16861)
	 ---[ end trace [PII_REDACTED] ]---
	 Kernel panic - not syncing: Oops: Fatal exception
CVSS Score: 5.5 (MEDIUM)
CWE: CWE-476
References: https://git.kernel.org/stable/c/18ec12c97b39ff6aa15beb8d2b25d15cd44b87d8; https://git.kernel.org/stable/c/4b5d48b7a29cc6d508121a4b4e0c97a891e5273c; https://git.kernel.org/stable/c/b8e45b[PII_REDACTED]10d10c9dcbf2abf3005aa97c