🇰🇷 한글 설명
Linux 커널의 RDMA/rxe 드라이버에서 발생한 취약점으로, free_rd_atomic_resources() 함수 실행 시 메모리 경계 검사 오류가 발생합니다. 기존 할당된 배열을 해제하기 전에 max_dest_rd_atomic 값을 먼저 업데이트함으로써, 해제 과정에서 할당된 범위를 벗어난 메모리에 쓰기를 시도하는 Slab Out-of-Bounds(OOB) 취약점이 존재합니다.
💡 쉬운 설명
컴퓨터 메모리를 정리하는 과정에서, 정리해야 할 목록의 크기를 실제 크기보다 크게 잘못 설정하여 엉뚱한 메모리 영역을 건드리는 오류입니다. 이로 인해 시스템이 충돌하거나 보안 문제가 발생할 수 있습니다.
🇺🇸 원문 (English)
In the Linux kernel, the following vulnerability has been resolved:
RDMA/rxe: Fix OOB in free_rd_atomic_resources()
free_rd_atomic_resources() iterates using qp->attr.max_dest_rd_atomic.
Updating max_dest_rd_atomic before freeing the old array can make the
free path walk past the old allocation and trigger a slab out-of-bounds
write catched by KASAN:
==================================================================
BUG: KASAN: slab-out-of-bounds in free_rd_atomic_resource drivers/infiniband/sw/rxe/rxe_qp.c:180 [inline]
BUG: KASAN: slab-out-of-bounds in free_rd_atomic_resources drivers/infiniband/sw/rxe/rxe_qp.c:171 [inline]
BUG: KASAN: slab-out-of-bounds in free_rd_atomic_resources drivers/infiniband/sw/rxe/rxe_qp.c:163 [inline]
BUG: KASAN: slab-out-of-bounds in rxe_qp_from_attr+0x1e88/0x2150 drivers/infiniband/sw/rxe/rxe_qp.c:712
Write of size 4 at addr ffff88802b8dddb8 by task syz.3.451/11063
CPU: 0 UID: 0 PID: 11063 Comm: syz.3.451 Not tainted 7.1.0 #2 PREEMPT(full)
Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x10e/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xf7/0x600 mm/kasan/report.c:482
kasan_report+0xe4/0x120 mm/kasan/report.c:595
free_rd_atomic_resource drivers/infiniband/sw/rxe/rxe_qp.c:180 [inline]
free_rd_atomic_resources drivers/infiniband/sw/rxe/rxe_qp.c:171 [inline]
free_rd_atomic_resources drivers/infiniband/sw/rxe/rxe_qp.c:163 [inline]
rxe_qp_from_attr+0x1e88/0x2150 drivers/infiniband/sw/rxe/rxe_qp.c:712
rxe_modify_qp+0x1e2/0x530 drivers/infiniband/sw/rxe/rxe_verbs.c:623
ib_security_modify_qp+0x223/0xfa0 drivers/infiniband/core/security.c:625
_ib_modify_qp+0x333/0xec0 drivers/infiniband/core/verbs.c:1915
modify_qp+0x13ca/0x1940 drivers/infiniband/core/uverbs_cmd.c:1932
ib_uverbs_modify_qp+0xcb/0x120 drivers/infiniband/core/uverbs_cmd.c:1958
ib_uverbs_write+0xb86/0x1030 drivers/infiniband/core/uverbs_main.c:680
vfs_write+0x2aa/0x1070 fs/read_write.c:686
ksys_write+0x1f8/0x250 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x116/0x800 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fefc75a70cd
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fefc8495018 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fefc7835fa0 RCX: 00007fefc75a70cd
RDX: 0000000000000078 RSI: 0000200000000240 RDI: 0000000000000007
RBP: 00007fefc764f10f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fefc7836038 R14: 00007fefc7835fa0 R15: 00007ffcf0586aa0
</TASK>
Allocated by task 11063:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5296 [inline]
__kmalloc_noprof+0x32a/0x850 mm/slub.c:5308
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
alloc_rd_atomic_resources drivers/infiniband/sw/rxe/rxe_qp.c:155 [inline]
rxe_qp_from_attr+0x3f8/0x2150 drivers/infiniband/sw/rxe/rxe_qp.c:714
rxe_modify_qp+0x1e2/0x530 drivers/infiniband/sw/rxe/rxe_verbs.c:623
ib_security_modify_qp+0x223/0xfa0 drivers/infiniband/core/security.c:625
_ib_modify_qp+0x333/0xec0 drivers/infiniband/core/verbs.c:1915
modify_qp+0x13ca/0x1940 drivers/infiniband/core/uverbs_cmd.c:1932
ib_uverbs_modify_qp+0xcb/0x120 drivers/infiniband/core/uverbs_cmd.c:1958
ib_uverbs_write+0xb86/0x1030 drivers/infiniband/core/uverbs_ma
---truncated---
📍 영향받는 시스템
Linux kernel (RDMA/rxe driver 사용 환경, 특히 7.1.0 버전 근처)
⚔️ 공격 벡터
RDMA/rxe를 사용하는 환경에서 QP(Queue Pair) 속성을 조작하여 메모리 해제 로직을 트리거함
🛡️ 대응 방법
Linux 커널을 최신 보안 패치가 적용된 버전으로 업데이트하십시오.
🔧 검증 코드
현재 실행 중인 커널 버전을 확인하여 취약점이 해결된 패치 버전인지 확인합니다.