Re: [PATCH 7.1.y] RDMA/rxe: Fix OOB in free_rd_atomic_resources()

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2026/8/31 4:32, Greg KH 写道:
> On Tue, Aug 25, 2026 at 08:17:27PM +0200, Zhu Yanjun wrote:
>> From: Peiyang He <peiyang_he@smail.nju.edu.cn>
>>
>> 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_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
>>
>> The buggy address belongs to the object at ffff88802b8ddd80
>>   which belongs to the cache kmalloc-64 of size 64
>> The buggy address is located 0 bytes to the right of
>>   allocated 56-byte region [ffff88802b8ddd80, ffff88802b8dddb8)
>>
>> The buggy address belongs to the physical page:
>> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b8dd
>> flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
>> page_type: f5(slab)
>> raw: 00fff00000000000 ffff888015c418c0 dead000000000100 dead000000000122
>> raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000
>> page dumped because: kasan: bad access detected
>> page_owner tracks the page as allocated
>> page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4651, tgid 4651 ((udev-worker)), ts 123427165316, free_ts 123425874255
>>   set_page_owner include/linux/page_owner.h:32 [inline]
>>   post_alloc_hook+0xfc/0x120 mm/page_alloc.c:1853
>>   prep_new_page mm/page_alloc.c:1861 [inline]
>>   get_page_from_freelist+0x75b/0x3220 mm/page_alloc.c:3941
>>   __alloc_frozen_pages_noprof+0x27e/0x2b00 mm/page_alloc.c:5221
>>   alloc_slab_page mm/slub.c:3278 [inline]
>>   allocate_slab mm/slub.c:3467 [inline]
>>   new_slab+0xa6/0x670 mm/slub.c:3525
>>   refill_objects+0x278/0x420 mm/slub.c:7272
>>   refill_sheaf mm/slub.c:2816 [inline]
>>   __pcs_replace_empty_main+0x2ed/0x640 mm/slub.c:4652
>>   alloc_from_pcs mm/slub.c:4750 [inline]
>>   slab_alloc_node mm/slub.c:4884 [inline]
>>   __do_kmalloc_node mm/slub.c:5295 [inline]
>>   __kmalloc_noprof+0x68d/0x850 mm/slub.c:5308
>>   kmalloc_noprof include/linux/slab.h:954 [inline]
>>   kzalloc_noprof include/linux/slab.h:1188 [inline]
>>   tomoyo_encode2+0x100/0x3e0 security/tomoyo/realpath.c:45
>>   tomoyo_encode+0x29/0x50 security/tomoyo/realpath.c:80
>>   tomoyo_realpath_from_path+0x18c/0x690 security/tomoyo/realpath.c:283
>>   tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
>>   tomoyo_check_open_permission+0x2ab/0x3c0 security/tomoyo/file.c:776
>>   tomoyo_file_open+0x6b/0x90 security/tomoyo/tomoyo.c:334
>>   security_file_open+0x7a/0x1b0 security/security.c:2739
>>   do_dentry_open+0x57e/0x1690 fs/open.c:924
>>   vfs_open+0x82/0x3f0 fs/open.c:1079
>>   do_open fs/namei.c:4699 [inline]
>>   path_openat+0x218a/0x3190 fs/namei.c:4858
>> page last free pid 1 tgid 1 stack trace:
>>   reset_page_owner include/linux/page_owner.h:25 [inline]
>>   __free_pages_prepare mm/page_alloc.c:1397 [inline]
>>   __free_frozen_pages+0x763/0xfc0 mm/page_alloc.c:2938
>>   selinux_genfs_get_sid security/selinux/hooks.c:1364 [inline]
>>   inode_doinit_with_dentry+0x903/0x1320 security/selinux/hooks.c:1563
>>   selinux_d_instantiate+0x26/0x30 security/selinux/hooks.c:6658
>>   security_d_instantiate+0x123/0x190 security/security.c:3704
>>   d_splice_alias_ops+0x92/0x850 fs/dcache.c:3141
>>   kernfs_iop_lookup+0x23f/0x2d0 fs/kernfs/dir.c:1289
>>   lookup_open.isra.0+0x659/0x1080 fs/namei.c:4484
>>   open_last_lookups fs/namei.c:4611 [inline]
>>   path_openat+0x17dd/0x3190 fs/namei.c:4855
>>   do_file_open+0x20c/0x430 fs/namei.c:4887
>>   do_sys_openat2+0x101/0x1d0 fs/open.c:1364
>>   do_sys_open fs/open.c:1370 [inline]
>>   __do_sys_openat fs/open.c:1386 [inline]
>>   __se_sys_openat fs/open.c:1381 [inline]
>>   __x64_sys_openat+0x141/0x200 fs/open.c:1381
>>   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
>>
>> Memory state around the buggy address:
>>   ffff88802b8ddc80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
>>   ffff88802b8ddd00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>>> ffff88802b8ddd80: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
>>                                          ^
>>   ffff88802b8dde00: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
>>   ffff88802b8dde80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
>>
>> Fix the OOB by moving the assignment after free_rd_atomic_resources()
>> so the old array is freed using the old bound. This matches the original
>> ordering in commit 8700e3e7c485 ("Soft RoCE driver").
>>
>> Closes: https://lore.kernel.org/all/365C68B4923F8214+30195a67-0b90-4b92-ab96-2ce41517793c@smail.nju.edu.cn/
>> Fixes: b6bbee0d2438 ("IB/rxe: Properly honor max IRD value for rd/atomic.")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Peiyang He <peiyang_he@smail.nju.edu.cn>
>> Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>
>> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
>> (cherry picked from commit de329533792a373186d79dca1ca120f8fa0afd05)
> Ok, that's the upstream commit, but:
>
>> [This commit is based on the upstream commit 6f7014237405 ("RDMA/rxe: Fix responder UAF on IB_QP_MAX_DEST_RD_ATOMIC modify_qp")]
> What does that mean here?
>
> Why isn't the original backported properly instead?
The original patch cannot be cleanly backported to this older kernel 
version because it depends on the upstream commit `6f7014237405 
("RDMA/rxe: Fix responder UAF on IB_QP_MAX_DEST_RD_ATOMIC modify_qp")`, 
which is not present in this branch.

The corresponding upstream backport is based on that commit. Since the 
prerequisite change is missing here, the original patch does not apply 
cleanly. I therefore made a minimal adjustment to account for the 
differences in the older code base, while keeping the same fix and 
behavior as the upstream change.

So this is not intended to introduce a different fix, but to adapt the 
upstream change so that it can be cleanly backported to this kernel version.

Best Regards,

Zhu Yanjun

>
> thanks,
>
> greg k-h

-- 
Best Regards,
Yanjun.Zhu