Dear developers and maintainers,
We found a bug through our modified Syzkaller. Kernel version is
b401b621758,
Linux 6.8-rc5. The C reproducer and kernel config are attached.
KASAN report is listed below
```
==================================================================
BUG: KASAN: slab-out-of-bounds in strlen+0x7d/0xa0 lib/string.c:418
Read of size 1 at addr ffff8881119c4781 by task syz-executor665/8107
CPU: 1 PID: 8107 Comm: syz-executor665 Not tainted 6.7.0-rc7 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:364 [inline]
print_report+0xc1/0x5e0 mm/kasan/report.c:475
kasan_report+0xbe/0xf0 mm/kasan/report.c:588
strlen+0x7d/0xa0 lib/string.c:418
__fortify_strlen include/linux/fortify-string.h:210 [inline]
in4_pton+0xa3/0x3f0 net/core/utils.c:130
bond_option_arp_ip_targets_set+0xc2/0x910
drivers/net/bonding/bond_options.c:1201
__bond_opt_set+0x2a4/0x1030 drivers/net/bonding/bond_options.c:767
__bond_opt_set_notify+0x48/0x150 drivers/net/bonding/bond_options.c:792
bond_opt_tryset_rtnl+0xda/0x160 drivers/net/bonding/bond_options.c:817
bonding_sysfs_store_option+0xa1/0x120 drivers/net/bonding/bond_sysfs.c:156
dev_attr_store+0x54/0x80 drivers/base/core.c:2366
sysfs_kf_write+0x114/0x170 fs/sysfs/file.c:136
kernfs_fop_write_iter+0x337/0x500 fs/kernfs/file.c:334
call_write_iter include/linux/fs.h:2020 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x96a/0xd80 fs/read_write.c:584
ksys_write+0x122/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f797835cfcd
Code: 28 c3 e8 46 1e 00 00 66 0f 1f 44 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffff464ffb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffff46501b8 RCX: 00007f797835cfcd
RDX: 00000000000000f5 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 00007ffff46501b8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffff46501a8 R14: 00007f79783da530 R15: 0000000000000001
</TASK>
Allocated by task 8107:
kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:374 [inline]
____kasan_kmalloc mm/kasan/common.c:333 [inline]
__kasan_kmalloc+0xa3/0xb0 mm/kasan/common.c:383
kasan_kmalloc include/linux/kasan.h:198 [inline]
__do_kmalloc_node mm/slab_common.c:1007 [inline]
__kmalloc_node_track_caller+0x5e/0xd0 mm/slab_common.c:1027
kstrndup+0x72/0x110 mm/util.c:108
bonding_sysfs_store_option+0x66/0x120 drivers/net/bonding/bond_sysfs.c:153
dev_attr_store+0x54/0x80 drivers/base/core.c:2366
sysfs_kf_write+0x114/0x170 fs/sysfs/file.c:136
kernfs_fop_write_iter+0x337/0x500 fs/kernfs/file.c:334
call_write_iter include/linux/fs.h:2020 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x96a/0xd80 fs/read_write.c:584
ksys_write+0x122/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
The buggy address belongs to the object at ffff8881119c4780
which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes to the right of
allocated 1-byte region [ffff8881119c4780, ffff8881119c4781)
The buggy address belongs to the physical page:
page:ffffea0004467100 refcount:1 mapcount:0 mapping:0000000000000000
index:0xffff8881119c4fc1 pfn:0x1119c4
flags: 0x57ff00000000800(slab|node=1|zone=2|lastcpupid=0x7ff)
page_type: 0x3f()
raw: 057ff00000000800 ffff888013040100 ffffea000405a650 ffffea0004156b90
raw: ffff8881119c4fc1 ffff8881119c4000 000000010000003f 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
0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE),
pid 25, tgid 25 (kworker/u6:0), ts 73787966798, free_ts 73774684635
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2d9/0x350 mm/page_alloc.c:1537
prep_new_page mm/page_alloc.c:1544 [inline]
get_page_from_freelist+0xd38/0x2fa0 mm/page_alloc.c:3312
__alloc_pages+0x21d/0x21f0 mm/page_alloc.c:4568
__alloc_pages_node include/linux/gfp.h:238 [inline]
kmem_getpages mm/slab.c:1356 [inline]
cache_grow_begin+0x9b/0x3c0 mm/slab.c:2550
cache_alloc_refill+0x289/0x3a0 mm/slab.c:2923
____cache_alloc mm/slab.c:2999 [inline]
____cache_alloc mm/slab.c:2982 [inline]
__do_cache_alloc mm/slab.c:3185 [inline]
slab_alloc_node mm/slab.c:3230 [inline]
__kmem_cache_alloc_node+0x374/0x420 mm/slab.c:3521
__do_kmalloc_node mm/slab_common.c:1006 [inline]
__kmalloc_node+0x50/0xd0 mm/slab_common.c:1014
kmalloc_array_node include/linux/slab.h:698 [inline]
kcalloc_node include/linux/slab.h:703 [inline]
memcg_alloc_slab_cgroups+0x10e/0x210 mm/memcontrol.c:2968
account_slab mm/slab.h:637 [inline]
kmem_getpages mm/slab.c:1364 [inline]
cache_grow_begin+0x349/0x3c0 mm/slab.c:2550
cache_alloc_refill+0x289/0x3a0 mm/slab.c:2923
____cache_alloc mm/slab.c:2999 [inline]
____cache_alloc mm/slab.c:2982 [inline]
__do_cache_alloc mm/slab.c:3182 [inline]
slab_alloc_node mm/slab.c:3230 [inline]
kmem_cache_alloc_node+0x3e1/0x4a0 mm/slab.c:3509
alloc_task_struct_node kernel/fork.c:173 [inline]
dup_task_struct kernel/fork.c:1110 [inline]
copy_process+0x3f6/0x73e0 kernel/fork.c:2332
kernel_clone+0xeb/0x8c0 kernel/fork.c:2907
user_mode_thread+0xb4/0xf0 kernel/fork.c:2985
call_usermodehelper_exec_work kernel/umh.c:172 [inline]
call_usermodehelper_exec_work+0xd0/0x180 kernel/umh.c:158
process_one_work+0x878/0x15c0 kernel/workqueue.c:2627
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1137 [inline]
free_unref_page_prepare+0x4c5/0xa60 mm/page_alloc.c:2347
free_unref_page+0x33/0x3d0 mm/page_alloc.c:2487
rcu_do_batch kernel/rcu/tree.c:2158 [inline]
rcu_core+0x817/0x1670 kernel/rcu/tree.c:2431
__do_softirq+0x1d4/0x85e kernel/softirq.c:553
Memory state around the buggy address:
ffff8881119c4680: fa fb fb fb fc fc fc fc 00 01 fc fc fc fc fc fc
ffff8881119c4700: 00 05 fc fc fc fc fc fc 00 00 00 fc fc fc fc fc
>ffff8881119c4780: 01 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
^
ffff8881119c4800: 00 01 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
ffff8881119c4880: 00 fc fc fc fc fc fc fc 00 01 fc fc fc fc fc fc
==================================================================
```
We analyzed the cause of this bug. In the function
"bond_option_arp_ip_targets_set" in
drivers/net/bonding/bond_options.c, newval->string can be controlled
by users. If string
is empty, newval->string+1 points to the address after newval->string,
causing potential
info leak.
One possible fix is to check before calling in4_pton, whether
strnlen(newval->string) > 1.
If you have any questions or require more information, please feel
free to contact us.
Reported by Yue Sun <[email protected]>
Best Regards,
Yue
On Fri, Mar 1, 2024 at 3:41 AM Sam Sun <[email protected]> wrote:
>
> Dear developers and maintainers,
>
> We found a bug through our modified Syzkaller. Kernel version is b401b621758,
> Linux 6.8-rc5. The C reproducer and kernel config are attached.
>
> KASAN report is listed below
>
> ```
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in strlen+0x7d/0xa0 lib/string.c:418
> Read of size 1 at addr ffff8881119c4781 by task syz-executor665/8107
>
> CPU: 1 PID: 8107 Comm: syz-executor665 Not tainted 6.7.0-rc7 #1
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
> print_address_description mm/kasan/report.c:364 [inline]
> print_report+0xc1/0x5e0 mm/kasan/report.c:475
> kasan_report+0xbe/0xf0 mm/kasan/report.c:588
> strlen+0x7d/0xa0 lib/string.c:418
> __fortify_strlen include/linux/fortify-string.h:210 [inline]
> in4_pton+0xa3/0x3f0 net/core/utils.c:130
> bond_option_arp_ip_targets_set+0xc2/0x910 drivers/net/bonding/bond_options.c:1201
> __bond_opt_set+0x2a4/0x1030 drivers/net/bonding/bond_options.c:767
> __bond_opt_set_notify+0x48/0x150 drivers/net/bonding/bond_options.c:792
> bond_opt_tryset_rtnl+0xda/0x160 drivers/net/bonding/bond_options.c:817
> bonding_sysfs_store_option+0xa1/0x120 drivers/net/bonding/bond_sysfs.c:156
> dev_attr_store+0x54/0x80 drivers/base/core.c:2366
> sysfs_kf_write+0x114/0x170 fs/sysfs/file.c:136
> kernfs_fop_write_iter+0x337/0x500 fs/kernfs/file.c:334
> call_write_iter include/linux/fs.h:2020 [inline]
> new_sync_write fs/read_write.c:491 [inline]
> vfs_write+0x96a/0xd80 fs/read_write.c:584
> ksys_write+0x122/0x250 fs/read_write.c:637
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x63/0x6b
> RIP: 0033:0x7f797835cfcd
> Code: 28 c3 e8 46 1e 00 00 66 0f 1f 44 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffff464ffb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> RAX: ffffffffffffffda RBX: 00007ffff46501b8 RCX: 00007f797835cfcd
> RDX: 00000000000000f5 RSI: 0000000020000140 RDI: 0000000000000003
> RBP: 0000000000000001 R08: 0000000000000000 R09: 00007ffff46501b8
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
> R13: 00007ffff46501a8 R14: 00007f79783da530 R15: 0000000000000001
> </TASK>
>
> All
>
> We analyzed the cause of this bug. In the function "bond_option_arp_ip_targets_set" in
> drivers/net/bonding/bond_options.c, newval->string can be controlled by users. If string
>
> is empty, newval->string+1 points to the address after newval->string, causing potential
>
> info leak.
>
> One possible fix is to check before calling in4_pton, whether strnlen(newval->string) > 1.
>
> If you have any questions or require more information, please feel
> free to contact us.
>
> Reported by Yue Sun <[email protected]>
>
Thanks for the report and analysis.
Are you willing to provide a patch ?
You would get more credits than a "Reported-by:" tag :)
Thanks
On Fri, Mar 1, 2024 at 4:18 PM Eric Dumazet <[email protected]> wrote:
>
> On Fri, Mar 1, 2024 at 3:41 AM Sam Sun <[email protected]> wrote:
> >
> > Dear developers and maintainers,
> >
> > We found a bug through our modified Syzkaller. Kernel version is b401b621758,
> > Linux 6.8-rc5. The C reproducer and kernel config are attached.
> >
> > KASAN report is listed below
> >
> > ```
> > ==================================================================
> > BUG: KASAN: slab-out-of-bounds in strlen+0x7d/0xa0 lib/string.c:418
> > Read of size 1 at addr ffff8881119c4781 by task syz-executor665/8107
> >
> > CPU: 1 PID: 8107 Comm: syz-executor665 Not tainted 6.7.0-rc7 #1
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> > Call Trace:
> > <TASK>
> > __dump_stack lib/dump_stack.c:88 [inline]
> > dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
> > print_address_description mm/kasan/report.c:364 [inline]
> > print_report+0xc1/0x5e0 mm/kasan/report.c:475
> > kasan_report+0xbe/0xf0 mm/kasan/report.c:588
> > strlen+0x7d/0xa0 lib/string.c:418
> > __fortify_strlen include/linux/fortify-string.h:210 [inline]
> > in4_pton+0xa3/0x3f0 net/core/utils.c:130
> > bond_option_arp_ip_targets_set+0xc2/0x910 drivers/net/bonding/bond_options.c:1201
> > __bond_opt_set+0x2a4/0x1030 drivers/net/bonding/bond_options.c:767
> > __bond_opt_set_notify+0x48/0x150 drivers/net/bonding/bond_options.c:792
> > bond_opt_tryset_rtnl+0xda/0x160 drivers/net/bonding/bond_options.c:817
> > bonding_sysfs_store_option+0xa1/0x120 drivers/net/bonding/bond_sysfs.c:156
> > dev_attr_store+0x54/0x80 drivers/base/core.c:2366
> > sysfs_kf_write+0x114/0x170 fs/sysfs/file.c:136
> > kernfs_fop_write_iter+0x337/0x500 fs/kernfs/file.c:334
> > call_write_iter include/linux/fs.h:2020 [inline]
> > new_sync_write fs/read_write.c:491 [inline]
> > vfs_write+0x96a/0xd80 fs/read_write.c:584
> > ksys_write+0x122/0x250 fs/read_write.c:637
> > do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
> > entry_SYSCALL_64_after_hwframe+0x63/0x6b
> > RIP: 0033:0x7f797835cfcd
> > Code: 28 c3 e8 46 1e 00 00 66 0f 1f 44 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
> > RSP: 002b:00007ffff464ffb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> > RAX: ffffffffffffffda RBX: 00007ffff46501b8 RCX: 00007f797835cfcd
> > RDX: 00000000000000f5 RSI: 0000000020000140 RDI: 0000000000000003
> > RBP: 0000000000000001 R08: 0000000000000000 R09: 00007ffff46501b8
> > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
> > R13: 00007ffff46501a8 R14: 00007f79783da530 R15: 0000000000000001
> > </TASK>
> >
> > All
>
>
> >
> > We analyzed the cause of this bug. In the function "bond_option_arp_ip_targets_set" in
> > drivers/net/bonding/bond_options.c, newval->string can be controlled by users. If string
> >
> > is empty, newval->string+1 points to the address after newval->string, causing potential
> >
> > info leak.
> >
> > One possible fix is to check before calling in4_pton, whether strnlen(newval->string) > 1.
> >
> > If you have any questions or require more information, please feel
> > free to contact us.
> >
> > Reported by Yue Sun <[email protected]>
> >
>
> Thanks for the report and analysis.
>
> Are you willing to provide a patch ?
>
> You would get more credits than a "Reported-by:" tag :)
>
> Thanks
Dear Eric,
Thanks for letting me provide a patch! One possible patch
is listed below.
diff --git a/drivers/net/bonding/bond_options.c
b/drivers/net/bonding/bond_options.c
index f3f27f0bd2a6..a6d01055f455 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c
@@ -1198,7 +1198,7 @@ static int bond_option_arp_ip_targets_set(struct
bonding *bond,
__be32 target;
if (newval->string) {
- if (!in4_pton(newval->string+1, -1, (u8 *)&target, -1, NULL)) {
+ if (!strlen(newval->string) || !in4_pton(newval->string+1,
-1, (u8 *)&target, -1, NULL)) {
netdev_err(bond->dev, "invalid ARP target %pI4 specified\n",
&target);
return ret;
This patch was tested on kernel commit b401b621758,
tag Linux 6.8-rc5 against the C repro listed in previous
email.
If you have any questions, please contact us.
Best Regards,
Yue
Hi Sam,
On Fri, Mar 1, 2024 at 11:23 PM Sam Sun <[email protected]> wrote:
>
> On Fri, Mar 1, 2024 at 4:18 PM Eric Dumazet <[email protected]> wrote:
> >
> > On Fri, Mar 1, 2024 at 3:41 AM Sam Sun <[email protected]> wrote:
> > >
> > > Dear developers and maintainers,
> > >
> > > We found a bug through our modified Syzkaller. Kernel version is b401b621758,
> > > Linux 6.8-rc5. The C reproducer and kernel config are attached.
> > >
> > > KASAN report is listed below
> > >
> > > ```
> > > ==================================================================
> > > BUG: KASAN: slab-out-of-bounds in strlen+0x7d/0xa0 lib/string.c:418
> > > Read of size 1 at addr ffff8881119c4781 by task syz-executor665/8107
> > >
> > > CPU: 1 PID: 8107 Comm: syz-executor665 Not tainted 6.7.0-rc7 #1
> > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> > > Call Trace:
> > > <TASK>
> > > __dump_stack lib/dump_stack.c:88 [inline]
> > > dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
> > > print_address_description mm/kasan/report.c:364 [inline]
> > > print_report+0xc1/0x5e0 mm/kasan/report.c:475
> > > kasan_report+0xbe/0xf0 mm/kasan/report.c:588
> > > strlen+0x7d/0xa0 lib/string.c:418
> > > __fortify_strlen include/linux/fortify-string.h:210 [inline]
> > > in4_pton+0xa3/0x3f0 net/core/utils.c:130
> > > bond_option_arp_ip_targets_set+0xc2/0x910 drivers/net/bonding/bond_options.c:1201
> > > __bond_opt_set+0x2a4/0x1030 drivers/net/bonding/bond_options.c:767
> > > __bond_opt_set_notify+0x48/0x150 drivers/net/bonding/bond_options.c:792
> > > bond_opt_tryset_rtnl+0xda/0x160 drivers/net/bonding/bond_options.c:817
> > > bonding_sysfs_store_option+0xa1/0x120 drivers/net/bonding/bond_sysfsc:156
> > > dev_attr_store+0x54/0x80 drivers/base/core.c:2366
> > > sysfs_kf_write+0x114/0x170 fs/sysfs/file.c:136
> > > kernfs_fop_write_iter+0x337/0x500 fs/kernfs/file.c:334
> > > call_write_iter include/linux/fs.h:2020 [inline]
> > > new_sync_write fs/read_write.c:491 [inline]
> > > vfs_write+0x96a/0xd80 fs/read_write.c:584
> > > ksys_write+0x122/0x250 fs/read_write.c:637
> > > do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> > > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
> > > entry_SYSCALL_64_after_hwframe+0x63/0x6b
> > > RIP: 0033:0x7f797835cfcd
> > > Code: 28 c3 e8 46 1e 00 00 66 0f 1f 44 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
> > > RSP: 002b:00007ffff464ffb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> > > RAX: ffffffffffffffda RBX: 00007ffff46501b8 RCX: 00007f797835cfcd
> > > RDX: 00000000000000f5 RSI: 0000000020000140 RDI: 0000000000000003
> > > RBP: 0000000000000001 R08: 0000000000000000 R09: 00007ffff46501b8
> > > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
> > > R13: 00007ffff46501a8 R14: 00007f79783da530 R15: 0000000000000001
> > > </TASK>
> > >
> > > All
> >
> >
> > >
> > > We analyzed the cause of this bug. In the function "bond_option_arp_ip_targets_set" in
> > > drivers/net/bonding/bond_options.c, newval->string can be controlled by users. If string
> > >
> > > is empty, newval->string+1 points to the address after newval->string, causing potential
> > >
> > > info leak.
> > >
> > > One possible fix is to check before calling in4_pton, whether strnlen(newval->string) > 1.
> > >
> > > If you have any questions or require more information, please feel
> > > free to contact us.
> > >
> > > Reported by Yue Sun <[email protected]>
> > >
> >
> > Thanks for the report and analysis.
> >
> > Are you willing to provide a patch ?
> >
> > You would get more credits than a "Reported-by:" tag :)
> >
> > Thanks
>
> Dear Eric,
>
> Thanks for letting me provide a patch! One possible patch
> is listed below.
>
> diff --git a/drivers/net/bonding/bond_options.c
> b/drivers/net/bonding/bond_options.c
> index f3f27f0bd2a6..a6d01055f455 100644
> --- a/drivers/net/bonding/bond_options.c
> +++ b/drivers/net/bonding/bond_options.c
> @@ -1198,7 +1198,7 @@ static int bond_option_arp_ip_targets_set(struct
> bonding *bond,
> __be32 target;
>
> if (newval->string) {
> - if (!in4_pton(newval->string+1, -1, (u8 *)&target, -1, NULL)) {
> + if (!strlen(newval->string) || !in4_pton(newval->string+1,
> -1, (u8 *)&target, -1, NULL)) {
> netdev_err(bond->dev, "invalid ARP target %pI4 specified\n",
> &target);
> return ret;
You could submit the patch targetting at the latest net tree on your
own instead of replying to this thread. And then people will review it
soon :)
Thanks,
Jason
>
> This patch was tested on kernel commit b401b621758,
> tag Linux 6.8-rc5 against the C repro listed in previous
> email.
>
> If you have any questions, please contact us.
>
> Best Regards,
> Yue
>
On Mon, Mar 4, 2024 at 11:20 AM Jason Xing <[email protected]> wrote:
>
> Hi Sam,
>
> On Fri, Mar 1, 2024 at 11:23 PM Sam Sun <[email protected]> wrote:
> >
> > On Fri, Mar 1, 2024 at 4:18 PM Eric Dumazet <[email protected]> wrote:
> > >
> > > On Fri, Mar 1, 2024 at 3:41 AM Sam Sun <[email protected]> wrote:
> > > >
> > > > Dear developers and maintainers,
> > > >
> > > > We found a bug through our modified Syzkaller. Kernel version is b401b621758,
> > > > Linux 6.8-rc5. The C reproducer and kernel config are attached.
> > > >
> > > > KASAN report is listed below
> > > >
> > > > ```
> > > > ==================================================================
> > > > BUG: KASAN: slab-out-of-bounds in strlen+0x7d/0xa0 lib/string.c:418
> > > > Read of size 1 at addr ffff8881119c4781 by task syz-executor665/8107
> > > >
> > > > CPU: 1 PID: 8107 Comm: syz-executor665 Not tainted 6.7.0-rc7 #1
> > > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> > > > Call Trace:
> > > > <TASK>
> > > > __dump_stack lib/dump_stack.c:88 [inline]
> > > > dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
> > > > print_address_description mm/kasan/report.c:364 [inline]
> > > > print_report+0xc1/0x5e0 mm/kasan/report.c:475
> > > > kasan_report+0xbe/0xf0 mm/kasan/report.c:588
> > > > strlen+0x7d/0xa0 lib/string.c:418
> > > > __fortify_strlen include/linux/fortify-string.h:210 [inline]
> > > > in4_pton+0xa3/0x3f0 net/core/utils.c:130
> > > > bond_option_arp_ip_targets_set+0xc2/0x910 drivers/net/bonding/bond_options.c:1201
> > > > __bond_opt_set+0x2a4/0x1030 drivers/net/bonding/bond_options.c:767
> > > > __bond_opt_set_notify+0x48/0x150 drivers/net/bonding/bond_options.c:792
> > > > bond_opt_tryset_rtnl+0xda/0x160 drivers/net/bonding/bond_options.c:817
> > > > bonding_sysfs_store_option+0xa1/0x120 drivers/net/bonding/bond_sysfs.c:156
> > > > dev_attr_store+0x54/0x80 drivers/base/core.c:2366
> > > > sysfs_kf_write+0x114/0x170 fs/sysfs/file.c:136
> > > > kernfs_fop_write_iter+0x337/0x500 fs/kernfs/file.c:334
> > > > call_write_iter include/linux/fs.h:2020 [inline]
> > > > new_sync_write fs/read_write.c:491 [inline]
> > > > vfs_write+0x96a/0xd80 fs/read_write.c:584
> > > > ksys_write+0x122/0x250 fs/read_write.c:637
> > > > do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> > > > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
> > > > entry_SYSCALL_64_after_hwframe+0x63/0x6b
> > > > RIP: 0033:0x7f797835cfcd
> > > > Code: 28 c3 e8 46 1e 00 00 66 0f 1f 44 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
> > > > RSP: 002b:00007ffff464ffb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> > > > RAX: ffffffffffffffda RBX: 00007ffff46501b8 RCX: 00007f797835cfcd
> > > > RDX: 00000000000000f5 RSI: 0000000020000140 RDI: 0000000000000003
> > > > RBP: 0000000000000001 R08: 0000000000000000 R09: 00007ffff46501b8
> > > > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
> > > > R13: 00007ffff46501a8 R14: 00007f79783da530 R15: 0000000000000001
> > > > </TASK>
> > > >
> > > > All
> > >
> > >
> > > >
> > > > We analyzed the cause of this bug. In the function "bond_option_arp_ip_targets_set" in
> > > > drivers/net/bonding/bond_options.c, newval->string can be controlled by users. If string
> > > >
> > > > is empty, newval->string+1 points to the address after newval->string, causing potential
> > > >
> > > > info leak.
> > > >
> > > > One possible fix is to check before calling in4_pton, whether strnlen(newval->string) > 1.
> > > >
> > > > If you have any questions or require more information, please feel
> > > > free to contact us.
> > > >
> > > > Reported by Yue Sun <[email protected]>
> > > >
> > >
> > > Thanks for the report and analysis.
> > >
> > > Are you willing to provide a patch ?
> > >
> > > You would get more credits than a "Reported-by:" tag :)
> > >
> > > Thanks
> >
> > Dear Eric,
> >
> > Thanks for letting me provide a patch! One possible patch
> > is listed below.
> >
> > diff --git a/drivers/net/bonding/bond_options.c
> > b/drivers/net/bonding/bond_options.c
> > index f3f27f0bd2a6..a6d01055f455 100644
> > --- a/drivers/net/bonding/bond_options.c
> > +++ b/drivers/net/bonding/bond_options.c
> > @@ -1198,7 +1198,7 @@ static int bond_option_arp_ip_targets_set(struct
> > bonding *bond,
> > __be32 target;
> >
> > if (newval->string) {
> > - if (!in4_pton(newval->string+1, -1, (u8 *)&target, -1, NULL)) {
> > + if (!strlen(newval->string) || !in4_pton(newval->string+1,
> > -1, (u8 *)&target, -1, NULL)) {
> > netdev_err(bond->dev, "invalid ARP target %pI4 specified\n",
> > &target);
> > return ret;
>
> You could submit the patch targetting at the latest net tree on your
> own instead of replying to this thread. And then people will review it
> soon :)
>
> Thanks,
> Jason
>
Hi Jason,
Thanks for replying! Since it is my first time committing a patch, I
don't know the standard procedure of patch submission. I saw people
discuss patches through emails so I replied to the thread. I will
check kernel documentation on submitting patches.
Best Regards,
Sam