PT-2026-51927 · Linux · Linux
Published
2026-06-24
·
Updated
2026-06-24
·
CVE-2026-53033
None
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In the Linux kernel, the following vulnerability has been resolved:
bpf, sockmap: Take state lock for af unix iter
When a BPF iterator program updates a sockmap, there is a race condition in
unix stream bpf update proto() where the
peer pointer can become stale[1]
during a state transition TCP ESTABLISHED -> TCP CLOSE.CPU0 bpf CPU1 close
-------- ----------// unix stream bpf update proto()
sk pair = unix peer(sk)
if (unlikely(!sk pair))
return -EINVAL;
// unix release sock()
skpair = unix peer(sk);
unix peer(sk) = NULL;
sock put(skpair)
sock hold(sk pair) // UaF
More practically, this fix guarantees that the iterator program is
consistently provided with a unix socket that remains stable during
iterator execution.
[1]:
BUG: KASAN: slab-use-after-free in unix stream bpf update proto+0x155/0x490
Write of size 4 at addr ffff8881178c9a00 by task test progs/2231
Call Trace:
dump stack lvl+0x5d/0x80
print report+0x170/0x4f3
kasan report+0xe4/0x1c0
kasan check range+0x125/0x200
unix stream bpf update proto+0x155/0x490
sock map link+0x71c/0xec0
sock map update common+0xbc/0x600
sock map update elem+0x19a/0x1f0
bpf prog bbbf56096cdd4f01 selective dump unix+0x20c/0x217
bpf iter run prog+0x21e/0xae0
bpf iter unix seq show+0x1e0/0x2a0
bpf seq read+0x42c/0x10d0
vfs read+0x171/0xb20
ksys read+0xff/0x200
do syscall 64+0xf7/0x5e0
entry SYSCALL 64 after hwframe+0x76/0x7e
Allocated by task 2236:
kasan save stack+0x30/0x50
kasan save track+0x14/0x30
kasan slab alloc+0x63/0x80
kmem cache alloc noprof+0x1d5/0x680
sk prot alloc+0x59/0x210
sk alloc+0x34/0x470
unix create1+0x86/0x8a0
unix stream connect+0x318/0x15b0
sys connect+0xfd/0x130
x64 sys connect+0x72/0xd0
do syscall 64+0xf7/0x5e0
entry SYSCALL 64 after hwframe+0x76/0x7e
Freed by task 2236:
kasan save stack+0x30/0x50
kasan save track+0x14/0x30
kasan save free info+0x3b/0x70
kasan slab free+0x47/0x70
kmem cache free+0x11c/0x590
sk destruct+0x432/0x6e0
unix release sock+0x9b3/0xf60
unix release+0x8a/0xf0
sock release+0xb0/0x270
sock close+0x18/0x20
fput+0x36e/0xac0
fput close sync+0xe5/0x1a0
x64 sys close+0x7d/0xd0
do syscall 64+0xf7/0x5e0
entry SYSCALL 64 after hwframe+0x76/0x7e
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Related Identifiers
Affected Products
Linux