CVE-2026-22979
Gravedad:
Pendiente de análisis
Tipo:
No Disponible / Otro tipo
Fecha de publicación:
23/01/2026
Última modificación:
23/01/2026
Descripción
*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br />
<br />
net: fix memory leak in skb_segment_list for GRO packets<br />
<br />
When skb_segment_list() is called during packet forwarding, it handles<br />
packets that were aggregated by the GRO engine.<br />
<br />
Historically, the segmentation logic in skb_segment_list assumes that<br />
individual segments are split from a parent SKB and may need to carry<br />
their own socket memory accounting. Accordingly, the code transfers<br />
truesize from the parent to the newly created segments.<br />
<br />
Prior to commit ed4cccef64c1 ("gro: fix ownership transfer"), this<br />
truesize subtraction in skb_segment_list() was valid because fragments<br />
still carry a reference to the original socket.<br />
<br />
However, commit ed4cccef64c1 ("gro: fix ownership transfer") changed<br />
this behavior by ensuring that fraglist entries are explicitly<br />
orphaned (skb->sk = NULL) to prevent illegal orphaning later in the<br />
stack. This change meant that the entire socket memory charge remained<br />
with the head SKB, but the corresponding accounting logic in<br />
skb_segment_list() was never updated.<br />
<br />
As a result, the current code unconditionally adds each fragment&#39;s<br />
truesize to delta_truesize and subtracts it from the parent SKB. Since<br />
the fragments are no longer charged to the socket, this subtraction<br />
results in an effective under-count of memory when the head is freed.<br />
This causes sk_wmem_alloc to remain non-zero, preventing socket<br />
destruction and leading to a persistent memory leak.<br />
<br />
The leak can be observed via KMEMLEAK when tearing down the networking<br />
environment:<br />
<br />
unreferenced object 0xffff8881e6eb9100 (size 2048):<br />
comm "ping", pid 6720, jiffies 4295492526<br />
backtrace:<br />
kmem_cache_alloc_noprof+0x5c6/0x800<br />
sk_prot_alloc+0x5b/0x220<br />
sk_alloc+0x35/0xa00<br />
inet6_create.part.0+0x303/0x10d0<br />
__sock_create+0x248/0x640<br />
__sys_socket+0x11b/0x1d0<br />
<br />
Since skb_segment_list() is exclusively used for SKB_GSO_FRAGLIST<br />
packets constructed by GRO, the truesize adjustment is removed.<br />
<br />
The call to skb_release_head_state() must be preserved. As documented in<br />
commit cf673ed0e057 ("net: fix fraglist segmentation reference count<br />
leak"), it is still required to correctly drop references to SKB<br />
extensions that may be overwritten during __copy_skb_header().
Impacto
Referencias a soluciones, herramientas e información
- https://git.kernel.org/stable/c/0b27828ebd1ed3107d7929c3737adbe862e99e74
- https://git.kernel.org/stable/c/238e03d0466239410b72294b79494e43d4fabe77
- https://git.kernel.org/stable/c/3264881431e308b9c72cb8a0159d57a56d67dd79
- https://git.kernel.org/stable/c/88bea149db2057112af3aaf63534b24fab5858ab
- https://git.kernel.org/stable/c/c114a32a2e70b82d447f409f7ffcfa3058f9d5bd



