Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: ipv6: ioam: refresh hdr pointer before ioam6_event() Reported by Sashiko: In ipv6_hop_ioam(), the hdr pointer is initialized to point into the skb's linear data buffer. Later, the code calls skb_ensure_writable(), which might reallocate the buffer: if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len)) goto drop; /* Trace pointer may have changed */ trace = (struct ioam6_trace_hdr *)(skb_network_header(skb) + optoff + sizeof(*hdr)); ioam6_fill_trace_data(skb, ns, trace, true); ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev), GFP_ATOMIC, (void *)trace, hdr->opt_len - 2); If the skb is cloned or lacks sufficient linear headroom, skb_ensure_writable() will invoke pskb_expand_head(), which reallocates the skb's data buffer and frees the old one, invalidating pointers to it. While the code recalculates the trace pointer immediately after the call to skb_ensure_writable(), it fails to recalculate the hdr pointer. This patch fixes the above by recalculating the hdr pointer before passing hdr->opt_len to ioam6_event(), so that we avoid any UaF.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected f655c78d6225f585ef60a9d93ffb79d507ff3ad3 before 769723124b7c3b2bfea4cf68ad292698b87c8d01; affected f655c78d6225f585ef60a9d93ffb79d507ff3ad3 before 24de676da63c1122d2c13b0d546238b66d1b4e62; affected f655c78d6225f585ef60a9d93ffb79d507ff3ad3 before 5af905aa8e91ff8d94572a1e089558f21dcf24ed; affected f655c78d6225f585ef60a9d93ffb79d507ff3ad3 before e46e6bc97fb1f339730ff1ba74267fbf48e7a422 |
| Linux / Linux | affected 6.9; unaffected 0 before 6.9; unaffected 6.12.92 through 6.12.*; unaffected 6.18.34 through 6.18.*; unaffected 7.0.11 through 7.0.*; unaffected 7.1 through * |
CWE
No CWE identifiers supplied.