Description
In the Linux kernel, the following vulnerability has been resolved: mpls: reload header after pskb_may_pull() mpls_select_multipath() calls mpls_multipath_hash() to choose a nexthop when an MPLS route has multiple nexthops. While walking the MPLS label stack, the hash routine caches hdr for the current label. After finding the bottom-of-stack label, it calls pskb_may_pull() before reading the inner IP header. If an skb is constructed with the inner IP header in nonlinear data and insufficient tailroom in the linear head, pskb_may_pull() calls pskb_expand_head() to replace the skb head and free the old one. This leaves hdr pointing to freed memory. The IPv6 path can invalidate hdr again when it performs a second pull for the larger header. The issue was found through static analysis. A reproducer sending a legal Geneve packet through a bareudp/MPLS multipath setup triggered the same KASAN report in 2 of 2 unpatched runs: BUG: KASAN: slab-use-after-free in mpls_select_multipath Read of size 1 at addr ffff88800ecc6e20 by task ksoftirqd/1/23 Call Trace: mpls_select_multipath mpls_forward __netif_receive_skb_list_core netif_receive_skb_list_internal napi_complete_done gro_cell_poll __napi_poll net_rx_action Freed by task 23: kfree pskb_expand_head __pskb_pull_tail mpls_select_multipath Reload hdr from the current skb head after each successful pull before deriving the inner IPv4 or IPv6 header pointer.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
9f427a0e474a67b454420c131709600d44850486 to < aa4fe0b450a461aa1162fe8375f5d28f4c957df8affected9f427a0e474a67b454420c131709600d44850486 to < b1c0783b2facc398437ad8f8b86c636d7a78f8dbaffected9f427a0e474a67b454420c131709600d44850486 to < bfaaff99238326166694354a63a76c02563f98b1affected9f427a0e474a67b454420c131709600d44850486 to < d9640239827d6d0cb84263b590f7a4f1596c17ebaffected9f427a0e474a67b454420c131709600d44850486 to < fed638a248116b8a249bd4202d28e5934bdc65adaffected9f427a0e474a67b454420c131709600d44850486 to < d82b90a38c2ca8a0694428eab0e9551c23f2447daffected9f427a0e474a67b454420c131709600d44850486 to < 49d38c1b4390412f8950d33dfaee0ccbd17beb81affected9f427a0e474a67b454420c131709600d44850486 to < 29e63b8d9fc150cc191b1c6eb7e16e1247e1b650affectedad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9ebaffected4.9.8 to < 4.10affected
Linux Linux
Default version status: affected
4.10affected0 to < 4.10unaffected5.10.270 to ≤ 5.10.*unaffected5.15.221 to ≤ 5.15.*unaffected6.1.188 to ≤ 6.1.*unaffected6.6.157 to ≤ 6.6.*unaffected6.12.109 to ≤ 6.12.*unaffected6.18.50 to ≤ 6.18.*unaffected7.2.4 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/aa4fe0b450a461aa1162fe8375f5d28f4c957df8 ↗
- https://git.kernel.org/stable/c/b1c0783b2facc398437ad8f8b86c636d7a78f8db ↗
- https://git.kernel.org/stable/c/bfaaff99238326166694354a63a76c02563f98b1 ↗
- https://git.kernel.org/stable/c/d9640239827d6d0cb84263b590f7a4f1596c17eb ↗
- https://git.kernel.org/stable/c/fed638a248116b8a249bd4202d28e5934bdc65ad ↗
- https://git.kernel.org/stable/c/d82b90a38c2ca8a0694428eab0e9551c23f2447d ↗
- https://git.kernel.org/stable/c/49d38c1b4390412f8950d33dfaee0ccbd17beb81 ↗
- https://git.kernel.org/stable/c/29e63b8d9fc150cc191b1c6eb7e16e1247e1b650 ↗