Description
In the Linux kernel, the following vulnerability has been resolved: xfrm: Check for underflow in xfrm_state_mtu Leo Lin reported OOB write issue in esp component: xfrm_state_mtu() returns u32 but performs its arithmetic in unsigned modulo-2^32 space using an attacker-influenced "header_len + authsize + net_adj" subtracted from a small "mtu" argument. A nobody user can install an IPv4 ESP tunnel SA with a large authentication key (XFRMA_ALG_AUTH_TRUNC, e.g. hmac(sha512), 64-byte key, 64-byte trunc), configure a small interface MTU (68 bytes), and set XFRMA_TFCPAD to a large value. When a single UDP datagram is then sent through the tunnel, xfrm_state_mtu() underflows to a near-2^32 value, and esp_output() consumes it as a signed int via: padto = min(x->tfcpad, xfrm_state_mtu(x, mtu_cached)) esp.tfclen = padto - skb->len (assigned to int) esp.tfclen ends up negative (e.g. -207). It is sign-extended to size_t when passed to memset() inside esp_output_fill_trailer(), producing a ~16 EB write of zeroes at skb_tail_pointer(skb). KASAN logs it as "Write of size 18446744073709551537 at addr ffff888...". Check for underflow and return 1. This causes the sendmsg attempt to fail with ENETUNREACH.
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
c5c2523893747f88a83376abad310c8ad13f7197 to < 8014f70c4e6e5ab101ae3860a614e65e988372e3affectedc5c2523893747f88a83376abad310c8ad13f7197 to < 1021d2877b689a648b27815c854557a917122e93affectedc5c2523893747f88a83376abad310c8ad13f7197 to < 2a41b1b31c61c52b972278ce1732a1443f5e89edaffectedc5c2523893747f88a83376abad310c8ad13f7197 to < fccd685b32df5aaf6bad4381eeda216468e283f0affectedc5c2523893747f88a83376abad310c8ad13f7197 to < 820e501be8aee4b365d218d83227b314309c5fdaaffectedc5c2523893747f88a83376abad310c8ad13f7197 to < 82ac903e0b519849647657b8c48d21237ada06a2affectedc5c2523893747f88a83376abad310c8ad13f7197 to < 3db50ceeacb52806d8fe86fb1dfe944df0b9f789affectedc5c2523893747f88a83376abad310c8ad13f7197 to < 742b04d0550b0ec89dcbc99537ec88653bd1ad90affected
Linux Linux
Default version status: affected
2.6.22affected0 to < 2.6.22unaffected5.10.259 to ≤ 5.10.*unaffected5.15.210 to ≤ 5.15.*unaffected6.1.176 to ≤ 6.1.*unaffected6.6.143 to ≤ 6.6.*unaffected6.12.93 to ≤ 6.12.*unaffected6.18.35 to ≤ 6.18.*unaffected7.0.12 to ≤ 7.0.*unaffected7.1 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/8014f70c4e6e5ab101ae3860a614e65e988372e3 ↗
- https://git.kernel.org/stable/c/1021d2877b689a648b27815c854557a917122e93 ↗
- https://git.kernel.org/stable/c/2a41b1b31c61c52b972278ce1732a1443f5e89ed ↗
- https://git.kernel.org/stable/c/fccd685b32df5aaf6bad4381eeda216468e283f0 ↗
- https://git.kernel.org/stable/c/820e501be8aee4b365d218d83227b314309c5fda ↗
- https://git.kernel.org/stable/c/82ac903e0b519849647657b8c48d21237ada06a2 ↗
- https://git.kernel.org/stable/c/3db50ceeacb52806d8fe86fb1dfe944df0b9f789 ↗
- https://git.kernel.org/stable/c/742b04d0550b0ec89dcbc99537ec88653bd1ad90 ↗