From: Jiefeng Zhang The atlantic driver can receive packets with more than MAX_SKB_FRAGS (17) fragments when handling large multi-descriptor packets. This causes an out-of-bounds write in skb_add_rx_frag_netmem() leading to kernel panic. The issue occurs because the driver doesn't check the total number of fragments before calling skb_add_rx_frag(). When a packet requires more than MAX_SKB_FRAGS fragments, the fragment index exceeds the array bounds. Fix by adding a check in __aq_ring_rx_clean() to skip extracting the zeroth fragment when frag_cnt reaches MAX_SKB_FRAGS. This crash occurred in production with an Aquantia AQC113 10G NIC. Stack trace from production environment: ``` RIP: 0010:skb_add_rx_frag_netmem+0x29/0xd0 Code: 90 f3 0f 1e fa 0f 1f 44 00 00 48 89 f8 41 89 ca 48 89 d7 48 63 ce 8b 90 c0 00 00 00 48 c1 e1 04 48 01 ca 48 03 90 c8 00 00 00 <48> 89 7a 30 44 89 52 3c 44 89 42 38 40 f6 c7 01 75 74 48 89 fa 83 RSP: 0018:ffffa9bec02a8d50 EFLAGS: 00010287 RAX: ffff925b22e80a00 RBX: ffff925ad38d2700 RCX: fffffffe0a0c8000 RDX: ffff9258ea95bac0 RSI: ffff925ae0a0c800 RDI: 0000000000037a40 RBP: 0000000000000024 R08: 0000000000000000 R09: 0000000000000021 R10: 0000000000000848 R11: 0000000000000000 R12: ffffa9bec02a8e24 R13: ffff925ad8615570 R14: 0000000000000000 R15: ffff925b22e80a00 FS: 0000000000000000(0000) GS:ffff925e47880000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff9258ea95baf0 CR3: 0000000166022004 CR4: 0000000000f72ef0 PKRU: 55555554 Call Trace: aq_ring_rx_clean+0x175/0xe60 [atlantic] ? aq_ring_rx_clean+0x14d/0xe60 [atlantic] ? aq_ring_tx_clean+0xdf/0x190 [atlantic] ? kmem_cache_free+0x348/0x450 ? aq_vec_poll+0x81/0x1d0 [atlantic] ? __napi_poll+0x28/0x1c0 ? net_rx_action+0x337/0x420 ``` Changes in v2: - Fix fragment overflow by skipping zeroth fragment extraction when frag_cnt reaches MAX_SKB_FRAGS. Signed-off-by: Jiefeng Zhang --- drivers/net/ethernet/aquantia/atlantic/aq_ring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c index f21de0c21e52..2c3cfceefd28 100644 --- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c +++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c @@ -538,6 +538,7 @@ static int __aq_ring_rx_clean(struct aq_ring_s *self, struct napi_struct *napi, bool is_ptp_ring = aq_ptp_ring(self->aq_nic, self); struct aq_ring_buff_s *buff_ = NULL; struct sk_buff *skb = NULL; + unsigned int frag_cnt = 0U; unsigned int next_ = 0U; unsigned int i = 0U; u16 hdr_len; @@ -546,7 +547,6 @@ static int __aq_ring_rx_clean(struct aq_ring_s *self, struct napi_struct *napi, continue; if (!buff->is_eop) { - unsigned int frag_cnt = 0U; buff_ = buff; do { bool is_rsc_completed = true; @@ -631,7 +631,7 @@ static int __aq_ring_rx_clean(struct aq_ring_s *self, struct napi_struct *napi, memcpy(__skb_put(skb, hdr_len), aq_buf_vaddr(&buff->rxdata), ALIGN(hdr_len, sizeof(long))); - if (buff->len - hdr_len > 0) { + if (buff->len - hdr_len > 0 && frag_cnt < MAX_SKB_FRAGS) { skb_add_rx_frag(skb, i++, buff->rxdata.page, buff->rxdata.pg_off + hdr_len, buff->len - hdr_len, -- 2.39.5