ghsa-xh88-4pfp-fhr6
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
igc: avoid returning frame twice in XDP_REDIRECT
When a frame can not be transmitted in XDP_REDIRECT (e.g. due to a full queue), it is necessary to free it by calling xdp_return_frame_rx_napi.
However, this is the responsibility of the caller of the ndo_xdp_xmit (see for example bq_xmit_all in kernel/bpf/devmap.c) and thus calling it inside igc_xdp_xmit (which is the ndo_xdp_xmit of the igc driver) as well will lead to memory corruption.
In fact, bq_xmit_all expects that it can return all frames after the last successfully transmitted one. Therefore, break for the first not transmitted frame, but do not call xdp_return_frame_rx_napi in igc_xdp_xmit. This is equally implemented in other Intel drivers such as the igb.
There are two alternatives to this that were rejected: 1. Return num_frames as all the frames would have been transmitted and release them inside igc_xdp_xmit. While it might work technically, it is not what the return value is meant to represent (i.e. the number of SUCCESSFULLY transmitted packets). 2. Rework kernel/bpf/devmap.c and all drivers to support non-consecutively dropped packets. Besides being complex, it likely has a negative performance impact without a significant gain since it is anyway unlikely that the next frame can be transmitted if the previous one was dropped.
The memory corruption can be reproduced with the following script which leads to a kernel panic after a few seconds. It basically generates more traffic than a i225 NIC can transmit and pushes it via XDP_REDIRECT from a virtual interface to the physical interface where frames get dropped.
#!/bin/bash
INTERFACE=enp4s0
INTERFACE_IDX=cat /sys/class/net/$INTERFACE/ifindex
sudo ip link add dev veth1 type veth peer name veth2 sudo ip link set up $INTERFACE sudo ip link set up veth1 sudo ip link set up veth2
cat << EOF > redirect.bpf.c
SEC("prog") int redirect(struct xdp_md *ctx) { return bpf_redirect($INTERFACE_IDX, 0); }
char _license[] SEC("license") = "GPL"; EOF clang -O2 -g -Wall -target bpf -c redirect.bpf.c -o redirect.bpf.o sudo ip link set veth2 xdp obj redirect.bpf.o
cat << EOF > pass.bpf.c
SEC("prog") int pass(struct xdp_md *ctx) { return XDP_PASS; }
char _license[] SEC("license") = "GPL"; EOF clang -O2 -g -Wall -target bpf -c pass.bpf.c -o pass.bpf.o sudo ip link set $INTERFACE xdp obj pass.bpf.o
cat << EOF > trafgen.cfg
{ / Ethernet Header / 0xe8, 0x6a, 0x64, 0x41, 0xbf, 0x46, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, const16(ETH_P_IP),
/* IPv4 Header */
0b01000101, 0, # IPv4 version, IHL, TOS
const16(1028), # IPv4 total length (UDP length + 20 bytes (IP header))
const16(2), # IPv4 ident
0b01000000, 0, # IPv4 flags, fragmentation off
64, # IPv4 TTL
17, # Protocol UDP
csumip(14, 33), # IPv4 checksum
/* UDP Header */
10, 0, 1, 1, # IP Src - adapt as needed
10, 0, 1, 2, # IP Dest - adapt as needed
const16(6666), # UDP Src Port
const16(6666), # UDP Dest Port
const16(1008), # UDP length (UDP header 8 bytes + payload length)
csumudp(14, 34), # UDP checksum
/* Payload */
fill('W', 1000),
} EOF
sudo trafgen -i trafgen.cfg -b3000MB -o veth1 --cpp
{
"affected": [],
"aliases": [
"CVE-2024-26853"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-04-17T11:15:08Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nigc: avoid returning frame twice in XDP_REDIRECT\n\nWhen a frame can not be transmitted in XDP_REDIRECT\n(e.g. due to a full queue), it is necessary to free\nit by calling xdp_return_frame_rx_napi.\n\nHowever, this is the responsibility of the caller of\nthe ndo_xdp_xmit (see for example bq_xmit_all in\nkernel/bpf/devmap.c) and thus calling it inside\nigc_xdp_xmit (which is the ndo_xdp_xmit of the igc\ndriver) as well will lead to memory corruption.\n\nIn fact, bq_xmit_all expects that it can return all\nframes after the last successfully transmitted one.\nTherefore, break for the first not transmitted frame,\nbut do not call xdp_return_frame_rx_napi in igc_xdp_xmit.\nThis is equally implemented in other Intel drivers\nsuch as the igb.\n\nThere are two alternatives to this that were rejected:\n1. Return num_frames as all the frames would have been\n transmitted and release them inside igc_xdp_xmit.\n While it might work technically, it is not what\n the return value is meant to represent (i.e. the\n number of SUCCESSFULLY transmitted packets).\n2. Rework kernel/bpf/devmap.c and all drivers to\n support non-consecutively dropped packets.\n Besides being complex, it likely has a negative\n performance impact without a significant gain\n since it is anyway unlikely that the next frame\n can be transmitted if the previous one was dropped.\n\nThe memory corruption can be reproduced with\nthe following script which leads to a kernel panic\nafter a few seconds. It basically generates more\ntraffic than a i225 NIC can transmit and pushes it\nvia XDP_REDIRECT from a virtual interface to the\nphysical interface where frames get dropped.\n\n #!/bin/bash\n INTERFACE=enp4s0\n INTERFACE_IDX=`cat /sys/class/net/$INTERFACE/ifindex`\n\n sudo ip link add dev veth1 type veth peer name veth2\n sudo ip link set up $INTERFACE\n sudo ip link set up veth1\n sudo ip link set up veth2\n\n cat \u003c\u003c EOF \u003e redirect.bpf.c\n\n SEC(\"prog\")\n int redirect(struct xdp_md *ctx)\n {\n return bpf_redirect($INTERFACE_IDX, 0);\n }\n\n char _license[] SEC(\"license\") = \"GPL\";\n EOF\n clang -O2 -g -Wall -target bpf -c redirect.bpf.c -o redirect.bpf.o\n sudo ip link set veth2 xdp obj redirect.bpf.o\n\n cat \u003c\u003c EOF \u003e pass.bpf.c\n\n SEC(\"prog\")\n int pass(struct xdp_md *ctx)\n {\n return XDP_PASS;\n }\n\n char _license[] SEC(\"license\") = \"GPL\";\n EOF\n clang -O2 -g -Wall -target bpf -c pass.bpf.c -o pass.bpf.o\n sudo ip link set $INTERFACE xdp obj pass.bpf.o\n\n cat \u003c\u003c EOF \u003e trafgen.cfg\n\n {\n /* Ethernet Header */\n 0xe8, 0x6a, 0x64, 0x41, 0xbf, 0x46,\n 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,\n const16(ETH_P_IP),\n\n /* IPv4 Header */\n 0b01000101, 0, # IPv4 version, IHL, TOS\n const16(1028), # IPv4 total length (UDP length + 20 bytes (IP header))\n const16(2), # IPv4 ident\n 0b01000000, 0, # IPv4 flags, fragmentation off\n 64, # IPv4 TTL\n 17, # Protocol UDP\n csumip(14, 33), # IPv4 checksum\n\n /* UDP Header */\n 10, 0, 1, 1, # IP Src - adapt as needed\n 10, 0, 1, 2, # IP Dest - adapt as needed\n const16(6666), # UDP Src Port\n const16(6666), # UDP Dest Port\n const16(1008), # UDP length (UDP header 8 bytes + payload length)\n csumudp(14, 34), # UDP checksum\n\n /* Payload */\n fill(\u0027W\u0027, 1000),\n }\n EOF\n\n sudo trafgen -i trafgen.cfg -b3000MB -o veth1 --cpp",
"id": "GHSA-xh88-4pfp-fhr6",
"modified": "2024-04-17T12:32:04Z",
"published": "2024-04-17T12:32:04Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26853"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1b3b8231386a572bac8cd5b6fd7e944b84f9bb1f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/63a3c1f3c9ecc654d851e7906d05334cd0c236e2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8df393af9e7e8dfd62e9c41dbaa4d2ff53bf794a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ef27f655b438bed4c83680e4f01e1cde2739854b"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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