CVE-2024-26766 IB/hfi1: Fix sdma.h tx->num_descs off-by-one error

2024-04-0317:00:48

Linux

github.com

linux kernel

vulnerability

error fix

sdma.h

off-by-one

overflow

crashes

sendmsg system call

panic

patch

stable

AI Score

6.9

Confidence

Low

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

In the Linux kernel, the following vulnerability has been resolved:

IB/hfi1: Fix sdma.h tx->num_descs off-by-one error

Unfortunately the commit fd8958efe877 introduced another error
causing the descs array to overflow. This reults in further crashes
easily reproducible by sendmsg system call.

[ 1080.836473] general protection fault, probably for non-canonical address 0x400300015528b00a: 0000 [#1] PREEMPT SMP PTI
[ 1080.869326] RIP: 0010:hfi1_ipoib_build_ib_tx_headers.constprop.0+0xe1/0x2b0 [hfi1]

[ 1080.974535] Call Trace:
[ 1080.976990] <TASK>
[ 1081.021929] hfi1_ipoib_send_dma_common+0x7a/0x2e0 [hfi1]
[ 1081.027364] hfi1_ipoib_send_dma_list+0x62/0x270 [hfi1]
[ 1081.032633] hfi1_ipoib_send+0x112/0x300 [hfi1]
[ 1081.042001] ipoib_start_xmit+0x2a9/0x2d0 [ib_ipoib]
[ 1081.046978] dev_hard_start_xmit+0xc4/0x210

[ 1081.148347] __sys_sendmsg+0x59/0xa0

crash> ipoib_txreq 0xffff9cfeba229f00
struct ipoib_txreq {
txreq = {
list = {
next = 0xffff9cfeba229f00,
prev = 0xffff9cfeba229f00
},
descp = 0xffff9cfeba229f40,
coalesce_buf = 0x0,
wait = 0xffff9cfea4e69a48,
complete = 0xffffffffc0fe0760 <hfi1_ipoib_sdma_complete>,
packet_len = 0x46d,
tlen = 0x0,
num_desc = 0x0,
desc_limit = 0x6,
next_descq_idx = 0x45c,
coalesce_idx = 0x0,
flags = 0x0,
descs = {{
qw = {0x8024000120dffb00, 0x4} # SDMA_DESC0_FIRST_DESC_FLAG (bit 63)
}, {
qw = { 0x3800014231b108, 0x4}
}, {
qw = { 0x310000e4ee0fcf0, 0x8}
}, {
qw = { 0x3000012e9f8000, 0x8}
}, {
qw = { 0x59000dfb9d0000, 0x8}
}, {
qw = { 0x78000e02e40000, 0x8}
}}
},
sdma_hdr = 0x400300015528b000, <<< invalid pointer in the tx request structure
sdma_status = 0x0, SDMA_DESC0_LAST_DESC_FLAG (bit 62)
complete = 0x0,
priv = 0x0,
txq = 0xffff9cfea4e69880,
skb = 0xffff9d099809f400
}

If an SDMA send consists of exactly 6 descriptors and requires dword
padding (in the 7th descriptor), the sdma_txreq descriptor array is not
properly expanded and the packet will overflow into the container
structure. This results in a panic when the send completion runs. The
exact panic varies depending on what elements of the container structure
get corrupted. The fix is to use the correct expression in
_pad_sdma_tx_descs() to test the need to expand the descriptor array.

With this patch the crashes are no longer reproducible and the machine is
stable.

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "d1c1ee052d25",
        "lessThan": "115b7f3bc1dc",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "40ac5cb6cbb0",
        "lessThan": "5833024a9856",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6cf8f3d690bb",
        "lessThan": "3f38d22e645e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "bd57756a7e43",
        "lessThan": "47ae64df23ed",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "eeaf35f4e3b3",
        "lessThan": "52dc9a7a573d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "fd8958efe877",
        "lessThan": "a2fef1d81bec",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "fd8958efe877",
        "lessThan": "9034a1bec35e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "fd8958efe877",
        "lessThan": "e6f57c688191",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/infiniband/hw/hfi1/sdma.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.3"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.3",
        "versionType": "custom"
      },
      {
        "status": "unaffected",
        "version": "4.19.308",
        "versionType": "custom",
        "lessThanOrEqual": "4.19.*"
      },
      {
        "status": "unaffected",
        "version": "5.4.270",
        "versionType": "custom",
        "lessThanOrEqual": "5.4.*"
      },
      {
        "status": "unaffected",
        "version": "5.10.211",
        "versionType": "custom",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.150",
        "versionType": "custom",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.80",
        "versionType": "custom",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.19",
        "versionType": "custom",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.7.7",
        "versionType": "custom",
        "lessThanOrEqual": "6.7.*"
      },
      {
        "status": "unaffected",
        "version": "6.8",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/infiniband/hw/hfi1/sdma.c"
    ],
    "defaultStatus": "affected"
  }
]