CVE-2021-47496

2024-05-2209:15:11

416baaa9-dc9f-4396-8d5f-8c081fb06d67

web.nvd.nist.gov

linux kernel

tls

vulnerability

sign error

memory corruption

error code

security

6.9 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

15.5%

JSON

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

net/tls: Fix flipped sign in tls_err_abort() calls

sk->sk_err appears to expect a positive value, a convention that ktls
doesn’t always follow and that leads to memory corruption in other code.
For instance,

[kworker]
tls_encrypt_done(..., err=&lt;negative error from crypto request&gt;)
  tls_err_abort(.., err)
    sk-&gt;sk_err = err;

[task]
splice_from_pipe_feed
  ...
    tls_sw_do_sendpage
      if (sk-&gt;sk_err) {
        ret = -sk-&gt;sk_err;  // ret is positive

splice_from_pipe_feed (continued)
  ret = actor(...)  // ret is still positive and interpreted as bytes
                    // written, resulting in underflow of buf-&gt;len and
                    // sd-&gt;len, leading to huge buf-&gt;offset and bogus
                    // addresses computed in later calls to actor()

Fix all tls_err_abort() callers to pass a negative error code
consistently and centralize the error-prone sign flip there, throwing in
a warning to catch future misuse and uninlining the function so it
really does only warn once.

Affected configurations

Vulners

Node

linuxlinux_kernelRange4.17–5.4.157

linuxlinux_kernelRange5.5.0–5.10.77

linuxlinux_kernelRange5.11.0–5.14.16

linuxlinux_kernelRange5.15.0≥

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "include/net/tls.h",
      "net/tls/tls_sw.c"
    ],
    "versions": [
      {
        "version": "c46234ebb4d1",
        "lessThan": "e0cfd5159f31",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c46234ebb4d1",
        "lessThan": "f3dec7e7ace3",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c46234ebb4d1",
        "lessThan": "e41473543f75",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c46234ebb4d1",
        "lessThan": "da353fac65fe",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "include/net/tls.h",
      "net/tls/tls_sw.c"
    ],
    "versions": [
      {
        "version": "4.17",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "4.17",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.4.157",
        "lessThanOrEqual": "5.4.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.77",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.14.16",
        "lessThanOrEqual": "5.14.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]