CVE-2021-47496
Assigner: Linux
Published: 2024-05-22T08:19:43.489Z
State: PUBLISHED
descriptions: value: 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=<negative error from crypto request>)
      tls_err_abort(.., err)
        sk->sk_err = err;

    [task]
    splice_from_pipe_feed
      ...
        tls_sw_do_sendpage
          if (sk->sk_err) {
            ret = -sk->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->len and
                        // sd->len, leading to huge buf->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: product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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
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
title: net/tls: Fix flipped sign in tls_err_abort() calls
x_generator: engine: bippy-d175d3acf727