protect the fetch of ->fd[fd] in do_dup2() from mispredictions

Summary

In the Linux kernel, the following vulnerability has been resolved: protect the fetch of ->fd[fd] in do_dup2() from mispredictions both callers have verified that fd is not greater than ->max_fds; however, misprediction might end up with tofree = fdt->fd[fd]; being speculatively executed. That's wrong for the same reasons why it's wrong in close_fd()/file_close_fd_locked(); the same solution applies - array_index_nospec(fd, fdt->max_fds) could differ from fd only in case of speculative execution on mispredicted path.

Timeline

1. Aug 17, 2024, 8:54 AM UTCCVE published
2. Sep 10, 2024, 4:12 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Oct 15, 2026, 12:48 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 8280d16172243702ed43432f826ca6130edb4086 · fixed in ed42e8ff509d2a61c6642d1825032072dab79f26; From 8280d16172243702ed43432f826ca6130edb4086 · fixed in 41a6c31df77bd8e050136b0a200b537da9e1084a; From 8280d16172243702ed43432f826ca6130edb4086 · fixed in 08775b3d6ed117cf4518754ec7300ee42b6a5368; From 8280d16172243702ed43432f826ca6130edb4086 · fixed in 3f480493550b6a23d3a65d095d6569d4a7f56a0f; From 8280d16172243702ed43432f826ca6130edb4086 · fixed in 5db999fff545b924b24c9afd368ef5c17279b176; From 8280d16172243702ed43432f826ca6130edb4086 · fixed in da72e783afd27d9f487836b2e6738146c0edd149; From 8280d16172243702ed43432f826ca6130edb4086 · fixed in 1171ceccabfd596ca370c5d2cbb47d110c3f2fe1; From 8280d16172243702ed43432f826ca6130edb4086 · fixed in 8aa37bde1a7b645816cda8b80df4753ecf172bf1

• Linux Linux

  3.7

• KernelLinux

  From 3.7.0 · fixed in 4.19.320; From 4.20.0 · fixed in 5.4.282; From 5.5.0 · fixed in 5.10.224; From 5.11.0 · fixed in 5.15.165; From 5.16.0 · fixed in 6.1.104; From 6.2.0 · fixed in 6.6.45; From 6.7.0 · fixed in 6.10.4

References 8