Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Reject sleepable kprobe_multi programs at attach time kprobe.multi programs run in atomic/RCU context and cannot sleep. However, bpf_kprobe_multi_link_attach() did not validate whether the program being attached had the sleepable flag set, allowing sleepable helpers such as bpf_copy_from_user() to be invoked from a non-sleepable context. This causes a "sleeping function called from invalid context" splat: BUG: sleeping function called from invalid context at ./include/linux/uaccess.h:169 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1787, name: sudo preempt_count: 1, expected: 0 RCU nest depth: 2, expected: 0 Fix this by rejecting sleepable programs early in bpf_kprobe_multi_link_attach(), before any further processing.

Affected Products 8

References 3

• git.kernel.org https://git.kernel.org/stable/c/dc9a060d76c12b23c5f378ee115d5e5d03d8bbf3
  Patch
• git.kernel.org https://git.kernel.org/stable/c/eb7024bfcc5f68ed11ed9dd4891a3073c15f04a8
  Patch
• git.kernel.org https://git.kernel.org/stable/c/f952157e695fd434bdc05af63a703bb082a78717
  Patch

Remediation

• git.kernel.org https://git.kernel.org/stable/c/dc9a060d76c12b23c5f378ee115d5e5d03d8bbf3
  Patch
• git.kernel.org https://git.kernel.org/stable/c/eb7024bfcc5f68ed11ed9dd4891a3073c15f04a8
  Patch
• git.kernel.org https://git.kernel.org/stable/c/f952157e695fd434bdc05af63a703bb082a78717
  Patch