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A single fix for the generic entry code: 

THe trace_sys_enter() tracepoint can modify the syscall number via
   kprobes or BPF in pt_regs, but that requires that the syscall number is
   re-evaluted from pt_regs after the tracepoint.
 
   A seccomp fix in that area removed the re-evaluation so the change does
   not take effect as the code just uses the locally cached number.
 
   Restore the original behaviour by re-evaluating the syscall number after
   the tracepoint.
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Merge tag 'core-entry-2024-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core entry fix from Thomas Gleixner:
 "A single fix for the generic entry code:

  The trace_sys_enter() tracepoint can modify the syscall number via
  kprobes or BPF in pt_regs, but that requires that the syscall number
  is re-evaluted from pt_regs after the tracepoint.

  A seccomp fix in that area removed the re-evaluation so the change
  does not take effect as the code just uses the locally cached number.

  Restore the original behaviour by re-evaluating the syscall number
  after the tracepoint"

* tag 'core-entry-2024-03-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  entry: Respect changes to system call number by trace_sys_enter()
This commit is contained in:
Linus Torvalds 2024-03-23 14:17:37 -07:00
parent 484193fecd fb13b11d53
commit 976b029d06
1 changed files with 7 additions and 1 deletions
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8
kernel/entry/common.c
View File

@ -57,8 +57,14 @@ long syscall_trace_enter(struct pt_regs *regs, long syscall,
/* Either of the above might have changed the syscall number */
syscall = syscall_get_nr(current, regs);
if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT))
if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT)) {
trace_sys_enter(regs, syscall);
/*
* Probes or BPF hooks in the tracepoint may have changed the
* system call number as well.
*/
syscall = syscall_get_nr(current, regs);
}
syscall_enter_audit(regs, syscall);