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prctl: move PR_GET_AUXV out of PR_MCE_KILL 

Somehow PR_GET_AUXV got added into PR_MCE_KILL's switch when the patch was
applied [1].

Thus move it out of the switch, to the place the patch added it.

In the recently released v6.4 kernel some user could, in principle, be
already using this feature by mapping the right page and passing the
PR_GET_AUXV constant as a pointer:

    prctl(PR_MCE_KILL, PR_GET_AUXV, ...)

So this does change the behavior for users.  We could keep the bug since
the other subcases in PR_MCE_KILL (PR_MCE_KILL_CLEAR and PR_MCE_KILL_SET)
do not overlap.

However, v6.4 may be recent enough (2 weeks old) that moving the lines
(rather than just adding a new case) does not break anybody?  Moreover,
the documentation in man-pages was just committed today [2].

Link: https://lkml.kernel.org/r/20230708233344.361854-1-ojeda@kernel.org
Fixes: ddc65971bb ("prctl: add PR_GET_AUXV to copy auxv to userspace")
Link: https://lore.kernel.org/all/d81864a7f7f43bca6afa2a09fc2e850e4050ab42.1680611394.git.josh@joshtriplett.org/ [1]
Link: https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit/?id=8cf0c06bfd3c2b219b044d4151c96f0da50af9ad [2]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Miguel Ojeda 2023-07-09 01:33:44 +02:00 committed by Andrew Morton
parent f13be0ad53
commit 636e348353
1 changed files with 5 additions and 5 deletions
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10
kernel/sys.c
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@ -2535,11 +2535,6 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
else
return -EINVAL;
break;
case PR_GET_AUXV:
if (arg4 || arg5)
return -EINVAL;
error = prctl_get_auxv((void __user *)arg2, arg3);
break;
default:
return -EINVAL;
}
@ -2694,6 +2689,11 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
case PR_SET_VMA:
error = prctl_set_vma(arg2, arg3, arg4, arg5);
break;
case PR_GET_AUXV:
if (arg4 || arg5)
return -EINVAL;
error = prctl_get_auxv((void __user *)arg2, arg3);
break;
#ifdef CONFIG_KSM
case PR_SET_MEMORY_MERGE:
if (arg3 || arg4 || arg5)