On 11/24/23 12:35, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
The patch below does not apply to the 6.5-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.5.y
git checkout FETCH_HEAD
git cherry-pick -x 793838138c157d4c49f4fb744b170747e3dabf58
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023112456-linked-nape-bf19@gregkh' --subject-prefix 'PATCH 6.5.y' HEAD^..
Possible dependencies:
793838138c15 ("prctl: Disable prctl(PR_SET_MDWE) on parisc")
24e41bf8a6b4 ("mm: add a NO_INHERIT flag to the PR_SET_MDWE prctl")
0da668333fb0 ("mm: make PR_MDWE_REFUSE_EXEC_GAIN an unsigned long")
Greg, I think the most clean solution is that you pull in this patch:
commit 24e41bf8a6b424c76c5902fb999e9eca61bdf83d
Author: Florent Revest <revest@xxxxxxxxxxxx>
Date: Mon Aug 28 17:08:57 2023 +0200
mm: add a NO_INHERIT flag to the PR_SET_MDWE prctl
as well into 6.5-stable and 6.6-stable prior to applying my patch.
Florent, Kees and Catalin, do you see any issues if this patch
("mm: add a NO_INHERIT flag to the PR_SET_MDWE prctl") is backported
to 6.5 and 6.6 too?
If yes, I'm happy to just send the trivial backport of my patch below...
Helge
------------------ original commit in Linus's tree ------------------
From 793838138c157d4c49f4fb744b170747e3dabf58 Mon Sep 17 00:00:00 2001
From: Helge Deller <deller@xxxxxx>
Date: Sat, 18 Nov 2023 19:33:35 +0100
Subject: [PATCH] prctl: Disable prctl(PR_SET_MDWE) on parisc
systemd-254 tries to use prctl(PR_SET_MDWE) for it's MemoryDenyWriteExecute
functionality, but fails on parisc which still needs executable stacks in
certain combinations of gcc/glibc/kernel.
Disable prctl(PR_SET_MDWE) by returning -EINVAL for now on parisc, until
userspace has catched up.
Signed-off-by: Helge Deller <deller@xxxxxx>
Co-developed-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Reported-by: Sam James <sam@xxxxxxxxxx>
Closes: https://github.com/systemd/systemd/issues/29775
Tested-by: Sam James <sam@xxxxxxxxxx>
Link: https://lore.kernel.org/all/875y2jro9a.fsf@xxxxxxxxxx/
Cc: <stable@xxxxxxxxxxxxxxx> # v6.3+
diff --git a/kernel/sys.c b/kernel/sys.c
index 420d9cb9cc8e..e219fcfa112d 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2394,6 +2394,10 @@ static inline int prctl_set_mdwe(unsigned long bits, unsigned long arg3,
if (bits & PR_MDWE_NO_INHERIT && !(bits & PR_MDWE_REFUSE_EXEC_GAIN))
return -EINVAL;
+ /* PARISC cannot allow mdwe as it needs writable stacks */
+ if (IS_ENABLED(CONFIG_PARISC))
+ return -EINVAL;
+
current_bits = get_current_mdwe();
if (current_bits && current_bits != bits)
return -EPERM; /* Cannot unset the flags */
