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authorHelge Deller <deller@gmx.de>2023-11-18 19:33:35 +0100
committerHelge Deller <deller@gmx.de>2023-11-18 19:35:31 +0100
commit793838138c157d4c49f4fb744b170747e3dabf58 (patch)
tree4fe9275c0bbcfd3042b70b1880c9e894aeaa65bf /kernel
parent6ad6e15a9c46b8f0932cd99724f26f3db4db1cdf (diff)
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@gmx.de> Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Sam James <sam@gentoo.org> Closes: https://github.com/systemd/systemd/issues/29775 Tested-by: Sam James <sam@gentoo.org> Link: https://lore.kernel.org/all/875y2jro9a.fsf@gentoo.org/ Cc: <stable@vger.kernel.org> # v6.3+
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sys.c4
1 files changed, 4 insertions, 0 deletions
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 */