Zev Weiss d5aad4c2ca prctl: generalize PR_SET_MDWE support check to be per-arch ... Patch series "ARM: prctl: Reject PR_SET_MDWE where not supported". I noticed after a recent kernel update that my ARM926 system started segfaulting on any execve() after calling prctl(PR_SET_MDWE). After some investigation it appears that ARMv5 is incapable of providing the appropriate protections for MDWE, since any readable memory is also implicitly executable. The prctl_set_mdwe() function already had some special-case logic added disabling it on PARISC (commit 793838138c, "prctl: Disable prctl(PR_SET_MDWE) on parisc"); this patch series (1) generalizes that check to use an arch_*() function, and (2) adds a corresponding override for ARM to disable MDWE on pre-ARMv6 CPUs. With the series applied, prctl(PR_SET_MDWE) is rejected on ARMv5 and subsequent execve() calls (as well as mmap(PROT_READ|PROT_WRITE)) can succeed instead of unconditionally failing; on ARMv6 the prctl works as it did previously. [0] https://lore.kernel.org/all/2023112456-linked-nape-bf19@gregkh/ This patch (of 2): There exist systems other than PARISC where MDWE may not be feasible to support; rather than cluttering up the generic code with additional arch-specific logic let's add a generic function for checking MDWE support and allow each arch to override it as needed. Link: https://lkml.kernel.org/r/20240227013546.15769-4-zev@bewilderbeest.net Link: https://lkml.kernel.org/r/20240227013546.15769-5-zev@bewilderbeest.net Signed-off-by: Zev Weiss <zev@bewilderbeest.net> Acked-by: Helge Deller <deller@gmx.de> [parisc] Cc: Borislav Petkov <bp@alien8.de> Cc: David Hildenbrand <david@redhat.com> Cc: Florent Revest <revest@chromium.org> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Kees Cook <keescook@chromium.org> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ondrej Mosnacek <omosnace@redhat.com> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com> Cc: Russell King (Oracle) <linux@armlinux.org.uk> Cc: Sam James <sam@gentoo.org> Cc: Stefan Roesch <shr@devkernel.io> Cc: Yang Shi <yang@os.amperecomputing.com> Cc: Yin Fengwei <fengwei.yin@intel.com> Cc: <stable@vger.kernel.org> [6.3+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>		2024-03-26 11:07:22 -07:00
..
acpi	ACPI updates for 6.9-rc1	2024-03-13 11:54:05 -07:00
asm-generic	RISC-V Patches for the 6.9 Merge Window	2024-03-22 10:41:13 -07:00
clocksource
crypto	This update includes the following changes:	2024-03-15 14:46:54 -07:00
drm	drm fixes for 6.9-rc1	2024-03-21 19:04:31 -07:00
dt-bindings	Char/Misc and other driver subsystem updates for 6.9-rc1	2024-03-21 13:21:31 -07:00
keys
kunit
kvm
linux	prctl: generalize PR_SET_MDWE support check to be per-arch	2024-03-26 11:07:22 -07:00
math-emu
media	media updates for v6.9-rc1	2024-03-15 11:36:54 -07:00
memory
misc
net	Including fixes from CAN, netfilter, wireguard and IPsec.	2024-03-21 14:50:39 -07:00
pcmcia
ras	PCI/AER: Generalize TLP Header Log reading	2024-03-08 15:26:46 -06:00
rdma
rv
scsi	SCSI misc on 20240322	2024-03-22 13:31:07 -07:00
soc	Char/Misc and other driver subsystem updates for 6.9-rc1	2024-03-21 13:21:31 -07:00
sound	sound updates for 6.9-rc1	2024-03-14 11:10:43 -07:00
target
trace	tracing: Just use strcmp() for testing __string() and __assign_str() match	2024-03-19 11:23:30 -07:00
uapi	TTY/Serial driver update for 6.9-rc1	2024-03-21 12:44:10 -07:00
ufs
vdso
video
xen