Apply ssh-keysign-pwn fix

This commit is contained in:
Koichiro Iwao 2026-05-18 05:40:22 +00:00
parent 527de344c7
commit 1b378ac076
2 changed files with 59 additions and 0 deletions

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@ -0,0 +1,55 @@
From: Andrew Lukoshko <alukoshko@almalinux.org>
Subject: [PATCH AlmaLinux 10] ptrace: require CAP_SYS_PTRACE when task has no mm
kABI-safe AlmaLinux backport of upstream commit 31e62c2ebbfd
("ptrace: slightly saner 'get_dumpable()' logic") posted at
https://github.com/torvalds/linux/commit/31e62c2ebbfdc3fe3dbdf5e02c92a9dc67087a3a
The upstream fix adds a 'user_dumpable:1' bit to task_struct and
caches the last dumpability in exit_mm() so __ptrace_may_access()
can require CAP_SYS_PTRACE when the target has no mm (e.g. kernel
threads or already-exited user tasks). That layout change to
task_struct breaks kABI on AlmaLinux 10 (the symtype
signature of struct task_struct is referenced by hundreds of
stablelist exports), so we cannot import the field/exit_mm hunks
as-is.
Take the minimal kABI-safe slice instead: when task->mm == NULL,
require CAP_SYS_PTRACE in init_user_ns unconditionally. This closes
the Qualys Security Advisory hole -- mm-less targets no longer pass
the dumpability check by default -- without touching task_struct or
exit.c. The only behavioural delta versus upstream is that a user
task that has already cleared its mm in exit_mm() (a dying/zombie
task) now also requires CAP_SYS_PTRACE to attach, instead of being
remembered as previously dumpable. Such targets are rarely ptraced
in practice.
Verified to apply with `patch -p1 -F0` (no offset, no fuzz, no rejects)
against kernel-6.12.0-124.56.1.el10_1.
Reported-by: Qualys Security Advisory <qsa@qualys.com>
Signed-off-by: Andrew Lukoshko <alukoshko@almalinux.org>
---
kernel/ptrace.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -339,8 +339,11 @@ static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
smp_rmb();
mm = task->mm;
- if (mm &&
- ((get_dumpable(mm) != SUID_DUMP_USER) &&
- !ptrace_has_cap(mm->user_ns, mode)))
- return -EPERM;
+ if (mm) {
+ if ((get_dumpable(mm) != SUID_DUMP_USER) &&
+ !ptrace_has_cap(mm->user_ns, mode))
+ return -EPERM;
+ } else if (!ptrace_has_cap(&init_user_ns, mode)) {
+ return -EPERM;
+ }
return security_ptrace_access_check(task, mode);
--
2.43.0

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@ -60,6 +60,8 @@ Patch1101: 1101-xfrm-esp-avoid-in-place-decrypt-shared-skb-frags.patch
Patch1102: 1102-rxrpc-linearize-paged-frags.patch
## CVE-2026-46300: Fragnesia
Patch1103: 1103-net-skbuff-propagate-shared-frag-marker.patch
## CVE-2026-46333: ssh-keysign-pwn
Patch1104: 1104-ptrace-require-cap-on-mm-less-task.patch
BuildRequires: kmod, patch, bash, coreutils, tar
BuildRequires: bzip2, xz, findutils, gzip, m4, perl, perl-Carp, make, diffutils, gawk
@ -243,6 +245,7 @@ glibc package.
%patch -P 1101 -p1
%patch -P 1102 -p1
%patch -P 1103 -p1
%patch -P 1104 -p1
perl -p -i -e "s/^EXTRAVERSION.*/EXTRAVERSION = -%{release}/" Makefile
perl -p -i -e "s/^CONFIG_LOCALVERSION=.*/CONFIG_LOCALVERSION=/" arch/%{Arch}/configs/bcm2711_defconfig
perl -p -i -e "s/^CONFIG_LOCALVERSION=.*/CONFIG_LOCALVERSION=/" arch/%{Arch}/configs/bcm2712_defconfig
@ -549,6 +552,7 @@ cp $(ls -1 /boot/config-kernel-*-*|sort -V|tail -1) /boot/config-kernel.inc
%changelog
* Thu May 14 2026 Koichiro Iwao <meta@almalinux.org> - 6.12.47-20250916.v8.6
- net: skbuff: propagate shared-frag marker through pskb_copy() {CVE-2026-46300}
- ptrace: require CAP_SYS_PTRACE when task has no mm {CVE-2026-46333}
* Fri May 08 2026 Koichiro Iwao <meta@almalinux.org> - 6.12.47-20250916.v8.5
- rxrpc: linearize incoming DATA packet when it has paged frags {CVE-2026-43500}