+ lib-zlib-unpoison-dfltcc-output-buffers.patch added to mm-unstable branch

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Andrew Morton

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Jun 19, 2024, 8:58:56 PMJun 19
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The patch titled
Subject: lib/zlib: unpoison DFLTCC output buffers
has been added to the -mm mm-unstable branch. Its filename is
lib-zlib-unpoison-dfltcc-output-buffers.patch

This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-zlib-unpoison-dfltcc-output-buffers.patch

This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Ilya Leoshkevich <i...@linux.ibm.com>
Subject: lib/zlib: unpoison DFLTCC output buffers
Date: Wed, 19 Jun 2024 17:43:54 +0200

The constraints of the DFLTCC inline assembly are not precise: they do not
communicate the size of the output buffers to the compiler, so it cannot
automatically instrument it.

Add the manual kmsan_unpoison_memory() calls for the output buffers. The
logic is the same as in [1].

[1] https://github.com/zlib-ng/zlib-ng/commit/1f5ddcc009ac3511e99fc88736a9e1a6381168c5

Link: https://lkml.kernel.org/r/20240619154530...@linux.ibm.com
Signed-off-by: Ilya Leoshkevich <i...@linux.ibm.com>
Reported-by: Alexander Gordeev <agor...@linux.ibm.com>
Reviewed-by: Alexander Potapenko <gli...@google.com>
Cc: Christian Borntraeger <bornt...@linux.ibm.com>
Cc: Christoph Lameter <c...@linux.com>
Cc: David Rientjes <rien...@google.com>
Cc: Dmitry Vyukov <dvy...@google.com>
Cc: Heiko Carstens <h...@linux.ibm.com>
Cc: Hyeonggon Yoo <42.h...@gmail.com>
Cc: Joonsoo Kim <iamjoon...@lge.com>
Cc: <kasa...@googlegroups.com>
Cc: Marco Elver <el...@google.com>
Cc: Mark Rutland <mark.r...@arm.com>
Cc: Masami Hiramatsu (Google) <mhir...@kernel.org>
Cc: Pekka Enberg <pen...@kernel.org>
Cc: Roman Gushchin <roman.g...@linux.dev>
Cc: Steven Rostedt (Google) <ros...@goodmis.org>
Cc: Sven Schnelle <sv...@linux.ibm.com>
Cc: Vasily Gorbik <g...@linux.ibm.com>
Cc: Vlastimil Babka <vba...@suse.cz>
Signed-off-by: Andrew Morton <ak...@linux-foundation.org>
---

lib/zlib_dfltcc/dfltcc.h | 1 +
lib/zlib_dfltcc/dfltcc_util.h | 28 ++++++++++++++++++++++++++++
2 files changed, 29 insertions(+)

--- a/lib/zlib_dfltcc/dfltcc.h~lib-zlib-unpoison-dfltcc-output-buffers
+++ a/lib/zlib_dfltcc/dfltcc.h
@@ -80,6 +80,7 @@ struct dfltcc_param_v0 {
uint8_t csb[1152];
};

+static_assert(offsetof(struct dfltcc_param_v0, csb) == 384);
static_assert(sizeof(struct dfltcc_param_v0) == 1536);

#define CVT_CRC32 0
--- a/lib/zlib_dfltcc/dfltcc_util.h~lib-zlib-unpoison-dfltcc-output-buffers
+++ a/lib/zlib_dfltcc/dfltcc_util.h
@@ -2,6 +2,8 @@
#ifndef DFLTCC_UTIL_H
#define DFLTCC_UTIL_H

+#include "dfltcc.h"
+#include <linux/kmsan-checks.h>
#include <linux/zutil.h>

/*
@@ -20,6 +22,7 @@ typedef enum {
#define DFLTCC_CMPR 2
#define DFLTCC_XPND 4
#define HBT_CIRCULAR (1 << 7)
+#define DFLTCC_FN_MASK ((1 << 7) - 1)
#define HB_BITS 15
#define HB_SIZE (1 << HB_BITS)

@@ -34,6 +37,7 @@ static inline dfltcc_cc dfltcc(
)
{
Byte *t2 = op1 ? *op1 : NULL;
+ unsigned char *orig_t2 = t2;
size_t t3 = len1 ? *len1 : 0;
const Byte *t4 = op2 ? *op2 : NULL;
size_t t5 = len2 ? *len2 : 0;
@@ -59,6 +63,30 @@ static inline dfltcc_cc dfltcc(
: "cc", "memory");
t2 = r2; t3 = r3; t4 = r4; t5 = r5;

+ /*
+ * Unpoison the parameter block and the output buffer.
+ * This is a no-op in non-KMSAN builds.
+ */
+ switch (fn & DFLTCC_FN_MASK) {
+ case DFLTCC_QAF:
+ kmsan_unpoison_memory(param, sizeof(struct dfltcc_qaf_param));
+ break;
+ case DFLTCC_GDHT:
+ kmsan_unpoison_memory(param, offsetof(struct dfltcc_param_v0, csb));
+ break;
+ case DFLTCC_CMPR:
+ kmsan_unpoison_memory(param, sizeof(struct dfltcc_param_v0));
+ kmsan_unpoison_memory(
+ orig_t2,
+ t2 - orig_t2 +
+ (((struct dfltcc_param_v0 *)param)->sbb == 0 ? 0 : 1));
+ break;
+ case DFLTCC_XPND:
+ kmsan_unpoison_memory(param, sizeof(struct dfltcc_param_v0));
+ kmsan_unpoison_memory(orig_t2, t2 - orig_t2);
+ break;
+ }
+
if (op1)
*op1 = t2;
if (len1)
_

Patches currently in -mm which might be from i...@linux.ibm.com are

ftrace-unpoison-ftrace_regs-in-ftrace_ops_list_func.patch
kmsan-make-the-tests-compatible-with-kmsanpanic=1.patch
kmsan-disable-kmsan-when-deferred_struct_page_init-is-enabled.patch
kmsan-increase-the-maximum-store-size-to-4096.patch
kmsan-fix-is_bad_asm_addr-on-arches-with-overlapping-address-spaces.patch
kmsan-fix-kmsan_copy_to_user-on-arches-with-overlapping-address-spaces.patch
kmsan-remove-a-useless-assignment-from-kmsan_vmap_pages_range_noflush.patch
kmsan-remove-an-x86-specific-include-from-kmsanh.patch
kmsan-expose-kmsan_get_metadata.patch
kmsan-export-panic_on_kmsan.patch
kmsan-allow-disabling-kmsan-checks-for-the-current-task.patch
kmsan-introduce-memset_no_sanitize_memory.patch
kmsan-support-slab_poison.patch
kmsan-use-align_down-in-kmsan_get_metadata.patch
kmsan-do-not-round-up-pg_data_t-size.patch
mm-slub-let-kmsan-access-metadata.patch
mm-slub-disable-kmsan-when-checking-the-padding-bytes.patch
mm-kfence-disable-kmsan-when-checking-the-canary.patch
lib-zlib-unpoison-dfltcc-output-buffers.patch
kmsan-accept-ranges-starting-with-0-on-s390.patch
s390-boot-turn-off-kmsan.patch
s390-use-a-larger-stack-for-kmsan.patch
s390-boot-add-the-kmsan-runtime-stub.patch
s390-checksum-add-a-kmsan-check.patch
s390-cpacf-unpoison-the-results-of-cpacf_trng.patch
s390-cpumf-unpoison-stcctm-output-buffer.patch
s390-diag-unpoison-diag224-output-buffer.patch
s390-ftrace-unpoison-ftrace_regs-in-kprobe_ftrace_handler.patch
s390-irqflags-do-not-instrument-arch_local_irq_-with-kmsan.patch
s390-mm-define-kmsan-metadata-for-vmalloc-and-modules.patch
s390-string-add-kmsan-support.patch
s390-traps-unpoison-the-kernel_stack_overflows-pt_regs.patch
s390-uaccess-add-kmsan-support-to-put_user-and-get_user.patch
s390-uaccess-add-the-missing-linux-instrumentedh-include.patch
s390-unwind-disable-kmsan-checks.patch
s390-kmsan-implement-the-architecture-specific-functions.patch
kmsan-enable-on-s390.patch

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