* FAILED: patch "[PATCH] randstruct: gcc-plugin: Fix attribute addition" failed to apply to 5.15-stable tree
@ 2025-06-05 8:43 gregkh
2025-09-05 15:52 ` [PATCH 5.15.y 1/2] randstruct: gcc-plugin: Remove bogus void member Sasha Levin
0 siblings, 1 reply; 3+ messages in thread
From: gregkh @ 2025-06-05 8:43 UTC (permalink / raw)
To: kees, ingo, thiago.bauermann; +Cc: stable
The patch below does not apply to the 5.15-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@vger.kernel.org>.
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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x f39f18f3c3531aa802b58a20d39d96e82eb96c14
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025060527-upwind-coveting-bcba@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From f39f18f3c3531aa802b58a20d39d96e82eb96c14 Mon Sep 17 00:00:00 2001
From: Kees Cook <kees@kernel.org>
Date: Fri, 30 May 2025 15:18:28 -0700
Subject: [PATCH] randstruct: gcc-plugin: Fix attribute addition
Based on changes in the 2021 public version of the randstruct
out-of-tree GCC plugin[1], more carefully update the attributes on
resulting decls, to avoid tripping checks in GCC 15's
comptypes_check_enum_int() when it has been configured with
"--enable-checking=misc":
arch/arm64/kernel/kexec_image.c:132:14: internal compiler error: in comptypes_check_enum_int, at c/c-typeck.cc:1519
132 | const struct kexec_file_ops kexec_image_ops = {
| ^~~~~~~~~~~~~~
internal_error(char const*, ...), at gcc/gcc/diagnostic-global-context.cc:517
fancy_abort(char const*, int, char const*), at gcc/gcc/diagnostic.cc:1803
comptypes_check_enum_int(tree_node*, tree_node*, bool*), at gcc/gcc/c/c-typeck.cc:1519
...
Link: https://archive.org/download/grsecurity/grsecurity-3.1-5.10.41-202105280954.patch.gz [1]
Reported-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Closes: https://github.com/KSPP/linux/issues/367
Closes: https://lore.kernel.org/lkml/20250530000646.104457-1-thiago.bauermann@linaro.org/
Reported-by: Ingo Saitz <ingo@hannover.ccc.de>
Closes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1104745
Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin")
Tested-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Link: https://lore.kernel.org/r/20250530221824.work.623-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
diff --git a/scripts/gcc-plugins/gcc-common.h b/scripts/gcc-plugins/gcc-common.h
index 3222c1070444..ef12c8f929ed 100644
--- a/scripts/gcc-plugins/gcc-common.h
+++ b/scripts/gcc-plugins/gcc-common.h
@@ -123,6 +123,38 @@ static inline tree build_const_char_string(int len, const char *str)
return cstr;
}
+static inline void __add_type_attr(tree type, const char *attr, tree args)
+{
+ tree oldattr;
+
+ if (type == NULL_TREE)
+ return;
+ oldattr = lookup_attribute(attr, TYPE_ATTRIBUTES(type));
+ if (oldattr != NULL_TREE) {
+ gcc_assert(TREE_VALUE(oldattr) == args || TREE_VALUE(TREE_VALUE(oldattr)) == TREE_VALUE(args));
+ return;
+ }
+
+ TYPE_ATTRIBUTES(type) = copy_list(TYPE_ATTRIBUTES(type));
+ TYPE_ATTRIBUTES(type) = tree_cons(get_identifier(attr), args, TYPE_ATTRIBUTES(type));
+}
+
+static inline void add_type_attr(tree type, const char *attr, tree args)
+{
+ tree main_variant = TYPE_MAIN_VARIANT(type);
+
+ __add_type_attr(TYPE_CANONICAL(type), attr, args);
+ __add_type_attr(TYPE_CANONICAL(main_variant), attr, args);
+ __add_type_attr(main_variant, attr, args);
+
+ for (type = TYPE_NEXT_VARIANT(main_variant); type; type = TYPE_NEXT_VARIANT(type)) {
+ if (!lookup_attribute(attr, TYPE_ATTRIBUTES(type)))
+ TYPE_ATTRIBUTES(type) = TYPE_ATTRIBUTES(main_variant);
+
+ __add_type_attr(TYPE_CANONICAL(type), attr, args);
+ }
+}
+
#define PASS_INFO(NAME, REF, ID, POS) \
struct register_pass_info NAME##_pass_info = { \
.pass = make_##NAME##_pass(), \
diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
index 971a1908a8cc..ff65a4f87f24 100644
--- a/scripts/gcc-plugins/randomize_layout_plugin.c
+++ b/scripts/gcc-plugins/randomize_layout_plugin.c
@@ -73,6 +73,9 @@ static tree handle_randomize_layout_attr(tree *node, tree name, tree args, int f
if (TYPE_P(*node)) {
type = *node;
+ } else if (TREE_CODE(*node) == FIELD_DECL) {
+ *no_add_attrs = false;
+ return NULL_TREE;
} else {
gcc_assert(TREE_CODE(*node) == TYPE_DECL);
type = TREE_TYPE(*node);
@@ -348,15 +351,14 @@ static int relayout_struct(tree type)
TREE_CHAIN(newtree[i]) = newtree[i+1];
TREE_CHAIN(newtree[num_fields - 1]) = NULL_TREE;
+ add_type_attr(type, "randomize_performed", NULL_TREE);
+ add_type_attr(type, "designated_init", NULL_TREE);
+ if (has_flexarray)
+ add_type_attr(type, "has_flexarray", NULL_TREE);
+
main_variant = TYPE_MAIN_VARIANT(type);
- for (variant = main_variant; variant; variant = TYPE_NEXT_VARIANT(variant)) {
+ for (variant = main_variant; variant; variant = TYPE_NEXT_VARIANT(variant))
TYPE_FIELDS(variant) = newtree[0];
- TYPE_ATTRIBUTES(variant) = copy_list(TYPE_ATTRIBUTES(variant));
- TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("randomize_performed"), NULL_TREE, TYPE_ATTRIBUTES(variant));
- TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("designated_init"), NULL_TREE, TYPE_ATTRIBUTES(variant));
- if (has_flexarray)
- TYPE_ATTRIBUTES(type) = tree_cons(get_identifier("has_flexarray"), NULL_TREE, TYPE_ATTRIBUTES(type));
- }
/*
* force a re-layout of the main variant
@@ -424,10 +426,8 @@ static void randomize_type(tree type)
if (lookup_attribute("randomize_layout", TYPE_ATTRIBUTES(TYPE_MAIN_VARIANT(type))) || is_pure_ops_struct(type))
relayout_struct(type);
- for (variant = TYPE_MAIN_VARIANT(type); variant; variant = TYPE_NEXT_VARIANT(variant)) {
- TYPE_ATTRIBUTES(type) = copy_list(TYPE_ATTRIBUTES(type));
- TYPE_ATTRIBUTES(type) = tree_cons(get_identifier("randomize_considered"), NULL_TREE, TYPE_ATTRIBUTES(type));
- }
+ add_type_attr(type, "randomize_considered", NULL_TREE);
+
#ifdef __DEBUG_PLUGIN
fprintf(stderr, "Marking randomize_considered on struct %s\n", ORIG_TYPE_NAME(type));
#ifdef __DEBUG_VERBOSE
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH 5.15.y 1/2] randstruct: gcc-plugin: Remove bogus void member
2025-06-05 8:43 FAILED: patch "[PATCH] randstruct: gcc-plugin: Fix attribute addition" failed to apply to 5.15-stable tree gregkh
@ 2025-09-05 15:52 ` Sasha Levin
2025-09-05 15:52 ` [PATCH 5.15.y 2/2] randstruct: gcc-plugin: Fix attribute addition Sasha Levin
0 siblings, 1 reply; 3+ messages in thread
From: Sasha Levin @ 2025-09-05 15:52 UTC (permalink / raw)
To: stable; +Cc: Kees Cook, Dr. David Alan Gilbert, Mark Brown, WangYuli,
Sasha Levin
From: Kees Cook <kees@kernel.org>
[ Upstream commit e136a4062174a9a8d1c1447ca040ea81accfa6a8 ]
When building the randomized replacement tree of struct members, the
randstruct GCC plugin would insert, as the first member, a 0-sized void
member. This appears as though it was done to catch non-designated
("unnamed") static initializers, which wouldn't be stable since they
depend on the original struct layout order.
This was accomplished by having the side-effect of the "void member"
tripping an assert in GCC internals (count_type_elements) if the member
list ever needed to be counted (e.g. for figuring out the order of members
during a non-designated initialization), which would catch impossible type
(void) in the struct:
security/landlock/fs.c: In function ‘hook_file_ioctl_common’:
security/landlock/fs.c:1745:61: internal compiler error: in count_type_elements, at expr.cc:7075
1745 | .u.op = &(struct lsm_ioctlop_audit) {
| ^
static HOST_WIDE_INT
count_type_elements (const_tree type, bool for_ctor_p)
{
switch (TREE_CODE (type))
...
case VOID_TYPE:
default:
gcc_unreachable ();
}
}
However this is a redundant safety measure since randstruct uses the
__designated_initializer attribute both internally and within the
__randomized_layout attribute macro so that this would be enforced
by the compiler directly even when randstruct was not enabled (via
-Wdesignated-init).
A recent change in Landlock ended up tripping the same member counting
routine when using a full-struct copy initializer as part of an anonymous
initializer. This, however, is a false positive as the initializer is
copying between identical structs (and hence identical layouts). The
"path" member is "struct path", a randomized struct, and is being copied
to from another "struct path", the "f_path" member:
landlock_log_denial(landlock_cred(file->f_cred), &(struct landlock_request) {
.type = LANDLOCK_REQUEST_FS_ACCESS,
.audit = {
.type = LSM_AUDIT_DATA_IOCTL_OP,
.u.op = &(struct lsm_ioctlop_audit) {
.path = file->f_path,
.cmd = cmd,
},
},
...
As can be seen with the coming randstruct KUnit test, there appears to
be no behavioral problems with this kind of initialization when the void
member is removed from the randstruct GCC plugin, so remove it.
Reported-by: "Dr. David Alan Gilbert" <linux@treblig.org>
Closes: https://lore.kernel.org/lkml/Z_PRaKx7q70MKgCA@gallifrey/
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/lkml/20250407-kbuild-disable-gcc-plugins-v1-1-5d46ae583f5e@kernel.org/
Reported-by: WangYuli <wangyuli@uniontech.com>
Closes: https://lore.kernel.org/lkml/337D5D4887277B27+3c677db3-a8b9-47f0-93a4-7809355f1381@uniontech.com/
Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin")
Signed-off-by: Kees Cook <kees@kernel.org>
Stable-dep-of: f39f18f3c353 ("randstruct: gcc-plugin: Fix attribute addition")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
scripts/gcc-plugins/randomize_layout_plugin.c | 18 +-----------------
1 file changed, 1 insertion(+), 17 deletions(-)
diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
index 60e9359a71a50..a8595df5fb6e8 100644
--- a/scripts/gcc-plugins/randomize_layout_plugin.c
+++ b/scripts/gcc-plugins/randomize_layout_plugin.c
@@ -377,29 +377,13 @@ static int relayout_struct(tree type)
shuffle(type, (tree *)newtree, shuffle_length);
- /*
- * set up a bogus anonymous struct field designed to error out on unnamed struct initializers
- * as gcc provides no other way to detect such code
- */
- list = make_node(FIELD_DECL);
- TREE_CHAIN(list) = newtree[0];
- TREE_TYPE(list) = void_type_node;
- DECL_SIZE(list) = bitsize_zero_node;
- DECL_NONADDRESSABLE_P(list) = 1;
- DECL_FIELD_BIT_OFFSET(list) = bitsize_zero_node;
- DECL_SIZE_UNIT(list) = size_zero_node;
- DECL_FIELD_OFFSET(list) = size_zero_node;
- DECL_CONTEXT(list) = type;
- // to satisfy the constify plugin
- TREE_READONLY(list) = 1;
-
for (i = 0; i < num_fields - 1; i++)
TREE_CHAIN(newtree[i]) = newtree[i+1];
TREE_CHAIN(newtree[num_fields - 1]) = NULL_TREE;
main_variant = TYPE_MAIN_VARIANT(type);
for (variant = main_variant; variant; variant = TYPE_NEXT_VARIANT(variant)) {
- TYPE_FIELDS(variant) = list;
+ TYPE_FIELDS(variant) = newtree[0];
TYPE_ATTRIBUTES(variant) = copy_list(TYPE_ATTRIBUTES(variant));
TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("randomize_performed"), NULL_TREE, TYPE_ATTRIBUTES(variant));
TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("designated_init"), NULL_TREE, TYPE_ATTRIBUTES(variant));
--
2.50.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH 5.15.y 2/2] randstruct: gcc-plugin: Fix attribute addition
2025-09-05 15:52 ` [PATCH 5.15.y 1/2] randstruct: gcc-plugin: Remove bogus void member Sasha Levin
@ 2025-09-05 15:52 ` Sasha Levin
0 siblings, 0 replies; 3+ messages in thread
From: Sasha Levin @ 2025-09-05 15:52 UTC (permalink / raw)
To: stable; +Cc: Kees Cook, Thiago Jung Bauermann, Ingo Saitz, Sasha Levin
From: Kees Cook <kees@kernel.org>
[ Upstream commit f39f18f3c3531aa802b58a20d39d96e82eb96c14 ]
Based on changes in the 2021 public version of the randstruct
out-of-tree GCC plugin[1], more carefully update the attributes on
resulting decls, to avoid tripping checks in GCC 15's
comptypes_check_enum_int() when it has been configured with
"--enable-checking=misc":
arch/arm64/kernel/kexec_image.c:132:14: internal compiler error: in comptypes_check_enum_int, at c/c-typeck.cc:1519
132 | const struct kexec_file_ops kexec_image_ops = {
| ^~~~~~~~~~~~~~
internal_error(char const*, ...), at gcc/gcc/diagnostic-global-context.cc:517
fancy_abort(char const*, int, char const*), at gcc/gcc/diagnostic.cc:1803
comptypes_check_enum_int(tree_node*, tree_node*, bool*), at gcc/gcc/c/c-typeck.cc:1519
...
Link: https://archive.org/download/grsecurity/grsecurity-3.1-5.10.41-202105280954.patch.gz [1]
Reported-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Closes: https://github.com/KSPP/linux/issues/367
Closes: https://lore.kernel.org/lkml/20250530000646.104457-1-thiago.bauermann@linaro.org/
Reported-by: Ingo Saitz <ingo@hannover.ccc.de>
Closes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1104745
Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin")
Tested-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Link: https://lore.kernel.org/r/20250530221824.work.623-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
scripts/gcc-plugins/gcc-common.h | 32 +++++++++++++++++++
scripts/gcc-plugins/randomize_layout_plugin.c | 22 ++++++-------
2 files changed, 43 insertions(+), 11 deletions(-)
diff --git a/scripts/gcc-plugins/gcc-common.h b/scripts/gcc-plugins/gcc-common.h
index cba1440993450..8658e9d220b69 100644
--- a/scripts/gcc-plugins/gcc-common.h
+++ b/scripts/gcc-plugins/gcc-common.h
@@ -137,6 +137,38 @@ static inline tree build_const_char_string(int len, const char *str)
return cstr;
}
+static inline void __add_type_attr(tree type, const char *attr, tree args)
+{
+ tree oldattr;
+
+ if (type == NULL_TREE)
+ return;
+ oldattr = lookup_attribute(attr, TYPE_ATTRIBUTES(type));
+ if (oldattr != NULL_TREE) {
+ gcc_assert(TREE_VALUE(oldattr) == args || TREE_VALUE(TREE_VALUE(oldattr)) == TREE_VALUE(args));
+ return;
+ }
+
+ TYPE_ATTRIBUTES(type) = copy_list(TYPE_ATTRIBUTES(type));
+ TYPE_ATTRIBUTES(type) = tree_cons(get_identifier(attr), args, TYPE_ATTRIBUTES(type));
+}
+
+static inline void add_type_attr(tree type, const char *attr, tree args)
+{
+ tree main_variant = TYPE_MAIN_VARIANT(type);
+
+ __add_type_attr(TYPE_CANONICAL(type), attr, args);
+ __add_type_attr(TYPE_CANONICAL(main_variant), attr, args);
+ __add_type_attr(main_variant, attr, args);
+
+ for (type = TYPE_NEXT_VARIANT(main_variant); type; type = TYPE_NEXT_VARIANT(type)) {
+ if (!lookup_attribute(attr, TYPE_ATTRIBUTES(type)))
+ TYPE_ATTRIBUTES(type) = TYPE_ATTRIBUTES(main_variant);
+
+ __add_type_attr(TYPE_CANONICAL(type), attr, args);
+ }
+}
+
#define PASS_INFO(NAME, REF, ID, POS) \
struct register_pass_info NAME##_pass_info = { \
.pass = make_##NAME##_pass(), \
diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
index a8595df5fb6e8..24155ce812664 100644
--- a/scripts/gcc-plugins/randomize_layout_plugin.c
+++ b/scripts/gcc-plugins/randomize_layout_plugin.c
@@ -95,6 +95,9 @@ static tree handle_randomize_layout_attr(tree *node, tree name, tree args, int f
if (TYPE_P(*node)) {
type = *node;
+ } else if (TREE_CODE(*node) == FIELD_DECL) {
+ *no_add_attrs = false;
+ return NULL_TREE;
} else {
gcc_assert(TREE_CODE(*node) == TYPE_DECL);
type = TREE_TYPE(*node);
@@ -381,15 +384,14 @@ static int relayout_struct(tree type)
TREE_CHAIN(newtree[i]) = newtree[i+1];
TREE_CHAIN(newtree[num_fields - 1]) = NULL_TREE;
+ add_type_attr(type, "randomize_performed", NULL_TREE);
+ add_type_attr(type, "designated_init", NULL_TREE);
+ if (has_flexarray)
+ add_type_attr(type, "has_flexarray", NULL_TREE);
+
main_variant = TYPE_MAIN_VARIANT(type);
- for (variant = main_variant; variant; variant = TYPE_NEXT_VARIANT(variant)) {
+ for (variant = main_variant; variant; variant = TYPE_NEXT_VARIANT(variant))
TYPE_FIELDS(variant) = newtree[0];
- TYPE_ATTRIBUTES(variant) = copy_list(TYPE_ATTRIBUTES(variant));
- TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("randomize_performed"), NULL_TREE, TYPE_ATTRIBUTES(variant));
- TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("designated_init"), NULL_TREE, TYPE_ATTRIBUTES(variant));
- if (has_flexarray)
- TYPE_ATTRIBUTES(type) = tree_cons(get_identifier("has_flexarray"), NULL_TREE, TYPE_ATTRIBUTES(type));
- }
/*
* force a re-layout of the main variant
@@ -457,10 +459,8 @@ static void randomize_type(tree type)
if (lookup_attribute("randomize_layout", TYPE_ATTRIBUTES(TYPE_MAIN_VARIANT(type))) || is_pure_ops_struct(type))
relayout_struct(type);
- for (variant = TYPE_MAIN_VARIANT(type); variant; variant = TYPE_NEXT_VARIANT(variant)) {
- TYPE_ATTRIBUTES(type) = copy_list(TYPE_ATTRIBUTES(type));
- TYPE_ATTRIBUTES(type) = tree_cons(get_identifier("randomize_considered"), NULL_TREE, TYPE_ATTRIBUTES(type));
- }
+ add_type_attr(type, "randomize_considered", NULL_TREE);
+
#ifdef __DEBUG_PLUGIN
fprintf(stderr, "Marking randomize_considered on struct %s\n", ORIG_TYPE_NAME(type));
#ifdef __DEBUG_VERBOSE
--
2.50.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-09-05 15:52 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-06-05 8:43 FAILED: patch "[PATCH] randstruct: gcc-plugin: Fix attribute addition" failed to apply to 5.15-stable tree gregkh
2025-09-05 15:52 ` [PATCH 5.15.y 1/2] randstruct: gcc-plugin: Remove bogus void member Sasha Levin
2025-09-05 15:52 ` [PATCH 5.15.y 2/2] randstruct: gcc-plugin: Fix attribute addition Sasha Levin
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox