x86/events/amd/iommu: Fix sysfs type mismatch

PATCH Applied Nathan Chancellor 3 participants 8 messages Apr 15, 2021 – Apr 16, 2021

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Nathan Chancellor

author

2021-04-15 00:13 UTC #0 lore raw

PATCH 1/2 x86/events/amd/iommu: Fix sysfs type mismatch

dev_attr_show() calls _iommu_event_show() via an indirect call but _iommu_event_show()'s type does not currently match the type of the show() member in 'struct device_attribute', resulting in a Control Flow Integrity violation.

$ cat /sys/devices/amd_iommu_1/events/mem_dte_hit
csource=0x0a

$ dmesg | grep "CFI failure"
[ 3526.735140] CFI failure (target: _iommu_event_show...):

Change _iommu_event_show() and 'struct amd_iommu_event_desc' to 'struct device_attribute' so that there is no more CFI violation.

Link https://github.com/ClangBuiltLinux/linux/issues/1350

Fixes 7be6296fdd75 ("perf/x86/amd: AMD IOMMU Performance Counter PERF uncore PMU implementation")

Signed-off-by Nathan Chancellor <[email protected]>

---
 arch/x86/events/amd/iommu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

arch/x86/events/amd/iommu.c +3 -3

index be50ef8572cc..6a98a7651621 100644
@@ -81,12 +81,12 @@ static struct attribute_group amd_iommu_events_group = {
 };
 
 struct amd_iommu_event_desc {
-	struct kobj_attribute attr;
+	struct device_attribute attr;
 	const char *event;
 };
 
-static ssize_t _iommu_event_show(struct kobject *kobj,
-				struct kobj_attribute *attr, char *buf)
+static ssize_t _iommu_event_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
 {
 	struct amd_iommu_event_desc *event =
 		container_of(attr, struct amd_iommu_event_desc, attr);

base-commit: d434405aaab7d0ebc516b68a8fc4100922d7f5ef

Signature · 1 line

2.31.1.272.g89b43f80a5

Nathan Chancellor

author

2021-04-15 00:13 UTC #1 lore raw

PATCH 2/2 perf/amd/uncore: Fix sysfs type mismatch

dev_attr_show() calls the __uncore_*_show() functions via an indirect call but their type does not currently match the type of the show() member in 'struct device_attribute', resulting in a Control Flow Integrity violation.

$ cat /sys/devices/amd_l3/format/umask
config:8-15

$ dmesg | grep "CFI failure"
[ 1258.174653] CFI failure (target: __uncore_umask_show...):

Update the type in the DEFINE_UNCORE_FORMAT_ATTR macro to match 'struct device_attribute' so that there is no more CFI violation.

Link https://github.com/ClangBuiltLinux/linux/issues/1350

Fixes 06f2c24584f3 ("perf/amd/uncore: Prepare to scale for more attributes that vary per family")

Signed-off-by Nathan Chancellor <[email protected]>

---
 arch/x86/events/amd/uncore.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

arch/x86/events/amd/uncore.c +3 -3

index 7f014d450bc2..582c0ffb5e98 100644
@@ -275,14 +275,14 @@ static struct attribute_group amd_uncore_attr_group = {
 };
 
 #define DEFINE_UNCORE_FORMAT_ATTR(_var, _name, _format)			\
-static ssize_t __uncore_##_var##_show(struct kobject *kobj,		\
-				struct kobj_attribute *attr,		\
+static ssize_t __uncore_##_var##_show(struct device *dev,		\
+				struct device_attribute *attr,		\
 				char *page)				\
 {									\
 	BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE);			\
 	return sprintf(page, _format "\n");				\
 }									\
-static struct kobj_attribute format_attr_##_var =			\
+static struct device_attribute format_attr_##_var =			\
 	__ATTR(_name, 0444, __uncore_##_var##_show, NULL)
 
 DEFINE_UNCORE_FORMAT_ATTR(event12,	event,		"config:0-7,32-35");

Signature · 1 line

2.31.1.272.g89b43f80a5

tip-bot2 for Nathan Chancellor

merge bot Applied

2021-04-16 15:01 UTC #2 lore raw

[tip: perf/core] perf/amd/uncore: Fix sysfs type mismatch

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     b04c0cddff6d1d6656c7f7c08c0b8f07eb287564
Gitweb:        https://git.kernel.org/tip/b04c0cddff6d1d6656c7f7c08c0b8f07eb287564
Author:        Nathan Chancellor <[email protected]>
AuthorDate:    Wed, 14 Apr 2021 17:11:12 -07:00
Committer:     Peter Zijlstra <[email protected]>
CommitterDate: Fri, 16 Apr 2021 16:32:44 +02:00

perf/amd/uncore: Fix sysfs type mismatch

$ cat /sys/devices/amd_l3/format/umask
config:8-15

$ dmesg | grep "CFI failure"
[ 1258.174653] CFI failure (target: __uncore_umask_show...):

Update the type in the DEFINE_UNCORE_FORMAT_ATTR macro to match 'struct device_attribute' so that there is no more CFI violation.

Fixes 06f2c24584f3 ("perf/amd/uncore: Prepare to scale for more attributes that vary per family")

Signed-off-by Nathan Chancellor <[email protected]>

Signed-off-by Peter Zijlstra (Intel) <[email protected]>

Link https://lkml.kernel.org/r/[email protected] open here

---
 arch/x86/events/amd/uncore.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

arch/x86/events/amd/uncore.c +3 -3

index 7f014d4..582c0ff 100644
@@ -275,14 +275,14 @@ static struct attribute_group amd_uncore_attr_group = {
 };
 
 #define DEFINE_UNCORE_FORMAT_ATTR(_var, _name, _format)			\
-static ssize_t __uncore_##_var##_show(struct kobject *kobj,		\
-				struct kobj_attribute *attr,		\
+static ssize_t __uncore_##_var##_show(struct device *dev,		\
+				struct device_attribute *attr,		\
 				char *page)				\
 {									\
 	BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE);			\
 	return sprintf(page, _format "\n");				\
 }									\
-static struct kobj_attribute format_attr_##_var =			\
+static struct device_attribute format_attr_##_var =			\
 	__ATTR(_name, 0444, __uncore_##_var##_show, NULL)
 
 DEFINE_UNCORE_FORMAT_ATTR(event12,	event,		"config:0-7,32-35");

tip-bot2 for Nathan Chancellor

merge bot Applied

2021-04-16 17:13 UTC #3 lore raw

[tip: perf/core] perf/amd/uncore: Fix sysfs type mismatch

In reply to Nathan Chancellor

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     5deac80d4571dffb51f452f0027979d72259a1b9
Gitweb:        https://git.kernel.org/tip/5deac80d4571dffb51f452f0027979d72259a1b9
Author:        Nathan Chancellor <[email protected]>
AuthorDate:    Wed, 14 Apr 2021 17:11:12 -07:00
Committer:     Peter Zijlstra <[email protected]>
CommitterDate: Fri, 16 Apr 2021 18:58:52 +02:00

perf/amd/uncore: Fix sysfs type mismatch

$ cat /sys/devices/amd_l3/format/umask
config:8-15

$ dmesg | grep "CFI failure"
[ 1258.174653] CFI failure (target: __uncore_umask_show...):

Update the type in the DEFINE_UNCORE_FORMAT_ATTR macro to match 'struct device_attribute' so that there is no more CFI violation.

Fixes 06f2c24584f3 ("perf/amd/uncore: Prepare to scale for more attributes that vary per family")

Signed-off-by Nathan Chancellor <[email protected]>

Signed-off-by Peter Zijlstra (Intel) <[email protected]>

Link https://lkml.kernel.org/r/[email protected] open here

---
 arch/x86/events/amd/uncore.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

arch/x86/events/amd/uncore.c +3 -3

index 7f014d4..582c0ff 100644
@@ -275,14 +275,14 @@ static struct attribute_group amd_uncore_attr_group = {
 };
 
 #define DEFINE_UNCORE_FORMAT_ATTR(_var, _name, _format)			\
-static ssize_t __uncore_##_var##_show(struct kobject *kobj,		\
-				struct kobj_attribute *attr,		\
+static ssize_t __uncore_##_var##_show(struct device *dev,		\
+				struct device_attribute *attr,		\
 				char *page)				\
 {									\
 	BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE);			\
 	return sprintf(page, _format "\n");				\
 }									\
-static struct kobj_attribute format_attr_##_var =			\
+static struct device_attribute format_attr_##_var =			\
 	__ATTR(_name, 0444, __uncore_##_var##_show, NULL)
 
 DEFINE_UNCORE_FORMAT_ATTR(event12,	event,		"config:0-7,32-35");

Christoph Hellwig

2021-04-15 07:54 UTC #4 lore raw

In reply to Nathan Chancellor

Quoted 4 lines · Nathan Chancellor

dev_attr_show() calls _iommu_event_show() via an indirect call but _iommu_event_show()'s type does not currently match the type of the show() member in 'struct device_attribute', resulting in a Control Flow Integrity violation.

While the fix looks fine I think we need to solve this kind of problem by better type checking. The fact that we can use the wong type here without a compiler warning is the real issue.

Nathan Chancellor

author

2021-04-15 14:47 UTC #5 lore raw

Quoted 9 lines · Christoph Hellwig

Quoted 4 lines · Nathan Chancellor
dev_attr_show() calls _iommu_event_show() via an indirect call but _iommu_event_show()'s type does not currently match the type of the show() member in 'struct device_attribute', resulting in a Control Flow Integrity violation.
While the fix looks fine I think we need to solve this kind of problem by better type checking. The fact that we can use the wong type here without a compiler warning is the real issue.

I agree. Unfortunately, it seems that is going to be a much longer tail project because of how pervasive this is (using container_of() + attributes to get callbacks).

https://lore.kernel.org/r/202006112217.2E6CE093@keescook/
https://lore.kernel.org/r/202104021823.64FA6119@keescook/

Cheers,
Nathan

tip-bot2 for Nathan Chancellor

merge bot Applied

2021-04-16 15:01 UTC #6 lore raw

In reply to Nathan Chancellor

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     bccae9d7b013bd708ece414f74defaee56790e1d
Gitweb:        https://git.kernel.org/tip/bccae9d7b013bd708ece414f74defaee56790e1d
Author:        Nathan Chancellor <[email protected]>
AuthorDate:    Wed, 14 Apr 2021 17:11:11 -07:00
Committer:     Peter Zijlstra <[email protected]>
CommitterDate: Fri, 16 Apr 2021 16:32:44 +02:00

x86/events/amd/iommu: Fix sysfs type mismatch

$ cat /sys/devices/amd_iommu_1/events/mem_dte_hit
csource=0x0a

$ dmesg | grep "CFI failure"
[ 3526.735140] CFI failure (target: _iommu_event_show...):

Change _iommu_event_show() and 'struct amd_iommu_event_desc' to 'struct device_attribute' so that there is no more CFI violation.

Fixes 7be6296fdd75 ("perf/x86/amd: AMD IOMMU Performance Counter PERF uncore PMU implementation")

Signed-off-by Nathan Chancellor <[email protected]>

Signed-off-by Peter Zijlstra (Intel) <[email protected]>

Link https://lkml.kernel.org/r/[email protected] open here

---
 arch/x86/events/amd/iommu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

arch/x86/events/amd/iommu.c +3 -3

index be50ef8..6a98a76 100644
@@ -81,12 +81,12 @@ static struct attribute_group amd_iommu_events_group = {
 };
 
 struct amd_iommu_event_desc {
-	struct kobj_attribute attr;
+	struct device_attribute attr;
 	const char *event;
 };
 
-static ssize_t _iommu_event_show(struct kobject *kobj,
-				struct kobj_attribute *attr, char *buf)
+static ssize_t _iommu_event_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
 {
 	struct amd_iommu_event_desc *event =
 		container_of(attr, struct amd_iommu_event_desc, attr);

tip-bot2 for Nathan Chancellor

merge bot Applied

2021-04-16 17:13 UTC #7 lore raw

In reply to Nathan Chancellor

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     de5bc7b425d4c27ae5faa00ea7eb6b9780b9a355
Gitweb:        https://git.kernel.org/tip/de5bc7b425d4c27ae5faa00ea7eb6b9780b9a355
Author:        Nathan Chancellor <[email protected]>
AuthorDate:    Wed, 14 Apr 2021 17:11:11 -07:00
Committer:     Peter Zijlstra <[email protected]>
CommitterDate: Fri, 16 Apr 2021 18:58:52 +02:00

x86/events/amd/iommu: Fix sysfs type mismatch

$ cat /sys/devices/amd_iommu_1/events/mem_dte_hit
csource=0x0a

$ dmesg | grep "CFI failure"
[ 3526.735140] CFI failure (target: _iommu_event_show...):

Change _iommu_event_show() and 'struct amd_iommu_event_desc' to 'struct device_attribute' so that there is no more CFI violation.

Fixes 7be6296fdd75 ("perf/x86/amd: AMD IOMMU Performance Counter PERF uncore PMU implementation")

Signed-off-by Nathan Chancellor <[email protected]>

Signed-off-by Peter Zijlstra (Intel) <[email protected]>

Link https://lkml.kernel.org/r/[email protected] open here

---
 arch/x86/events/amd/iommu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

arch/x86/events/amd/iommu.c +3 -3

index be50ef8..6a98a76 100644
@@ -81,12 +81,12 @@ static struct attribute_group amd_iommu_events_group = {
 };
 
 struct amd_iommu_event_desc {
-	struct kobj_attribute attr;
+	struct device_attribute attr;
 	const char *event;
 };
 
-static ssize_t _iommu_event_show(struct kobject *kobj,
-				struct kobj_attribute *attr, char *buf)
+static ssize_t _iommu_event_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
 {
 	struct amd_iommu_event_desc *event =
 		container_of(attr, struct amd_iommu_event_desc, attr);