commit 7e0438f83dc769465ee663bb5dcf8cc154940712 upstream.
The following sequence of operations results in a refcount warning:
1. Open device /dev/tpmrm.
2. Remove module tpm_tis_spi.
3. Write a TPM command to the file descriptor opened at step 1.
------------[ cut here ]------------
WARNING: CPU: 3 PID: 1161 at lib/refcount.c:25 kobject_get+0xa0/0xa4
refcount_t: addition on 0; use-after-free.
Modules linked in: tpm_tis_spi tpm_tis_core tpm mdio_bcm_unimac brcmfmac
sha256_generic libsha256 sha256_arm hci_uart btbcm bluetooth cfg80211 vc4
brcmutil ecdh_generic ecc snd_soc_core crc32_arm_ce libaes
raspberrypi_hwmon ac97_bus snd_pcm_dmaengine bcm2711_thermal snd_pcm
snd_timer genet snd phy_generic soundcore [last unloaded: spi_bcm2835]
CPU: 3 PID: 1161 Comm: hold_open Not tainted 5.10.0ls-main-dirty #2
Hardware name: BCM2711
[<c0410c3c>] (unwind_backtrace) from [<c040b580>] (show_stack+0x10/0x14)
[<c040b580>] (show_stack) from [<c1092174>] (dump_stack+0xc4/0xd8)
[<c1092174>] (dump_stack) from [<c0445a30>] (__warn+0x104/0x108)
[<c0445a30>] (__warn) from [<c0445aa8>] (warn_slowpath_fmt+0x74/0xb8)
[<c0445aa8>] (warn_slowpath_fmt) from [<c08435d0>] (kobject_get+0xa0/0xa4)
[<c08435d0>] (kobject_get) from [<bf0a715c>] (tpm_try_get_ops+0x14/0x54 [tpm])
[<bf0a715c>] (tpm_try_get_ops [tpm]) from [<bf0a7d6c>] (tpm_common_write+0x38/0x60 [tpm])
[<bf0a7d6c>] (tpm_common_write [tpm]) from [<c05a7ac0>] (vfs_write+0xc4/0x3c0)
[<c05a7ac0>] (vfs_write) from [<c05a7ee4>] (ksys_write+0x58/0xcc)
[<c05a7ee4>] (ksys_write) from [<c04001a0>] (ret_fast_syscall+0x0/0x4c)
Exception stack(0xc226bfa8 to 0xc226bff0)
bfa0: 00000000 000105b4 00000003 beafe664 00000014 00000000
bfc0: 00000000 000105b4 000103f8 00000004 00000000 00000000 b6f9c000 beafe684
bfe0: 0000006c beafe648 0001056c b6eb6944
---[ end trace d4b8409def9b8b1f ]---
The reason for this warning is the attempt to get the chip->dev reference
in tpm_common_write() although the reference counter is already zero.
Since commit 8979b02aaf1d ("tpm: Fix reference count to main device") the
extra reference used to prevent a premature zero counter is never taken,
because the required TPM_CHIP_FLAG_TPM2 flag is never set.
Fix this by moving the TPM 2 character device handling from
tpm_chip_alloc() to tpm_add_char_device() which is called at a later point
in time when the flag has been set in case of TPM2.
Commit fdc915f7f719 ("tpm: expose spaces via a device link /dev/tpmrm<n>")
already introduced function tpm_devs_release() to release the extra
reference but did not implement the required put on chip->devs that results
in the call of this function.
Fix this by putting chip->devs in tpm_chip_unregister().
Finally move the new implementation for the TPM 2 handling into a new
function to avoid multiple checks for the TPM_CHIP_FLAG_TPM2 flag in the
good case and error cases.
Cc: stable(a)vger.kernel.org
Fixes: fdc915f7f719 ("tpm: expose spaces via a device link /dev/tpmrm<n>")
Fixes: 8979b02aaf1d ("tpm: Fix reference count to main device")
Co-developed-by: Jason Gunthorpe <jgg(a)ziepe.ca>
Signed-off-by: Jason Gunthorpe <jgg(a)ziepe.ca>
Signed-off-by: Lino Sanfilippo <LinoSanfilippo(a)gmx.de>
Tested-by: Stefan Berger <stefanb(a)linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg(a)nvidia.com>
Reviewed-by: Jarkko Sakkinen <jarkko(a)kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko(a)kernel.org>
---
drivers/char/tpm/tpm-chip.c | 46 +++++--------------------
drivers/char/tpm/tpm.h | 2 ++
drivers/char/tpm/tpm2-space.c | 65 +++++++++++++++++++++++++++++++++++
3 files changed, 75 insertions(+), 38 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index df37e7b6a10a..65d800ecc996 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -274,14 +274,6 @@ static void tpm_dev_release(struct device *dev)
kfree(chip);
}
-static void tpm_devs_release(struct device *dev)
-{
- struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs);
-
- /* release the master device reference */
- put_device(&chip->dev);
-}
-
/**
* tpm_class_shutdown() - prepare the TPM device for loss of power.
* @dev: device to which the chip is associated.
@@ -344,7 +336,6 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
chip->dev_num = rc;
device_initialize(&chip->dev);
- device_initialize(&chip->devs);
chip->dev.class = tpm_class;
chip->dev.class->shutdown_pre = tpm_class_shutdown;
@@ -352,29 +343,12 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
chip->dev.parent = pdev;
chip->dev.groups = chip->groups;
- chip->devs.parent = pdev;
- chip->devs.class = tpmrm_class;
- chip->devs.release = tpm_devs_release;
- /* get extra reference on main device to hold on
- * behalf of devs. This holds the chip structure
- * while cdevs is in use. The corresponding put
- * is in the tpm_devs_release (TPM2 only)
- */
- if (chip->flags & TPM_CHIP_FLAG_TPM2)
- get_device(&chip->dev);
-
if (chip->dev_num == 0)
chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
else
chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
- chip->devs.devt =
- MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);
-
rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num);
- if (rc)
- goto out;
- rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num);
if (rc)
goto out;
@@ -382,9 +356,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
cdev_init(&chip->cdev, &tpm_fops);
- cdev_init(&chip->cdevs, &tpmrm_fops);
chip->cdev.owner = THIS_MODULE;
- chip->cdevs.owner = THIS_MODULE;
rc = tpm2_init_space(&chip->work_space, TPM2_SPACE_BUFFER_SIZE);
if (rc) {
@@ -396,7 +368,6 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
return chip;
out:
- put_device(&chip->devs);
put_device(&chip->dev);
return ERR_PTR(rc);
}
@@ -445,14 +416,9 @@ static int tpm_add_char_device(struct tpm_chip *chip)
}
if (chip->flags & TPM_CHIP_FLAG_TPM2) {
- rc = cdev_device_add(&chip->cdevs, &chip->devs);
- if (rc) {
- dev_err(&chip->devs,
- "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
- dev_name(&chip->devs), MAJOR(chip->devs.devt),
- MINOR(chip->devs.devt), rc);
- return rc;
- }
+ rc = tpm_devs_add(chip);
+ if (rc)
+ goto err_del_cdev;
}
/* Make the chip available. */
@@ -460,6 +426,10 @@ static int tpm_add_char_device(struct tpm_chip *chip)
idr_replace(&dev_nums_idr, chip, chip->dev_num);
mutex_unlock(&idr_lock);
+ return 0;
+
+err_del_cdev:
+ cdev_device_del(&chip->cdev, &chip->dev);
return rc;
}
@@ -649,7 +619,7 @@ void tpm_chip_unregister(struct tpm_chip *chip)
hwrng_unregister(&chip->hwrng);
tpm_bios_log_teardown(chip);
if (chip->flags & TPM_CHIP_FLAG_TPM2)
- cdev_device_del(&chip->cdevs, &chip->devs);
+ tpm_devs_remove(chip);
tpm_del_char_device(chip);
}
EXPORT_SYMBOL_GPL(tpm_chip_unregister);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 283f78211c3a..2163c6ee0d36 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -234,6 +234,8 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
size_t cmdsiz);
int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, void *buf,
size_t *bufsiz);
+int tpm_devs_add(struct tpm_chip *chip);
+void tpm_devs_remove(struct tpm_chip *chip);
void tpm_bios_log_setup(struct tpm_chip *chip);
void tpm_bios_log_teardown(struct tpm_chip *chip);
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 97e916856cf3..265ec72b1d81 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -574,3 +574,68 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
dev_err(&chip->dev, "%s: error %d\n", __func__, rc);
return rc;
}
+
+/*
+ * Put the reference to the main device.
+ */
+static void tpm_devs_release(struct device *dev)
+{
+ struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs);
+
+ /* release the master device reference */
+ put_device(&chip->dev);
+}
+
+/*
+ * Remove the device file for exposed TPM spaces and release the device
+ * reference. This may also release the reference to the master device.
+ */
+void tpm_devs_remove(struct tpm_chip *chip)
+{
+ cdev_device_del(&chip->cdevs, &chip->devs);
+ put_device(&chip->devs);
+}
+
+/*
+ * Add a device file to expose TPM spaces. Also take a reference to the
+ * main device.
+ */
+int tpm_devs_add(struct tpm_chip *chip)
+{
+ int rc;
+
+ device_initialize(&chip->devs);
+ chip->devs.parent = chip->dev.parent;
+ chip->devs.class = tpmrm_class;
+
+ /*
+ * Get extra reference on main device to hold on behalf of devs.
+ * This holds the chip structure while cdevs is in use. The
+ * corresponding put is in the tpm_devs_release.
+ */
+ get_device(&chip->dev);
+ chip->devs.release = tpm_devs_release;
+ chip->devs.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);
+ cdev_init(&chip->cdevs, &tpmrm_fops);
+ chip->cdevs.owner = THIS_MODULE;
+
+ rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num);
+ if (rc)
+ goto err_put_devs;
+
+ rc = cdev_device_add(&chip->cdevs, &chip->devs);
+ if (rc) {
+ dev_err(&chip->devs,
+ "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
+ dev_name(&chip->devs), MAJOR(chip->devs.devt),
+ MINOR(chip->devs.devt), rc);
+ goto err_put_devs;
+ }
+
+ return 0;
+
+err_put_devs:
+ put_device(&chip->devs);
+
+ return rc;
+}
--
2.35.1
commit 7e0438f83dc769465ee663bb5dcf8cc154940712 upstream.
The following sequence of operations results in a refcount warning:
1. Open device /dev/tpmrm.
2. Remove module tpm_tis_spi.
3. Write a TPM command to the file descriptor opened at step 1.
------------[ cut here ]------------
WARNING: CPU: 3 PID: 1161 at lib/refcount.c:25 kobject_get+0xa0/0xa4
refcount_t: addition on 0; use-after-free.
Modules linked in: tpm_tis_spi tpm_tis_core tpm mdio_bcm_unimac brcmfmac
sha256_generic libsha256 sha256_arm hci_uart btbcm bluetooth cfg80211 vc4
brcmutil ecdh_generic ecc snd_soc_core crc32_arm_ce libaes
raspberrypi_hwmon ac97_bus snd_pcm_dmaengine bcm2711_thermal snd_pcm
snd_timer genet snd phy_generic soundcore [last unloaded: spi_bcm2835]
CPU: 3 PID: 1161 Comm: hold_open Not tainted 5.10.0ls-main-dirty #2
Hardware name: BCM2711
[<c0410c3c>] (unwind_backtrace) from [<c040b580>] (show_stack+0x10/0x14)
[<c040b580>] (show_stack) from [<c1092174>] (dump_stack+0xc4/0xd8)
[<c1092174>] (dump_stack) from [<c0445a30>] (__warn+0x104/0x108)
[<c0445a30>] (__warn) from [<c0445aa8>] (warn_slowpath_fmt+0x74/0xb8)
[<c0445aa8>] (warn_slowpath_fmt) from [<c08435d0>] (kobject_get+0xa0/0xa4)
[<c08435d0>] (kobject_get) from [<bf0a715c>] (tpm_try_get_ops+0x14/0x54 [tpm])
[<bf0a715c>] (tpm_try_get_ops [tpm]) from [<bf0a7d6c>] (tpm_common_write+0x38/0x60 [tpm])
[<bf0a7d6c>] (tpm_common_write [tpm]) from [<c05a7ac0>] (vfs_write+0xc4/0x3c0)
[<c05a7ac0>] (vfs_write) from [<c05a7ee4>] (ksys_write+0x58/0xcc)
[<c05a7ee4>] (ksys_write) from [<c04001a0>] (ret_fast_syscall+0x0/0x4c)
Exception stack(0xc226bfa8 to 0xc226bff0)
bfa0: 00000000 000105b4 00000003 beafe664 00000014 00000000
bfc0: 00000000 000105b4 000103f8 00000004 00000000 00000000 b6f9c000 beafe684
bfe0: 0000006c beafe648 0001056c b6eb6944
---[ end trace d4b8409def9b8b1f ]---
The reason for this warning is the attempt to get the chip->dev reference
in tpm_common_write() although the reference counter is already zero.
Since commit 8979b02aaf1d ("tpm: Fix reference count to main device") the
extra reference used to prevent a premature zero counter is never taken,
because the required TPM_CHIP_FLAG_TPM2 flag is never set.
Fix this by moving the TPM 2 character device handling from
tpm_chip_alloc() to tpm_add_char_device() which is called at a later point
in time when the flag has been set in case of TPM2.
Commit fdc915f7f719 ("tpm: expose spaces via a device link /dev/tpmrm<n>")
already introduced function tpm_devs_release() to release the extra
reference but did not implement the required put on chip->devs that results
in the call of this function.
Fix this by putting chip->devs in tpm_chip_unregister().
Finally move the new implementation for the TPM 2 handling into a new
function to avoid multiple checks for the TPM_CHIP_FLAG_TPM2 flag in the
good case and error cases.
Cc: stable(a)vger.kernel.org
Fixes: fdc915f7f719 ("tpm: expose spaces via a device link /dev/tpmrm<n>")
Fixes: 8979b02aaf1d ("tpm: Fix reference count to main device")
Co-developed-by: Jason Gunthorpe <jgg(a)ziepe.ca>
Signed-off-by: Jason Gunthorpe <jgg(a)ziepe.ca>
Signed-off-by: Lino Sanfilippo <LinoSanfilippo(a)gmx.de>
Tested-by: Stefan Berger <stefanb(a)linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg(a)nvidia.com>
Reviewed-by: Jarkko Sakkinen <jarkko(a)kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko(a)kernel.org>
---
drivers/char/tpm/tpm-chip.c | 46 +++++--------------------
drivers/char/tpm/tpm.h | 2 ++
drivers/char/tpm/tpm2-space.c | 65 +++++++++++++++++++++++++++++++++++
3 files changed, 75 insertions(+), 38 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index df37e7b6a10a..65d800ecc996 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -274,14 +274,6 @@ static void tpm_dev_release(struct device *dev)
kfree(chip);
}
-static void tpm_devs_release(struct device *dev)
-{
- struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs);
-
- /* release the master device reference */
- put_device(&chip->dev);
-}
-
/**
* tpm_class_shutdown() - prepare the TPM device for loss of power.
* @dev: device to which the chip is associated.
@@ -344,7 +336,6 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
chip->dev_num = rc;
device_initialize(&chip->dev);
- device_initialize(&chip->devs);
chip->dev.class = tpm_class;
chip->dev.class->shutdown_pre = tpm_class_shutdown;
@@ -352,29 +343,12 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
chip->dev.parent = pdev;
chip->dev.groups = chip->groups;
- chip->devs.parent = pdev;
- chip->devs.class = tpmrm_class;
- chip->devs.release = tpm_devs_release;
- /* get extra reference on main device to hold on
- * behalf of devs. This holds the chip structure
- * while cdevs is in use. The corresponding put
- * is in the tpm_devs_release (TPM2 only)
- */
- if (chip->flags & TPM_CHIP_FLAG_TPM2)
- get_device(&chip->dev);
-
if (chip->dev_num == 0)
chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
else
chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
- chip->devs.devt =
- MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);
-
rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num);
- if (rc)
- goto out;
- rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num);
if (rc)
goto out;
@@ -382,9 +356,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
cdev_init(&chip->cdev, &tpm_fops);
- cdev_init(&chip->cdevs, &tpmrm_fops);
chip->cdev.owner = THIS_MODULE;
- chip->cdevs.owner = THIS_MODULE;
rc = tpm2_init_space(&chip->work_space, TPM2_SPACE_BUFFER_SIZE);
if (rc) {
@@ -396,7 +368,6 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
return chip;
out:
- put_device(&chip->devs);
put_device(&chip->dev);
return ERR_PTR(rc);
}
@@ -445,14 +416,9 @@ static int tpm_add_char_device(struct tpm_chip *chip)
}
if (chip->flags & TPM_CHIP_FLAG_TPM2) {
- rc = cdev_device_add(&chip->cdevs, &chip->devs);
- if (rc) {
- dev_err(&chip->devs,
- "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
- dev_name(&chip->devs), MAJOR(chip->devs.devt),
- MINOR(chip->devs.devt), rc);
- return rc;
- }
+ rc = tpm_devs_add(chip);
+ if (rc)
+ goto err_del_cdev;
}
/* Make the chip available. */
@@ -460,6 +426,10 @@ static int tpm_add_char_device(struct tpm_chip *chip)
idr_replace(&dev_nums_idr, chip, chip->dev_num);
mutex_unlock(&idr_lock);
+ return 0;
+
+err_del_cdev:
+ cdev_device_del(&chip->cdev, &chip->dev);
return rc;
}
@@ -649,7 +619,7 @@ void tpm_chip_unregister(struct tpm_chip *chip)
hwrng_unregister(&chip->hwrng);
tpm_bios_log_teardown(chip);
if (chip->flags & TPM_CHIP_FLAG_TPM2)
- cdev_device_del(&chip->cdevs, &chip->devs);
+ tpm_devs_remove(chip);
tpm_del_char_device(chip);
}
EXPORT_SYMBOL_GPL(tpm_chip_unregister);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 283f78211c3a..2163c6ee0d36 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -234,6 +234,8 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
size_t cmdsiz);
int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, void *buf,
size_t *bufsiz);
+int tpm_devs_add(struct tpm_chip *chip);
+void tpm_devs_remove(struct tpm_chip *chip);
void tpm_bios_log_setup(struct tpm_chip *chip);
void tpm_bios_log_teardown(struct tpm_chip *chip);
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 97e916856cf3..265ec72b1d81 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -574,3 +574,68 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
dev_err(&chip->dev, "%s: error %d\n", __func__, rc);
return rc;
}
+
+/*
+ * Put the reference to the main device.
+ */
+static void tpm_devs_release(struct device *dev)
+{
+ struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs);
+
+ /* release the master device reference */
+ put_device(&chip->dev);
+}
+
+/*
+ * Remove the device file for exposed TPM spaces and release the device
+ * reference. This may also release the reference to the master device.
+ */
+void tpm_devs_remove(struct tpm_chip *chip)
+{
+ cdev_device_del(&chip->cdevs, &chip->devs);
+ put_device(&chip->devs);
+}
+
+/*
+ * Add a device file to expose TPM spaces. Also take a reference to the
+ * main device.
+ */
+int tpm_devs_add(struct tpm_chip *chip)
+{
+ int rc;
+
+ device_initialize(&chip->devs);
+ chip->devs.parent = chip->dev.parent;
+ chip->devs.class = tpmrm_class;
+
+ /*
+ * Get extra reference on main device to hold on behalf of devs.
+ * This holds the chip structure while cdevs is in use. The
+ * corresponding put is in the tpm_devs_release.
+ */
+ get_device(&chip->dev);
+ chip->devs.release = tpm_devs_release;
+ chip->devs.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);
+ cdev_init(&chip->cdevs, &tpmrm_fops);
+ chip->cdevs.owner = THIS_MODULE;
+
+ rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num);
+ if (rc)
+ goto err_put_devs;
+
+ rc = cdev_device_add(&chip->cdevs, &chip->devs);
+ if (rc) {
+ dev_err(&chip->devs,
+ "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
+ dev_name(&chip->devs), MAJOR(chip->devs.devt),
+ MINOR(chip->devs.devt), rc);
+ goto err_put_devs;
+ }
+
+ return 0;
+
+err_put_devs:
+ put_device(&chip->devs);
+
+ return rc;
+}
--
2.35.1
The bug is here:
dev = new_dev->dev;
The list iterator 'new_dev' will point to a bogus position containing
HEAD if the list is empty or no element is found. This case must
be checked before any use of the iterator, otherwise it will lead
to a invalid memory access.
To fix this bug, add an check. Use a new variable 'iter' as the
list iterator, while use the old variable 'new_dev' as a dedicated
pointer to point to the found element.
Cc: stable(a)vger.kernel.org
Fixes: deaa51465105a ("PM / OPP: Add debugfs support")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong(a)gmail.com>
---
drivers/opp/debugfs.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/opp/debugfs.c b/drivers/opp/debugfs.c
index 596c185b5dda..a4476985e4ce 100644
--- a/drivers/opp/debugfs.c
+++ b/drivers/opp/debugfs.c
@@ -187,14 +187,19 @@ void opp_debug_register(struct opp_device *opp_dev, struct opp_table *opp_table)
static void opp_migrate_dentry(struct opp_device *opp_dev,
struct opp_table *opp_table)
{
- struct opp_device *new_dev;
+ struct opp_device *new_dev = NULL, *iter;
const struct device *dev;
struct dentry *dentry;
/* Look for next opp-dev */
- list_for_each_entry(new_dev, &opp_table->dev_list, node)
- if (new_dev != opp_dev)
+ list_for_each_entry(iter, &opp_table->dev_list, node)
+ if (iter != opp_dev) {
+ new_dev = iter;
break;
+ }
+
+ if (!new_dev)
+ return;
/* new_dev is guaranteed to be valid here */
dev = new_dev->dev;
--
2.17.1
عزيزي المستفيد،
لقد أرسلت لك هذه الرسالة قبل شهر ، لكني لم أسمع منك ، لا
أنا متأكد من أنك تلقيتها ، ولهذا أرسلتها لك مرة أخرى ،
بادئ ذي بدء ، أنا السيدة كريستالينا جورجيفا ، المدير العام و
رئيس صندوق النقد الدولي.
في الواقع ، لقد قمنا باستعراض جميع المعوقات والقضايا المحيطة
معاملتك غير المكتملة وعدم قدرتك على سداد الرسوم
رسوم التحويل المفروضة عليك مقابل خيارات
التحويلات السابقة ، قم بزيارة موقعنا للتأكيد 38
° 53′56 ″ شمالاً 77 ° 2 ′ 39 غربًا
نحن مجلس الإدارة والبنك الدولي وصندوق النقد
الدولي (IMF) في واشنطن العاصمة ، مع وزارة
وزارة الخزانة الأمريكية وبعض وكالات التحقيق الأخرى
ذات الصلة هنا في الولايات المتحدة الأمريكية. قد أمر
وحدة تحويل المدفوعات الخارجية الخاصة بنا ، مصرف United Bank of
Africa Lome Togo ، لإصدار بطاقة فيزا لك ، حيث $
1.5 مليون من أموالك لسحب أكبر من أموالك.
خلال مسار تحقيقنا ، اكتشفنا مع
استياء من أن المسؤولين الفاسدين قد أخروا دفعك
البنك الذي يحاول تحويل أموالك إلى حساباتك
نشر.
واليوم نخطرك بأن أموالك قد تم إيداعها في بطاقة
تأشيرة من UBA Bank وهي أيضًا جاهزة للتسليم. حاليا
اتصل بمدير بنك UBA ، اسمه السيد توني
Elumelu ، البريد الإلكتروني: (Ubagroup.tgo12(a)gmail.com)
لإخبارك بكيفية الحصول على بطاقة فيزا الصراف الآلي الخاصة بك.
بإخلاص،
السيدة كريستالينا جورجيفا
Please apply this to stable 5.10.y, 5.15.y
---8<---
From: Kees Cook <keescook(a)chromium.org>
Upstream commit: 50d7bd38c3aa ("stddef: Introduce struct_group() helper macro")
Kernel code has a regular need to describe groups of members within a
structure usually when they need to be copied or initialized separately
from the rest of the surrounding structure. The generally accepted design
pattern in C is to use a named sub-struct:
struct foo {
int one;
struct {
int two;
int three, four;
} thing;
int five;
};
This would allow for traditional references and sizing:
memcpy(&dst.thing, &src.thing, sizeof(dst.thing));
However, doing this would mean that referencing struct members enclosed
by such named structs would always require including the sub-struct name
in identifiers:
do_something(dst.thing.three);
This has tended to be quite inflexible, especially when such groupings
need to be added to established code which causes huge naming churn.
Three workarounds exist in the kernel for this problem, and each have
other negative properties.
To avoid the naming churn, there is a design pattern of adding macro
aliases for the named struct:
#define f_three thing.three
This ends up polluting the global namespace, and makes it difficult to
search for identifiers.
Another common work-around in kernel code avoids the pollution by avoiding
the named struct entirely, instead identifying the group's boundaries using
either a pair of empty anonymous structs of a pair of zero-element arrays:
struct foo {
int one;
struct { } start;
int two;
int three, four;
struct { } finish;
int five;
};
struct foo {
int one;
int start[0];
int two;
int three, four;
int finish[0];
int five;
};
This allows code to avoid needing to use a sub-struct named for member
references within the surrounding structure, but loses the benefits of
being able to actually use such a struct, making it rather fragile. Using
these requires open-coded calculation of sizes and offsets. The efforts
made to avoid common mistakes include lots of comments, or adding various
BUILD_BUG_ON()s. Such code is left with no way for the compiler to reason
about the boundaries (e.g. the "start" object looks like it's 0 bytes
in length), making bounds checking depend on open-coded calculations:
if (length > offsetof(struct foo, finish) -
offsetof(struct foo, start))
return -EINVAL;
memcpy(&dst.start, &src.start, offsetof(struct foo, finish) -
offsetof(struct foo, start));
However, the vast majority of places in the kernel that operate on
groups of members do so without any identification of the grouping,
relying either on comments or implicit knowledge of the struct contents,
which is even harder for the compiler to reason about, and results in
even more fragile manual sizing, usually depending on member locations
outside of the region (e.g. to copy "two" and "three", use the start of
"four" to find the size):
BUILD_BUG_ON((offsetof(struct foo, four) <
offsetof(struct foo, two)) ||
(offsetof(struct foo, four) <
offsetof(struct foo, three));
if (length > offsetof(struct foo, four) -
offsetof(struct foo, two))
return -EINVAL;
memcpy(&dst.two, &src.two, length);
In order to have a regular programmatic way to describe a struct
region that can be used for references and sizing, can be examined for
bounds checking, avoids forcing the use of intermediate identifiers,
and avoids polluting the global namespace, introduce the struct_group()
macro. This macro wraps the member declarations to create an anonymous
union of an anonymous struct (no intermediate name) and a named struct
(for references and sizing):
struct foo {
int one;
struct_group(thing,
int two;
int three, four;
);
int five;
};
if (length > sizeof(src.thing))
return -EINVAL;
memcpy(&dst.thing, &src.thing, length);
do_something(dst.three);
There are some rare cases where the resulting struct_group() needs
attributes added, so struct_group_attr() is also introduced to allow
for specifying struct attributes (e.g. __align(x) or __packed).
Additionally, there are places where such declarations would like to
have the struct be tagged, so struct_group_tagged() is added.
Given there is a need for a handful of UAPI uses too, the underlying
__struct_group() macro has been defined in UAPI so it can be used there
too.
To avoid confusing scripts/kernel-doc, hide the macro from its struct
parsing.
Co-developed-by: Keith Packard <keithp(a)keithp.com>
Signed-off-by: Keith Packard <keithp(a)keithp.com>
Acked-by: Gustavo A. R. Silva <gustavoars(a)kernel.org>
Link: https://lore.kernel.org/lkml/20210728023217.GC35706@embeddedor
Enhanced-by: Rasmus Villemoes <linux(a)rasmusvillemoes.dk>
Link: https://lore.kernel.org/lkml/41183a98-bdb9-4ad6-7eab-5a7292a6df84@rasmusvil…
Enhanced-by: Dan Williams <dan.j.williams(a)intel.com>
Link: https://lore.kernel.org/lkml/1d9a2e6df2a9a35b2cdd50a9a68cac5991e7e5f0.camel…
Enhanced-by: Daniel Vetter <daniel.vetter(a)ffwll.ch>
Link: https://lore.kernel.org/lkml/YQKa76A6XuFqgM03@phenom.ffwll.local
Acked-by: Dan Williams <dan.j.williams(a)intel.com>
Signed-off-by: Kees Cook <keescook(a)chromium.org>
Signed-off-by: Tadeusz Struk <tadeusz.struk(a)linaro.org>
---
include/linux/stddef.h | 48 +++++++++++++++++++++++++++++++++++++
include/uapi/linux/stddef.h | 24 +++++++++++++++++++
2 files changed, 72 insertions(+)
diff --git a/include/linux/stddef.h b/include/linux/stddef.h
index 998a4ba28eba..938216f8ab7e 100644
--- a/include/linux/stddef.h
+++ b/include/linux/stddef.h
@@ -36,4 +36,52 @@ enum {
#define offsetofend(TYPE, MEMBER) \
(offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER))
+/**
+ * struct_group() - Wrap a set of declarations in a mirrored struct
+ *
+ * @NAME: The identifier name of the mirrored sub-struct
+ * @MEMBERS: The member declarations for the mirrored structs
+ *
+ * Used to create an anonymous union of two structs with identical
+ * layout and size: one anonymous and one named. The former can be
+ * used normally without sub-struct naming, and the latter can be
+ * used to reason about the start, end, and size of the group of
+ * struct members.
+ */
+#define struct_group(NAME, MEMBERS...) \
+ __struct_group(/* no tag */, NAME, /* no attrs */, MEMBERS)
+
+/**
+ * struct_group_attr() - Create a struct_group() with trailing attributes
+ *
+ * @NAME: The identifier name of the mirrored sub-struct
+ * @ATTRS: Any struct attributes to apply
+ * @MEMBERS: The member declarations for the mirrored structs
+ *
+ * Used to create an anonymous union of two structs with identical
+ * layout and size: one anonymous and one named. The former can be
+ * used normally without sub-struct naming, and the latter can be
+ * used to reason about the start, end, and size of the group of
+ * struct members. Includes structure attributes argument.
+ */
+#define struct_group_attr(NAME, ATTRS, MEMBERS...) \
+ __struct_group(/* no tag */, NAME, ATTRS, MEMBERS)
+
+/**
+ * struct_group_tagged() - Create a struct_group with a reusable tag
+ *
+ * @TAG: The tag name for the named sub-struct
+ * @NAME: The identifier name of the mirrored sub-struct
+ * @MEMBERS: The member declarations for the mirrored structs
+ *
+ * Used to create an anonymous union of two structs with identical
+ * layout and size: one anonymous and one named. The former can be
+ * used normally without sub-struct naming, and the latter can be
+ * used to reason about the start, end, and size of the group of
+ * struct members. Includes struct tag argument for the named copy,
+ * so the specified layout can be reused later.
+ */
+#define struct_group_tagged(TAG, NAME, MEMBERS...) \
+ __struct_group(TAG, NAME, /* no attrs */, MEMBERS)
+
#endif
diff --git a/include/uapi/linux/stddef.h b/include/uapi/linux/stddef.h
index ee8220f8dcf5..9f5da295ff1c 100644
--- a/include/uapi/linux/stddef.h
+++ b/include/uapi/linux/stddef.h
@@ -1,6 +1,30 @@
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#include <linux/compiler_types.h>
+#ifndef _UAPI_LINUX_STDDEF_H
+#define _UAPI_LINUX_STDDEF_H
#ifndef __always_inline
#define __always_inline inline
#endif
+
+/**
+ * __struct_group() - Create a mirrored named and anonyomous struct
+ *
+ * @TAG: The tag name for the named sub-struct (usually empty)
+ * @NAME: The identifier name of the mirrored sub-struct
+ * @ATTRS: Any struct attributes (usually empty)
+ * @MEMBERS: The member declarations for the mirrored structs
+ *
+ * Used to create an anonymous union of two structs with identical layout
+ * and size: one anonymous and one named. The former's members can be used
+ * normally without sub-struct naming, and the latter can be used to
+ * reason about the start, end, and size of the group of struct members.
+ * The named struct can also be explicitly tagged for layer reuse, as well
+ * as both having struct attributes appended.
+ */
+#define __struct_group(TAG, NAME, ATTRS, MEMBERS...) \
+ union { \
+ struct { MEMBERS } ATTRS; \
+ struct TAG { MEMBERS } ATTRS NAME; \
+ }
+#endif
--
2.35.1