| Message ID | 1613505191-4602-2-git-send-email-LinoSanfilippo@gmx.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RESEND,v5] tpm: fix reference counting for struct tpm_chip | expand |
On Tue, Feb 16, 2021 at 08:53:11PM +0100, Lino Sanfilippo wrote: > From: Lino Sanfilippo <l.sanfilippo@kunbus.com> > > 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@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@ziepe.ca> > Signed-off-by: Jason Gunthorpe <jgg@ziepe.ca> > Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com> > --- > drivers/char/tpm/tpm-chip.c | 48 +++++++++---------------------------------- > drivers/char/tpm/tpm.h | 1 + > drivers/char/tpm/tpm2-space.c | 48 +++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 59 insertions(+), 38 deletions(-) > > diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c > index ddaeceb..a1fda0d 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; > @@ -352,39 +343,20 @@ 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; > > if (!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 = tpm2_add_device(chip); > + if (rc) > + goto 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; > + > +del_cdev: > + cdev_device_del(&chip->cdev, &chip->dev); > return rc; > } > > @@ -640,8 +610,10 @@ void tpm_chip_unregister(struct tpm_chip *chip) > if (IS_ENABLED(CONFIG_HW_RANDOM_TPM)) > hwrng_unregister(&chip->hwrng); > tpm_bios_log_teardown(chip); > - if (chip->flags & TPM_CHIP_FLAG_TPM2) > + if (chip->flags & TPM_CHIP_FLAG_TPM2) { > cdev_device_del(&chip->cdevs, &chip->devs); > + put_device(&chip->devs); > + } > 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 947d1db..aa93af5 100644 > --- a/drivers/char/tpm/tpm.h > +++ b/drivers/char/tpm/tpm.h > @@ -238,6 +238,7 @@ 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 tpm2_add_device(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 784b8b3..96b2a4b 100644 > --- a/drivers/char/tpm/tpm2-space.c > +++ b/drivers/char/tpm/tpm2-space.c > @@ -571,3 +571,51 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, > dev_err(&chip->dev, "%s: error %d\n", __func__, rc); > return rc; > } > + > +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); > +} > + /* * Please describe what the heck the function does. No need for full on * kdoc. */ > +int tpm2_add_device(struct tpm_chip *chip) Please, rename as tpm_devs_add for coherency sake. > +{ > + int rc; > + > + device_initialize(&chip->devs); > + chip->devs.parent = chip->dev.parent; > + chip->devs.class = tpmrm_class; Empty line. Cannot recall, if I stated before. > + /* + * 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); NAK, same comment as before. > + 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 out_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 out_put_devs; > + } > + > + return 0; > + > +out_put_devs: > + put_device(&chip->devs); > + > + return rc; > +} > -- > 2.7.4 > /Jarkko
Hi, On 17.02.21 at 23:18, Jarkko Sakkinen wrote: >> + > > /* > * Please describe what the heck the function does. No need for full on > * kdoc. > */ Ok. >> +int tpm2_add_device(struct tpm_chip *chip) > > Please, rename as tpm_devs_add for coherency sake. > Sorry I confused this and renamed it wrongly. I will fix it in the next patch version. >> +{ >> + int rc; >> + >> + device_initialize(&chip->devs); >> + chip->devs.parent = chip->dev.parent; >> + chip->devs.class = tpmrm_class; > > Empty line. Cannot recall, if I stated before. >> + /* + * 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); > > NAK, same comment as before. > Thx for the review, I will fix these issues. Regards, Lino
On Thu, Feb 18, 2021 at 08:13:57PM +0100, Lino Sanfilippo wrote: > > Hi, > > On 17.02.21 at 23:18, Jarkko Sakkinen wrote: > > >> + > > > > /* > > * Please describe what the heck the function does. No need for full on > > * kdoc. > > */ > > Ok. > > >> +int tpm2_add_device(struct tpm_chip *chip) > > > > Please, rename as tpm_devs_add for coherency sake. > > > > Sorry I confused this and renamed it wrongly. I will fix it in the next > patch version. > > >> +{ > >> + int rc; > >> + > >> + device_initialize(&chip->devs); > >> + chip->devs.parent = chip->dev.parent; > >> + chip->devs.class = tpmrm_class; > > > > Empty line. Cannot recall, if I stated before. > >> + /* + * 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); > > > > NAK, same comment as before. > > > > Thx for the review, I will fix these issues. Yeah, I mean I'm going to collect this fix anyway after rc1 has been released so there's a lot of time to polish small details. I.e. I'm doing a PR for rc2 with the fix included. > Regards, > Lino /Jarkko
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index ddaeceb..a1fda0d 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; @@ -352,39 +343,20 @@ 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; if (!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 = tpm2_add_device(chip); + if (rc) + goto 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; + +del_cdev: + cdev_device_del(&chip->cdev, &chip->dev); return rc; } @@ -640,8 +610,10 @@ void tpm_chip_unregister(struct tpm_chip *chip) if (IS_ENABLED(CONFIG_HW_RANDOM_TPM)) hwrng_unregister(&chip->hwrng); tpm_bios_log_teardown(chip); - if (chip->flags & TPM_CHIP_FLAG_TPM2) + if (chip->flags & TPM_CHIP_FLAG_TPM2) { cdev_device_del(&chip->cdevs, &chip->devs); + put_device(&chip->devs); + } 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 947d1db..aa93af5 100644 --- a/drivers/char/tpm/tpm.h +++ b/drivers/char/tpm/tpm.h @@ -238,6 +238,7 @@ 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 tpm2_add_device(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 784b8b3..96b2a4b 100644 --- a/drivers/char/tpm/tpm2-space.c +++ b/drivers/char/tpm/tpm2-space.c @@ -571,3 +571,51 @@ int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, dev_err(&chip->dev, "%s: error %d\n", __func__, rc); return rc; } + +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); +} + +int tpm2_add_device(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 out_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 out_put_devs; + } + + return 0; + +out_put_devs: + put_device(&chip->devs); + + return rc; +}