* [PATCH v4] TPM fixes @ 2021-02-16 0:30 Lino Sanfilippo 2021-02-16 0:31 ` [PATCH v4] tpm: fix reference counting for struct tpm_chip Lino Sanfilippo 0 siblings, 1 reply; 16+ messages in thread From: Lino Sanfilippo @ 2021-02-16 0:30 UTC (permalink / raw) To: peterhuewe, jarkko, jgg Cc: stefanb, James.Bottomley, linux-integrity, linux-kernel, LinoSanfilippo This patch fixes a reference count issue in the TPM core code. It is based on a suggestion and basic implementation made by Jason Gunthorpe. Changes in v4: - drop patch 2 (tpm: in tpm2_del_space check if ops pointer is still valid) since James Bottomley offered a cleaner solution for this - reimplement patch 1 to setup the /dev/tpmrm device only in case of TPM2 and avoid the installation of another action handler - add proper tag for stable Changes in v3: - drop the patch that introduces the new function tpm_chip_free() - rework the commit messages for the patches (style, typos, etc.) - add fixes tag to patch 2 - add James Bottomley to cc list - add stable mailing list to cc list Changes in v2: - drop the patch that erroneously cleaned up after failed installation of an action handler in tpmm_chip_alloc() (pointed out by Jarkko Sakkinen) - make the commit message for patch 1 more detailed - add fixes tags and kernel logs Lino Sanfilippo (1): tpm: fix reference counting for struct tpm_chip drivers/char/tpm/tpm-chip.c | 80 ++++++++++++++++++++++++++++----------------- 1 file changed, 50 insertions(+), 30 deletions(-) -- 2.7.4 ^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 0:30 [PATCH v4] TPM fixes Lino Sanfilippo @ 2021-02-16 0:31 ` Lino Sanfilippo 2021-02-16 8:27 ` Jarkko Sakkinen ` (2 more replies) 0 siblings, 3 replies; 16+ messages in thread From: Lino Sanfilippo @ 2021-02-16 0:31 UTC (permalink / raw) To: peterhuewe, jarkko, jgg Cc: stefanb, James.Bottomley, linux-integrity, linux-kernel, LinoSanfilippo, Lino Sanfilippo, stable 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 implemenation 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. 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> Cc: stable@vger.kernel.org --- drivers/char/tpm/tpm-chip.c | 80 ++++++++++++++++++++++++++++----------------- 1 file changed, 50 insertions(+), 30 deletions(-) diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index ddaeceb..44cac3a 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -344,7 +344,6 @@ 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 +351,20 @@ 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 +376,6 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev, return chip; out: - put_device(&chip->devs); put_device(&chip->dev); return ERR_PTR(rc); } @@ -431,6 +410,46 @@ struct tpm_chip *tpmm_chip_alloc(struct device *pdev, } EXPORT_SYMBOL_GPL(tpmm_chip_alloc); +static int tpm_add_tpm2_char_device(struct tpm_chip *chip) +{ + int rc; + + device_initialize(&chip->devs); + chip->devs.parent = chip->dev.parent; + chip->devs.class = tpmrm_class; + + rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num); + if (rc) + goto out_put_devs; + /* + * 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 = 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; +} + static int tpm_add_char_device(struct tpm_chip *chip) { int rc; @@ -445,14 +464,9 @@ 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_add_tpm2_char_device(chip); + if (rc) + goto del_cdev; } /* Make the chip available. */ @@ -460,6 +474,10 @@ 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 +658,10 @@ 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); -- 2.7.4 ^ permalink raw reply related [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 0:31 ` [PATCH v4] tpm: fix reference counting for struct tpm_chip Lino Sanfilippo @ 2021-02-16 8:27 ` Jarkko Sakkinen 2021-02-16 12:53 ` Jason Gunthorpe 2021-02-16 16:52 ` Stefan Berger 2 siblings, 0 replies; 16+ messages in thread From: Jarkko Sakkinen @ 2021-02-16 8:27 UTC (permalink / raw) To: Lino Sanfilippo Cc: peterhuewe, jgg, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable On Tue, Feb 16, 2021 at 01:31:00AM +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 Add '.' to end. > 2. Remove module tpm_tis_spi Add '.' to end. > 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 implemenation 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. > > 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> > Cc: stable@vger.kernel.org Put Cc first. > --- > drivers/char/tpm/tpm-chip.c | 80 ++++++++++++++++++++++++++++----------------- > 1 file changed, 50 insertions(+), 30 deletions(-) > > diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c > index ddaeceb..44cac3a 100644 > --- a/drivers/char/tpm/tpm-chip.c > +++ b/drivers/char/tpm/tpm-chip.c > @@ -344,7 +344,6 @@ 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 +351,20 @@ 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 +376,6 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev, > return chip; > > out: > - put_device(&chip->devs); > put_device(&chip->dev); > return ERR_PTR(rc); > } > @@ -431,6 +410,46 @@ struct tpm_chip *tpmm_chip_alloc(struct device *pdev, > } > EXPORT_SYMBOL_GPL(tpmm_chip_alloc); > > +static int tpm_add_tpm2_char_device(struct tpm_chip *chip) > +{ > + int rc; > + > + device_initialize(&chip->devs); > + chip->devs.parent = chip->dev.parent; > + chip->devs.class = tpmrm_class; > + > + rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num); > + if (rc) > + goto out_put_devs; > + /* > + * 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 = 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; > +} > + > static int tpm_add_char_device(struct tpm_chip *chip) > { > int rc; > @@ -445,14 +464,9 @@ 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_add_tpm2_char_device(chip); > + if (rc) > + goto del_cdev; > } > > /* Make the chip available. */ > @@ -460,6 +474,10 @@ 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 +658,10 @@ 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); > -- > 2.7.4 > Other than that, this looks good to me. If this passes testing, I can fix those nit's. I'll test this post 5.12 PR. /Jarkko ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 0:31 ` [PATCH v4] tpm: fix reference counting for struct tpm_chip Lino Sanfilippo 2021-02-16 8:27 ` Jarkko Sakkinen @ 2021-02-16 12:53 ` Jason Gunthorpe 2021-02-16 16:04 ` Jarkko Sakkinen 2021-02-16 19:04 ` Lino Sanfilippo 2021-02-16 16:52 ` Stefan Berger 2 siblings, 2 replies; 16+ messages in thread From: Jason Gunthorpe @ 2021-02-16 12:53 UTC (permalink / raw) To: Lino Sanfilippo Cc: peterhuewe, jarkko, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable On Tue, Feb 16, 2021 at 01:31:00AM +0100, Lino Sanfilippo wrote: > > +static int tpm_add_tpm2_char_device(struct tpm_chip *chip) > +{ > + int rc; > + > + device_initialize(&chip->devs); > + chip->devs.parent = chip->dev.parent; > + chip->devs.class = tpmrm_class; > + > + rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num); > + if (rc) > + goto out_put_devs; > + /* > + * 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 = 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); I'd rather you organize this so chip->devs.release and the get_device is always sent instead of having the possiblity for a put_device that doesn't call release Jason ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 12:53 ` Jason Gunthorpe @ 2021-02-16 16:04 ` Jarkko Sakkinen 2021-02-16 16:09 ` Jarkko Sakkinen ` (2 more replies) 2021-02-16 19:04 ` Lino Sanfilippo 1 sibling, 3 replies; 16+ messages in thread From: Jarkko Sakkinen @ 2021-02-16 16:04 UTC (permalink / raw) To: Jason Gunthorpe Cc: Lino Sanfilippo, peterhuewe, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable On Tue, Feb 16, 2021 at 08:53:42AM -0400, Jason Gunthorpe wrote: > On Tue, Feb 16, 2021 at 01:31:00AM +0100, Lino Sanfilippo wrote: > > > > +static int tpm_add_tpm2_char_device(struct tpm_chip *chip) BTW, this naming is crap. - 2x tpm - char is useless -> tpm2_add_device > > +{ > > + int rc; > > + > > + device_initialize(&chip->devs); > > + chip->devs.parent = chip->dev.parent; > > + chip->devs.class = tpmrm_class; > > + > > + rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num); > > + if (rc) > > + goto out_put_devs; Right, and empty line missing here. > > + /* > > + * 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); Isn't this less than 100 chars? > > + cdev_init(&chip->cdevs, &tpmrm_fops); > > + chip->cdevs.owner = THIS_MODULE; > > + > > + 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); > > I'd rather you organize this so chip->devs.release and the get_device > is always sent instead of having the possiblity for a put_device that > doesn't call release /Jarkko ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 16:04 ` Jarkko Sakkinen @ 2021-02-16 16:09 ` Jarkko Sakkinen 2021-02-16 16:11 ` Jarkko Sakkinen 2021-02-16 16:31 ` David Laight 2021-02-16 19:15 ` Lino Sanfilippo 2 siblings, 1 reply; 16+ messages in thread From: Jarkko Sakkinen @ 2021-02-16 16:09 UTC (permalink / raw) To: Jason Gunthorpe Cc: Lino Sanfilippo, peterhuewe, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable On Tue, Feb 16, 2021 at 06:04:42PM +0200, Jarkko Sakkinen wrote: > On Tue, Feb 16, 2021 at 08:53:42AM -0400, Jason Gunthorpe wrote: > > On Tue, Feb 16, 2021 at 01:31:00AM +0100, Lino Sanfilippo wrote: > > > > > > +static int tpm_add_tpm2_char_device(struct tpm_chip *chip) > > BTW, this naming is crap. > > - 2x tpm > - char is useless > > -> tpm2_add_device Actually, tpm2s_add_device() add put it to tpm2-space.c. > > > +{ > > > + int rc; > > > + > > > + device_initialize(&chip->devs); > > > + chip->devs.parent = chip->dev.parent; > > > + chip->devs.class = tpmrm_class; > > > + > > > + rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num); > > > + if (rc) > > > + goto out_put_devs; > > Right, and empty line missing here. > > > > + /* > > > + * 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); > > Isn't this less than 100 chars? > > > > + cdev_init(&chip->cdevs, &tpmrm_fops); > > > + chip->cdevs.owner = THIS_MODULE; > > > + > > > + 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); > > > > I'd rather you organize this so chip->devs.release and the get_device > > is always sent instead of having the possiblity for a put_device that > > doesn't call release > > /Jarkko ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 16:09 ` Jarkko Sakkinen @ 2021-02-16 16:11 ` Jarkko Sakkinen 2021-02-16 19:08 ` Lino Sanfilippo 0 siblings, 1 reply; 16+ messages in thread From: Jarkko Sakkinen @ 2021-02-16 16:11 UTC (permalink / raw) To: Jason Gunthorpe Cc: Lino Sanfilippo, peterhuewe, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable On Tue, Feb 16, 2021 at 06:09:50PM +0200, Jarkko Sakkinen wrote: > On Tue, Feb 16, 2021 at 06:04:42PM +0200, Jarkko Sakkinen wrote: > > On Tue, Feb 16, 2021 at 08:53:42AM -0400, Jason Gunthorpe wrote: > > > On Tue, Feb 16, 2021 at 01:31:00AM +0100, Lino Sanfilippo wrote: > > > > > > > > +static int tpm_add_tpm2_char_device(struct tpm_chip *chip) > > > > BTW, this naming is crap. > > > > - 2x tpm > > - char is useless > > > > -> tpm2_add_device > > Actually, tpm2s_add_device() add put it to tpm2-space.c. No, tpms_add_device() :-) (sorry) /Jarkko > > > > > +{ > > > > + int rc; > > > > + > > > > + device_initialize(&chip->devs); > > > > + chip->devs.parent = chip->dev.parent; > > > > + chip->devs.class = tpmrm_class; > > > > + > > > > + rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num); > > > > + if (rc) > > > > + goto out_put_devs; > > > > Right, and empty line missing here. > > > > > > + /* > > > > + * 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); > > > > Isn't this less than 100 chars? > > > > > > + cdev_init(&chip->cdevs, &tpmrm_fops); > > > > + chip->cdevs.owner = THIS_MODULE; > > > > + > > > > + 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); > > > > > > I'd rather you organize this so chip->devs.release and the get_device > > > is always sent instead of having the possiblity for a put_device that > > > doesn't call release > > > > /Jarkko ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 16:11 ` Jarkko Sakkinen @ 2021-02-16 19:08 ` Lino Sanfilippo 0 siblings, 0 replies; 16+ messages in thread From: Lino Sanfilippo @ 2021-02-16 19:08 UTC (permalink / raw) To: Jarkko Sakkinen, Jason Gunthorpe Cc: peterhuewe, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable Hi, On 16.02.21 at 17:11, Jarkko Sakkinen wrote: > On Tue, Feb 16, 2021 at 06:09:50PM +0200, Jarkko Sakkinen wrote: >> On Tue, Feb 16, 2021 at 06:04:42PM +0200, Jarkko Sakkinen wrote: >>> On Tue, Feb 16, 2021 at 08:53:42AM -0400, Jason Gunthorpe wrote: >>>> On Tue, Feb 16, 2021 at 01:31:00AM +0100, Lino Sanfilippo wrote: >>>>> >>>>> +static int tpm_add_tpm2_char_device(struct tpm_chip *chip) >>> >>> BTW, this naming is crap. >>> >>> - 2x tpm >>> - char is useless >>> >>> -> tpm2_add_device >> >> Actually, tpm2s_add_device() add put it to tpm2-space.c. > > No, tpms_add_device() :-) > > (sorry) > > /Jarkko > I strongly assume you mean tmp2_add_device() :) I will move and rename the function accordingly. Thanks, Lino ^ permalink raw reply [flat|nested] 16+ messages in thread
* RE: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 16:04 ` Jarkko Sakkinen 2021-02-16 16:09 ` Jarkko Sakkinen @ 2021-02-16 16:31 ` David Laight 2021-02-17 22:14 ` Jarkko Sakkinen 2021-02-16 19:15 ` Lino Sanfilippo 2 siblings, 1 reply; 16+ messages in thread From: David Laight @ 2021-02-16 16:31 UTC (permalink / raw) To: 'Jarkko Sakkinen', Jason Gunthorpe Cc: Lino Sanfilippo, peterhuewe, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable ... > > > + get_device(&chip->dev); > > > + chip->devs.release = tpm_devs_release; > > > + chip->devs.devt = > > > + MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES); > > Isn't this less than 100 chars? Still best kept under 80 if 'reasonable'? Really it is just split in the wrong place: chip->devs.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES); David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 16:31 ` David Laight @ 2021-02-17 22:14 ` Jarkko Sakkinen 2021-02-18 1:27 ` Jason Gunthorpe 0 siblings, 1 reply; 16+ messages in thread From: Jarkko Sakkinen @ 2021-02-17 22:14 UTC (permalink / raw) To: David Laight Cc: Jason Gunthorpe, Lino Sanfilippo, peterhuewe, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable On Tue, Feb 16, 2021 at 04:31:26PM +0000, David Laight wrote: > ... > > > > + get_device(&chip->dev); > > > > + chip->devs.release = tpm_devs_release; > > > > + chip->devs.devt = > > > > + MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES); > > > > Isn't this less than 100 chars? > > Still best kept under 80 if 'reasonable'? > > Really it is just split in the wrong place: > chip->devs.devt = MKDEV(MAJOR(tpm_devt), > chip->dev_num + TPM_NUM_DEVICES); Well it looks crap IMHO. Would be more reasonable to have it in a single like. And it is legit too, since it is accepted by checkpatch. You might break the lines within 80 chars if it is somehow "logically" consistent. > > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales) > > /Jarkko ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-17 22:14 ` Jarkko Sakkinen @ 2021-02-18 1:27 ` Jason Gunthorpe 2021-02-19 7:07 ` Jarkko Sakkinen 0 siblings, 1 reply; 16+ messages in thread From: Jason Gunthorpe @ 2021-02-18 1:27 UTC (permalink / raw) To: Jarkko Sakkinen Cc: David Laight, Lino Sanfilippo, peterhuewe, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo On Thu, Feb 18, 2021 at 12:14:11AM +0200, Jarkko Sakkinen wrote: > On Tue, Feb 16, 2021 at 04:31:26PM +0000, David Laight wrote: > > ... > > > > > + get_device(&chip->dev); > > > > > + chip->devs.release = tpm_devs_release; > > > > > + chip->devs.devt = > > > > > + MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES); > > > > > > Isn't this less than 100 chars? > > > > Still best kept under 80 if 'reasonable'? > > > > Really it is just split in the wrong place: > > chip->devs.devt = MKDEV(MAJOR(tpm_devt), > > chip->dev_num + TPM_NUM_DEVICES); > > > Well it looks crap IMHO. Would be more reasonable to have it in a single > like. And it is legit too, since it is accepted by checkpatch. > > You might break the lines within 80 chars if it is somehow "logically" > consistent. FWIW, I've become kind of tired of the style wishywashyness I've mostly been happy to accept anything that clang-format spits out for ordinary C constructs. It is good enough and universally usable. If devs don't have it linked to their editor to format single expression or format selected blocks, they are missing out :) The community consensus on style is quite unclear. Is 1 or 2 above the majority preference? Does this case fall under the new "use more than 80 cols if it improves readability?" I have no idea. Frankly, for most people writing driver code, if they consistently use clang-format their work will be alot better than if they try to do it by hand. It takes a lot of experiance to reliably eyeball something close to the kernel style.. Jason ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-18 1:27 ` Jason Gunthorpe @ 2021-02-19 7:07 ` Jarkko Sakkinen 0 siblings, 0 replies; 16+ messages in thread From: Jarkko Sakkinen @ 2021-02-19 7:07 UTC (permalink / raw) To: Jason Gunthorpe Cc: David Laight, Lino Sanfilippo, peterhuewe, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo On Wed, Feb 17, 2021 at 09:27:02PM -0400, Jason Gunthorpe wrote: > On Thu, Feb 18, 2021 at 12:14:11AM +0200, Jarkko Sakkinen wrote: > > On Tue, Feb 16, 2021 at 04:31:26PM +0000, David Laight wrote: > > > ... > > > > > > + get_device(&chip->dev); > > > > > > + chip->devs.release = tpm_devs_release; > > > > > > + chip->devs.devt = > > > > > > + MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES); > > > > > > > > Isn't this less than 100 chars? > > > > > > Still best kept under 80 if 'reasonable'? > > > > > > Really it is just split in the wrong place: > > > chip->devs.devt = MKDEV(MAJOR(tpm_devt), > > > chip->dev_num + TPM_NUM_DEVICES); > > > > > > Well it looks crap IMHO. Would be more reasonable to have it in a single > > like. And it is legit too, since it is accepted by checkpatch. > > > > You might break the lines within 80 chars if it is somehow "logically" > > consistent. > > FWIW, I've become kind of tired of the style wishywashyness I've > mostly been happy to accept anything that clang-format spits out for > ordinary C constructs. A. I would not mind if it was already merged. Since it isn't, I don't see the point not fixing it. > It is good enough and universally usable. If devs don't have it linked > to their editor to format single expression or format selected blocks, > they are missing out :) > > The community consensus on style is quite unclear. Is 1 or 2 above the > majority preference? Does this case fall under the new "use more than > 80 cols if it improves readability?" I have no idea. B. I need to maintain this, once it's merged. C. A smaller diff for a critical bug fix. I actually allow style compromises for fixes to be backported *when* it makes the overall diff smaller. D. Has more odds to make future changes smaller as the whole thing is in a single code line. > Frankly, for most people writing driver code, if they consistently use > clang-format their work will be alot better than if they try to do it > by hand. It takes a lot of experiance to reliably eyeball something > close to the kernel style.. For me it gives a framework to review patches in multiple subsystems. If I have to constantly think whether to allow this and that shift from the kernel coding style, it makes the whole process for me more fuzzy and chaotic. As I said (A), it would not be end of the world if this had been merged already. I also want to state that I do sometimes make mistakes when reviewing code, and am happy to take critique from that :-) > Jason /Jarkko ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 16:04 ` Jarkko Sakkinen 2021-02-16 16:09 ` Jarkko Sakkinen 2021-02-16 16:31 ` David Laight @ 2021-02-16 19:15 ` Lino Sanfilippo 2 siblings, 0 replies; 16+ messages in thread From: Lino Sanfilippo @ 2021-02-16 19:15 UTC (permalink / raw) To: Jarkko Sakkinen, Jason Gunthorpe Cc: peterhuewe, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable, David Laight Hi On 16.02.21 at 17:04, Jarkko Sakkinen wrote: >>> + /* >>> + * 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); > > Isn't this less than 100 chars? > I just chose the same formatting that the original code used. Personally I prefer what David suggested, so if there is no objection against it I will format it this way. Regards, Lino ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 12:53 ` Jason Gunthorpe 2021-02-16 16:04 ` Jarkko Sakkinen @ 2021-02-16 19:04 ` Lino Sanfilippo 1 sibling, 0 replies; 16+ messages in thread From: Lino Sanfilippo @ 2021-02-16 19:04 UTC (permalink / raw) To: Jason Gunthorpe Cc: peterhuewe, jarkko, stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable Hi, On 16.02.21 at 13:53, Jason Gunthorpe wrote: > On Tue, Feb 16, 2021 at 01:31:00AM +0100, Lino Sanfilippo wrote: >> >> +static int tpm_add_tpm2_char_device(struct tpm_chip *chip) >> +{ >> + int rc; >> + >> + device_initialize(&chip->devs); >> + chip->devs.parent = chip->dev.parent; >> + chip->devs.class = tpmrm_class; >> + >> + rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num); >> + if (rc) >> + goto out_put_devs; >> + /* >> + * 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 = 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); > > I'd rather you organize this so chip->devs.release and the get_device > is always sent instead of having the possiblity for a put_device that > doesn't call release > Agreed, I will change it. It should not make a difference in terms of correctness but I see that it is less confusing if both error cases are handled similarly (plus its only a minimal change). Best regards, Lino ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 0:31 ` [PATCH v4] tpm: fix reference counting for struct tpm_chip Lino Sanfilippo 2021-02-16 8:27 ` Jarkko Sakkinen 2021-02-16 12:53 ` Jason Gunthorpe @ 2021-02-16 16:52 ` Stefan Berger 2021-02-16 19:17 ` Lino Sanfilippo 2 siblings, 1 reply; 16+ messages in thread From: Stefan Berger @ 2021-02-16 16:52 UTC (permalink / raw) To: Lino Sanfilippo, peterhuewe, jarkko, jgg Cc: stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable On 2/15/21 7:31 PM, 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 implemenation 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. > > 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> > Cc: stable@vger.kernel.org I know you'll post another version, but anyway: Tested-by: Stefan Berger <stefanb@linux.ibm.com> ^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v4] tpm: fix reference counting for struct tpm_chip 2021-02-16 16:52 ` Stefan Berger @ 2021-02-16 19:17 ` Lino Sanfilippo 0 siblings, 0 replies; 16+ messages in thread From: Lino Sanfilippo @ 2021-02-16 19:17 UTC (permalink / raw) To: Stefan Berger, peterhuewe, jarkko, jgg Cc: stefanb, James.Bottomley, linux-integrity, linux-kernel, Lino Sanfilippo, stable Hi Stefan, On 16.02.21 at 17:52, Stefan Berger wrote: > On 2/15/21 7:31 PM, 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 implemenation 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. >> >> 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> >> Cc: stable@vger.kernel.org > > > I know you'll post another version, but anyway: > > Tested-by: Stefan Berger <stefanb@linux.ibm.com> Thank you for testing this, I will send a v5 shortly. Regards, Lino ^ permalink raw reply [flat|nested] 16+ messages in thread
end of thread, other threads:[~2021-02-19 7:08 UTC | newest] Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-02-16 0:30 [PATCH v4] TPM fixes Lino Sanfilippo 2021-02-16 0:31 ` [PATCH v4] tpm: fix reference counting for struct tpm_chip Lino Sanfilippo 2021-02-16 8:27 ` Jarkko Sakkinen 2021-02-16 12:53 ` Jason Gunthorpe 2021-02-16 16:04 ` Jarkko Sakkinen 2021-02-16 16:09 ` Jarkko Sakkinen 2021-02-16 16:11 ` Jarkko Sakkinen 2021-02-16 19:08 ` Lino Sanfilippo 2021-02-16 16:31 ` David Laight 2021-02-17 22:14 ` Jarkko Sakkinen 2021-02-18 1:27 ` Jason Gunthorpe 2021-02-19 7:07 ` Jarkko Sakkinen 2021-02-16 19:15 ` Lino Sanfilippo 2021-02-16 19:04 ` Lino Sanfilippo 2021-02-16 16:52 ` Stefan Berger 2021-02-16 19:17 ` Lino Sanfilippo
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