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authorTadeusz Struk <tadeusz.struk@intel.com>2018-05-22 14:37:18 -0700
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2018-05-30 20:11:31 +0300
commit3ab2011ea368ec3433ad49e1b9e1c7b70d2e65df (patch)
tree83807afb8ea61e77a8d2a2ed698e0c7615390938 /drivers/char/tpm/tpm-dev.h
parent424eaf910c329ab06ad03a527ef45dcf6a328f00 (diff)
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tpm: fix race condition in tpm_common_write()
There is a race condition in tpm_common_write function allowing two threads on the same /dev/tpm<N>, or two different applications on the same /dev/tpmrm<N> to overwrite each other commands/responses. Fixed this by taking the priv->buffer_mutex early in the function. Also converted the priv->data_pending from atomic to a regular size_t type. There is no need for it to be atomic since it is only touched under the protection of the priv->buffer_mutex. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Diffstat (limited to 'drivers/char/tpm/tpm-dev.h')
-rw-r--r--drivers/char/tpm/tpm-dev.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/char/tpm/tpm-dev.h b/drivers/char/tpm/tpm-dev.h
index ba3b6f9dacf7..b24cfb4d3ee1 100644
--- a/drivers/char/tpm/tpm-dev.h
+++ b/drivers/char/tpm/tpm-dev.h
@@ -8,7 +8,7 @@ struct file_priv {
struct tpm_chip *chip;
/* Data passed to and from the tpm via the read/write calls */
- atomic_t data_pending;
+ size_t data_pending;
struct mutex buffer_mutex;
struct timer_list user_read_timer; /* user needs to claim result */