tpm/tpm_i2c_stm_st33: Check return code of get_burstcount
authorPeter Huewe <PeterHuewe@gmx.de>
Tue, 29 Oct 2013 23:54:20 +0000 (00:54 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 6 Feb 2014 19:08:15 +0000 (11:08 -0800)
commit9bf4d6c3c302830f7d7ffec5f6f12948e2f53c9a
tree2667b550ddeb880bfa8bea9481b7aa85ba799d0e
parent3cf79a3cd9edc63a419ce3134ddc5b39575b0cdb
tpm/tpm_i2c_stm_st33: Check return code of get_burstcount

commit 85c5e0d451125c6ddb78663972e40af810b83644 upstream.

The 'get_burstcount' function can in some circumstances 'return -EBUSY' which
in tpm_stm_i2c_send is stored in an 'u32 burstcnt'
thus converting the signed value into an unsigned value, resulting
in 'burstcnt' being huge.
Changing the type to u32 only does not solve the problem as the signed
value is converted to an unsigned in I2C_WRITE_DATA, resulting in the
same effect.

Thus
-> Change type of burstcnt to u32 (the return type of get_burstcount)
-> Add a check for the return value of 'get_burstcount' and propagate a
potential error.

This makes also sense in the 'I2C_READ_DATA' case, where the there is no
signed/unsigned conversion.

found by coverity
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/char/tpm/tpm_i2c_stm_st33.c