TPM: Call tpm_transmit with correct size

commit 6b07d30aca7e52f2881b8c8c20c8a2cd28e8b3d3 upstream.

This patch changes the call of tpm_transmit by supplying the size of the
userspace buffer instead of TPM_BUFSIZE.

This got assigned CVE-2011-1161.

[The first hunk didn't make sense given one could expect
 way less data than TPM_BUFSIZE, so added tpm_transmit boundary
 check over bufsiz instead
 The last parameter of tpm_transmit() reflects the amount
 of data expected from the device, and not the buffer size
 being supplied to it. It isn't ideal to parse it directly,
 so we just set it to the maximum the input buffer can handle
 and let the userspace API to do such job.]

Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index edd7b7f3b26bd2774f05145941b60ec00c48013e..78cb0b3a96d30babe94340aaef14c44e1c04fa43 100644 (file)
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -374,6 +374,9 @@ static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
        u32 count, ordinal;
        unsigned long stop;
 
+       if (bufsiz > TPM_BUFSIZE)
+               bufsiz = TPM_BUFSIZE;
+
        count = be32_to_cpu(*((__be32 *) (buf + 2)));
        ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
        if (count == 0)