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Kees Cook authored
commit 782779b6 upstream. A "get random" may fail with a TPM error, but those codes were returned as-is to the caller, which assumed the result was the number of bytes that had been written to the target buffer, which could lead to a kernel heap memory exposure and over-read. This fixes tpm1_get_random() to mask positive TPM errors into -EIO, as before. [ 18.092103] tpm tpm0: A TPM error (379) occurred attempting get random [ 18.092106] usercopy: Kernel memory exposure attempt detected from SLUB object 'kmalloc-64' (offset 0, size 379)! Link: https://bugzilla.redhat.com/show_bug.cgi?id=1650989Reported-by:
Phil Baker <baker1tex@gmail.com> Reported-by:
Craig Robson <craig@zhatt.com> Fixes: 7aee9c52 ("tpm: tpm1: rewrite tpm1_get_random() using tpm_buf structure") Cc: Laura Abbott <labbott@redhat.com> Cc: Tomas Winkler <tomas.winkler@intel.com> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: stable@vger.kernel.org Signed-off-by:
Kees Cook <keescook@chromium.org> Reviewed-by:
Tomas Winkler <tomas.winkler@intel.com> Tested-by:
Bartosz Szczepanek <bsz@semihalf.com> Reviewed-by:
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by:
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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