| Message ID | 20220525125904.483075-1-stefanb@linux.ibm.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] hw/tpm/tpm_tis_common.c: Assert that locty is in range | expand |
On Wed, May 25, 2022 at 3:02 PM Stefan Berger <stefanb@linux.ibm.com> wrote: > From: Peter Maydell <peter.maydell@linaro.org> > > In tpm_tis_mmio_read(), tpm_tis_mmio_write() and > tpm_tis_dump_state(), we calculate a locality index with > tpm_tis_locality_from_addr() and then use it as an index into the > s->loc[] array. In all these cases, the array index can't overflow > because the MemoryRegion is sized to be TPM_TIS_NUM_LOCALITIES << > TPM_TIS_LOCALITY_SHIFT bytes. However, Coverity can't see that, and > it complains (CID 1487138, 1487180, 1487188, 1487198, 1487240). > > Add an assertion to tpm_tis_locality_from_addr() that the calculated > locality index is valid, which will help Coverity and also catch any > potential future bug where the MemoryRegion isn't sized exactly. > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> > Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> > > --- > > v2: > - Moved 3 asserts from 3 callsites of tpm_tis_locality_from_addr() into > tpm_tis_locality_from_addr() > --- > hw/tpm/tpm_tis_common.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/hw/tpm/tpm_tis_common.c b/hw/tpm/tpm_tis_common.c > index e700d82181..503be2a541 100644 > --- a/hw/tpm/tpm_tis_common.c > +++ b/hw/tpm/tpm_tis_common.c > @@ -50,7 +50,12 @@ static uint64_t tpm_tis_mmio_read(void *opaque, hwaddr > addr, > > static uint8_t tpm_tis_locality_from_addr(hwaddr addr) > { > - return (uint8_t)((addr >> TPM_TIS_LOCALITY_SHIFT) & 0x7); > + uint8_t locty; > + > + locty = (uint8_t)((addr >> TPM_TIS_LOCALITY_SHIFT) & 0x7); > + assert(TPM_TIS_IS_VALID_LOCTY(locty)); > + > + return locty; > } > > > -- > 2.36.1 > > >
diff --git a/hw/tpm/tpm_tis_common.c b/hw/tpm/tpm_tis_common.c index e700d82181..503be2a541 100644 --- a/hw/tpm/tpm_tis_common.c +++ b/hw/tpm/tpm_tis_common.c @@ -50,7 +50,12 @@ static uint64_t tpm_tis_mmio_read(void *opaque, hwaddr addr, static uint8_t tpm_tis_locality_from_addr(hwaddr addr) { - return (uint8_t)((addr >> TPM_TIS_LOCALITY_SHIFT) & 0x7); + uint8_t locty; + + locty = (uint8_t)((addr >> TPM_TIS_LOCALITY_SHIFT) & 0x7); + assert(TPM_TIS_IS_VALID_LOCTY(locty)); + + return locty; }