Fix multiplication producing a negative zero
Fix mbedtls_mpi_mul_mpi() when one of the operands is zero and the
other is negative. The sign of the result must be 1, since some
library functions do not treat {-1, 0, NULL} or {-1, n, {0}} as
representing the value 0.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/suites/test_suite_mpi.data b/tests/suites/test_suite_mpi.data
index 630e008..cf62d88 100644
--- a/tests/suites/test_suite_mpi.data
+++ b/tests/suites/test_suite_mpi.data
@@ -904,6 +904,9 @@
Test mbedtls_mpi_mul_mpi: 0 (null) * -1
mbedtls_mpi_mul_mpi:16:"":16:"-01":16:""
+Test mbedtls_mpi_mul_mpi: 0 (1 limb) * -1
+mbedtls_mpi_mul_mpi:16:"00":16:"-01":16:""
+
Test mbedtls_mpi_mul_mpi: 0 (1 limb) * 0 (null)
mbedtls_mpi_mul_mpi:16:"":16:"00":16:""
@@ -913,6 +916,9 @@
Test mbedtls_mpi_mul_mpi: -1 * 0 (null)
mbedtls_mpi_mul_mpi:16:"-01":16:"":16:""
+Test mbedtls_mpi_mul_mpi: -1 * 0 (1 limb)
+mbedtls_mpi_mul_mpi:16:"-01":16:"00":16:""
+
Test mbedtls_mpi_mul_mpi #1
mbedtls_mpi_mul_mpi:10:"28911710017320205966167820725313234361535259163045867986277478145081076845846493521348693253530011243988160148063424837895971948244167867236923919506962312185829914482993478947657472351461336729641485069323635424692930278888923450060546465883490944265147851036817433970984747733020522259537":10:"16471581891701794764704009719057349996270239948993452268812975037240586099924712715366967486587417803753916334331355573776945238871512026832810626226164346328807407669366029926221415383560814338828449642265377822759768011406757061063524768140567867350208554439342320410551341675119078050953":10:"476221599179424887669515829231223263939342135681791605842540429321038144633323941248706405375723482912535192363845116154236465184147599697841273424891410002781967962186252583311115708128167171262206919514587899883547279647025952837516324649656913580411611297312678955801899536937577476819667861053063432906071315727948826276092545739432005962781562403795455162483159362585281248265005441715080197800335757871588045959754547836825977169125866324128449699877076762316768127816074587766799018626179199776188490087103869164122906791440101822594139648973454716256383294690817576188761"