commit 09cac24373e5a13cc527bf2f32132a9479d4ae1e Author: teor teor2345@gmail.com Date: Thu Dec 25 20:52:10 2014 +1100
Handle edge cases in the round_*_to_next_multiple_of functions
Consistently check for overflow in round_*_to_next_multiple_of.
Check all round_*_to_next_multiple_of functions with expected values. Check all round_*_to_next_multiple_of functions with maximal values.
Related to HS stats in #13192. --- changes/laplace-edge-cases | 6 +++++- src/common/util.c | 12 +++++++++--- src/test/test_util.c | 27 +++++++++++++++++++++++++-- 3 files changed, 39 insertions(+), 6 deletions(-)
diff --git a/changes/laplace-edge-cases b/changes/laplace-edge-cases index f8a36e1..266b119 100644 --- a/changes/laplace-edge-cases +++ b/changes/laplace-edge-cases @@ -3,5 +3,9 @@ * avoid division by zero * avoid taking the log of zero * silence clang type conversion warnings using round and trunc - - Add tests for laplace edge cases. + * consistently check for overflow in round_*_to_next_multiple_of + - Add tests for laplace edge cases: + * check add_laplace_noise with maximal values + * check round_*_to_next_multiple_of with additional values + * check round_*_to_next_multiple_of with maximal values Related to HS stats in #13192. diff --git a/src/common/util.c b/src/common/util.c index 52b3e04..3e680d2 100644 --- a/src/common/util.c +++ b/src/common/util.c @@ -491,7 +491,9 @@ round_to_power_of_2(uint64_t u64) unsigned round_to_next_multiple_of(unsigned number, unsigned divisor) { - number += divisor - 1; + tor_assert(divisor > 0); + if (UINT_MAX - divisor + 1 >= number) + number += divisor - 1; number -= number % divisor; return number; } @@ -501,7 +503,9 @@ round_to_next_multiple_of(unsigned number, unsigned divisor) uint32_t round_uint32_to_next_multiple_of(uint32_t number, uint32_t divisor) { - number += divisor - 1; + tor_assert(divisor > 0); + if (UINT32_MAX - divisor + 1 >= number) + number += divisor - 1; number -= number % divisor; return number; } @@ -511,7 +515,9 @@ round_uint32_to_next_multiple_of(uint32_t number, uint32_t divisor) uint64_t round_uint64_to_next_multiple_of(uint64_t number, uint64_t divisor) { - number += divisor - 1; + tor_assert(divisor > 0); + if (UINT64_MAX - divisor + 1 >= number) + number += divisor - 1; number -= number % divisor; return number; } diff --git a/src/test/test_util.c b/src/test/test_util.c index 940f9bd..74d7227 100644 --- a/src/test/test_util.c +++ b/src/test/test_util.c @@ -4054,8 +4054,11 @@ test_util_round_to_next_multiple_of(void *arg) tt_u64_op(round_uint64_to_next_multiple_of(99,7), ==, 105); tt_u64_op(round_uint64_to_next_multiple_of(99,9), ==, 99);
- tt_i64_op(round_int64_to_next_multiple_of(0,1), ==, 0); - tt_i64_op(round_int64_to_next_multiple_of(0,7), ==, 0); + tt_assert(round_uint64_to_next_multiple_of(UINT64_MAX,2) == + UINT64_MAX-UINT64_MAX%2); + + tt_assert(round_int64_to_next_multiple_of(0,1) == 0); + tt_assert(round_int64_to_next_multiple_of(0,7) == 0);
tt_i64_op(round_int64_to_next_multiple_of(99,1), ==, 99); tt_i64_op(round_int64_to_next_multiple_of(99,7), ==, 105); @@ -4068,6 +4071,26 @@ test_util_round_to_next_multiple_of(void *arg) tt_i64_op(round_int64_to_next_multiple_of(INT64_MIN,2), ==, INT64_MIN); tt_i64_op(round_int64_to_next_multiple_of(INT64_MAX,2), ==, INT64_MAX-INT64_MAX%2); + + tt_assert(round_uint32_to_next_multiple_of(0,1) == 0); + tt_assert(round_uint32_to_next_multiple_of(0,7) == 0); + + tt_assert(round_uint32_to_next_multiple_of(99,1) == 99); + tt_assert(round_uint32_to_next_multiple_of(99,7) == 105); + tt_assert(round_uint32_to_next_multiple_of(99,9) == 99); + + tt_assert(round_uint32_to_next_multiple_of(UINT32_MAX,2) == + UINT32_MAX-UINT32_MAX%2); + + tt_assert(round_to_next_multiple_of(0,1) == 0); + tt_assert(round_to_next_multiple_of(0,7) == 0); + + tt_assert(round_to_next_multiple_of(99,1) == 99); + tt_assert(round_to_next_multiple_of(99,7) == 105); + tt_assert(round_to_next_multiple_of(99,9) == 99); + + tt_assert(round_to_next_multiple_of(UINT_MAX,2) == + UINT_MAX-UINT_MAX%2); done: ; }