frost/secp256k1-zkp
3
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Improve checks for scalar _get_bits methods

Browse Source
This commit is contained in:
Peter.Dettman
2026-04-12 17:37:42 +07:00
parent 7262adb4b4
commit 0cad3df503
3 changed files with 17 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
src/scalar_low_impl.h
View File

@@ -27,8 +27,10 @@ SECP256K1_INLINE static void secp256k1_scalar_set_int(secp256k1_scalar *r, unsig
SECP256K1_INLINE static uint32_t secp256k1_scalar_get_bits_limb32(const secp256k1_scalar *a, unsigned int offset, unsigned int count) {
SECP256K1_SCALAR_VERIFY(a);
VERIFY_CHECK(count > 0 && count <= 32);
VERIFY_CHECK(offset <= 256 - count);
VERIFY_CHECK((offset + count - 1) >> 5 == offset >> 5);
if (offset < 32) {
return (*a >> offset) & (0xFFFFFFFF >> (32 - count));
} else {
@@ -38,8 +40,14 @@ SECP256K1_INLINE static uint32_t secp256k1_scalar_get_bits_limb32(const secp256k
SECP256K1_INLINE static uint32_t secp256k1_scalar_get_bits_var(const secp256k1_scalar *a, unsigned int offset, unsigned int count) {
SECP256K1_SCALAR_VERIFY(a);
VERIFY_CHECK(count > 0 && count <= 32);
VERIFY_CHECK(offset <= 256 - count);
return secp256k1_scalar_get_bits_limb32(a, offset, count);
if (offset < 32) {
return (*a >> offset) & (0xFFFFFFFF >> (32 - count));
} else {
return 0;
}
}
SECP256K1_INLINE static int secp256k1_scalar_check_overflow(const secp256k1_scalar *a) { return *a >= EXHAUSTIVE_TEST_ORDER; }