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Avoid passing out-of-bound pointers to 0-size memcpy #879

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Merged
merged 1 commit into from
Jun 16, 2021
Merged

Avoid passing out-of-bound pointers to 0-size memcpy #879

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4 changes: 2 additions & 2 deletions contrib/lax_der_parsing.c
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Original file line number Diff line number Diff line change
Expand Up @@ -121,7 +121,7 @@ int ecdsa_signature_parse_der_lax(const secp256k1_context* ctx, secp256k1_ecdsa_
/* Copy R value */
if (rlen > 32) {
overflow = 1;
} else {
} else if (rlen) {
memcpy(tmpsig + 32 - rlen, input + rpos, rlen);
}

Expand All @@ -133,7 +133,7 @@ int ecdsa_signature_parse_der_lax(const secp256k1_context* ctx, secp256k1_ecdsa_
/* Copy S value */
if (slen > 32) {
overflow = 1;
} else {
} else if (slen) {
memcpy(tmpsig + 64 - slen, input + spos, slen);
}

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2 changes: 1 addition & 1 deletion contrib/lax_der_privatekey_parsing.c
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Expand Up @@ -45,7 +45,7 @@ int ec_privkey_import_der(const secp256k1_context* ctx, unsigned char *out32, co
if (end < privkey+2 || privkey[0] != 0x04 || privkey[1] > 0x20 || end < privkey+2+privkey[1]) {
return 0;
}
memcpy(out32 + 32 - privkey[1], privkey + 2, privkey[1]);
if (privkey[1]) memcpy(out32 + 32 - privkey[1], privkey + 2, privkey[1]);
if (!secp256k1_ec_seckey_verify(ctx, out32)) {
memset(out32, 0, 32);
return 0;
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2 changes: 1 addition & 1 deletion src/ecdsa_impl.h
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Expand Up @@ -140,7 +140,7 @@ static int secp256k1_der_parse_integer(secp256k1_scalar *r, const unsigned char
overflow = 1;
}
if (!overflow) {
memcpy(ra + 32 - rlen, *sig, rlen);
if (rlen) memcpy(ra + 32 - rlen, *sig, rlen);
secp256k1_scalar_set_b32(r, ra, &overflow);
}
if (overflow) {
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