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authorJakob Unterwurzacher2021-09-07 17:47:48 +0200
committerJakob Unterwurzacher2021-09-07 18:15:04 +0200
commit3a80db953da93c741ad391ae124121459c1046b0 (patch)
treee8502cde88ac0bf0b2236a4c7da785d8be26089d /internal/stupidgcm/openssl.go
parent738d5a2b3a001318064be649d683684630eff4c2 (diff)
stupidgcm: allow zero-length input data
We used to panic in this case because it is useless. But Go stdlib supports it, so we should as well.
Diffstat (limited to 'internal/stupidgcm/openssl.go')
-rw-r--r--internal/stupidgcm/openssl.go21
1 files changed, 14 insertions, 7 deletions
diff --git a/internal/stupidgcm/openssl.go b/internal/stupidgcm/openssl.go
index 82ec0a1..ae0ee5c 100644
--- a/internal/stupidgcm/openssl.go
+++ b/internal/stupidgcm/openssl.go
@@ -20,9 +20,6 @@ func openSSLSeal(a *stupidAEADCommon, dst, iv, in, authData []byte) []byte {
if len(iv) != a.NonceSize() {
log.Panicf("Only %d-byte IVs are supported, you passed %d bytes", a.NonceSize(), len(iv))
}
- if len(in) == 0 {
- log.Panic("Zero-length input data is not supported")
- }
// If the "dst" slice is large enough we can use it as our output buffer
outLen := len(in) + tagLen
@@ -36,7 +33,7 @@ func openSSLSeal(a *stupidAEADCommon, dst, iv, in, authData []byte) []byte {
}
res := int(C.openssl_aead_seal(a.openSSLEVPCipher,
- (*C.uchar)(&in[0]),
+ slicePointerOrNull(in),
C.int(len(in)),
(*C.uchar)(&authData[0]),
C.int(len(authData)),
@@ -64,7 +61,7 @@ func openSSLOpen(a *stupidAEADCommon, dst, iv, in, authData []byte) ([]byte, err
if len(iv) != a.NonceSize() {
log.Panicf("Only %d-byte IVs are supported, you passed %d bytes", a.NonceSize(), len(iv))
}
- if len(in) <= tagLen {
+ if len(in) < tagLen {
return nil, fmt.Errorf("stupidChacha20poly1305: input data too short (%d bytes)", len(in))
}
@@ -83,7 +80,7 @@ func openSSLOpen(a *stupidAEADCommon, dst, iv, in, authData []byte) ([]byte, err
tag := in[len(in)-tagLen:]
res := int(C.openssl_aead_open(a.openSSLEVPCipher,
- (*C.uchar)(&ciphertext[0]),
+ slicePointerOrNull(ciphertext),
C.int(len(ciphertext)),
(*C.uchar)(&authData[0]),
C.int(len(authData)),
@@ -93,7 +90,7 @@ func openSSLOpen(a *stupidAEADCommon, dst, iv, in, authData []byte) ([]byte, err
C.int(len(a.key)),
(*C.uchar)(&iv[0]),
C.int(len(iv)),
- (*C.uchar)(&buf[0]),
+ slicePointerOrNull(buf),
C.int(len(buf))))
if res < 0 {
@@ -109,6 +106,16 @@ func openSSLOpen(a *stupidAEADCommon, dst, iv, in, authData []byte) ([]byte, err
return append(dst, buf...), nil
}
+// slicePointerOrNull returns a C pointer to the beginning of the byte slice,
+// or NULL if the byte slice is empty. This is useful for slices that can be
+// empty, otherwise you can directly use "(*C.uchar)(&s[0])".
+func slicePointerOrNull(s []byte) (ptr *C.uchar) {
+ if len(s) == 0 {
+ return
+ }
+ return (*C.uchar)(&s[0])
+}
+
// This functions exists to benchmark the C call overhead from Go.
// See BenchmarkCCall for resuts.
func noopCFunction() {