Mind the end of the buffer in aligned case of generic RC4 implementation.
The generic RC4 implementation may read and write just past the end of the
buffer; when input and output are aligned, it always reads an RC4_CHUNK at a
time. It appropriately masks off and preserves the excess bytes off the end, so
this can only have practical effects if it crosses a page boundary. There's an
alignment check, so that can't happen; page boundaries are always aligned. But
it makes ASan unhappy and strictly speaking is a memory error.
Instead, fall through to the generic codepath which just reads it byte by byte.
This should fix the other bot failure.
Change-Id: I3cbd3bfc6cb0537e87f3252dea12d40ffa78d590
Reviewed-on: https://boringssl-review.googlesource.com/4722
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/rc4/rc4.c b/crypto/rc4/rc4.c
index 2a98fd0..aa19dc2 100644
--- a/crypto/rc4/rc4.c
+++ b/crypto/rc4/rc4.c
@@ -141,37 +141,6 @@
in += sizeof(RC4_CHUNK);
out += sizeof(RC4_CHUNK);
}
- if (len) {
- RC4_CHUNK mask = (RC4_CHUNK) - 1, ochunk;
-
- ichunk = *(RC4_CHUNK *)in;
- ochunk = *(RC4_CHUNK *)out;
- otp = 0;
- i = BESHFT(0);
- mask <<= (sizeof(RC4_CHUNK) - len) << 3;
- switch (len & (sizeof(RC4_CHUNK) - 1)) {
- case 7:
- otp = RC4_STEP << i, i -= 8;
- case 6:
- otp |= RC4_STEP << i, i -= 8;
- case 5:
- otp |= RC4_STEP << i, i -= 8;
- case 4:
- otp |= RC4_STEP << i, i -= 8;
- case 3:
- otp |= RC4_STEP << i, i -= 8;
- case 2:
- otp |= RC4_STEP << i, i -= 8;
- case 1:
- otp |= RC4_STEP << i, i -= 8;
- }
- ochunk &= ~mask;
- ochunk |= (otp ^ ichunk) & mask;
- *(RC4_CHUNK *)out = ochunk;
- }
- key->x = x;
- key->y = y;
- return;
} else { /* LITTLE-ENDIAN CASE */
#define LESHFT(c) (((c) * 8) & (sizeof(RC4_CHUNK) * 8 - 1))
for (; len & (0 - sizeof(RC4_CHUNK)); len -= sizeof(RC4_CHUNK)) {
@@ -190,37 +159,6 @@
in += sizeof(RC4_CHUNK);
out += sizeof(RC4_CHUNK);
}
- if (len) {
- RC4_CHUNK mask = (RC4_CHUNK) - 1, ochunk;
-
- ichunk = *(RC4_CHUNK *)in;
- ochunk = *(RC4_CHUNK *)out;
- otp = 0;
- i = 0;
- mask >>= (sizeof(RC4_CHUNK) - len) << 3;
- switch (len & (sizeof(RC4_CHUNK) - 1)) {
- case 7:
- otp = RC4_STEP, i += 8;
- case 6:
- otp |= RC4_STEP << i, i += 8;
- case 5:
- otp |= RC4_STEP << i, i += 8;
- case 4:
- otp |= RC4_STEP << i, i += 8;
- case 3:
- otp |= RC4_STEP << i, i += 8;
- case 2:
- otp |= RC4_STEP << i, i += 8;
- case 1:
- otp |= RC4_STEP << i, i += 8;
- }
- ochunk &= ~mask;
- ochunk |= (otp ^ ichunk) & mask;
- *(RC4_CHUNK *)out = ochunk;
- }
- key->x = x;
- key->y = y;
- return;
}
}
#define LOOP(in, out) \
