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bigsize: insist in minimal representation in bigsize_get().

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Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2019-07-30 14:55:12 +09:30
parent 3fa375881a
commit 8349c1a0c2
1 changed files with 28 additions and 4 deletions
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32
common/bigsize.c
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@@ -1,5 +1,9 @@
#include <common/bigsize.h>
#ifndef SUPERVERBOSE
#define SUPERVERBOSE(...)
#endif
size_t bigsize_len(bigsize_t v)
{
if (v < 0xfd) {
@@ -45,28 +49,48 @@ size_t bigsize_put(u8 buf[BIGSIZE_MAX_LEN], bigsize_t v)
size_t bigsize_get(const u8 *p, size_t max, bigsize_t *val)
{
if (max < 1)
if (max < 1) {
SUPERVERBOSE("EOF");
return 0;
}
switch (*p) {
case 0xfd:
if (max < 3)
if (max < 3) {
SUPERVERBOSE("unexpected EOF");
return 0;
}
*val = ((u64)p[1] << 8) + p[2];
if (*val < 0xfd) {
SUPERVERBOSE("decoded varint is not canonical");
return 0;
}
return 3;
case 0xfe:
if (max < 5)
if (max < 5) {
SUPERVERBOSE("unexpected EOF");
return 0;
}
*val = ((u64)p[1] << 24) + ((u64)p[2] << 16)
+ ((u64)p[3] << 8) + p[4];
if ((*val >> 16) == 0) {
SUPERVERBOSE("decoded varint is not canonical");
return 0;
}
return 5;
case 0xff:
if (max < 9)
if (max < 9) {
SUPERVERBOSE("unexpected EOF");
return 0;
}
*val = ((u64)p[1] << 56) + ((u64)p[2] << 48)
+ ((u64)p[3] << 40) + ((u64)p[4] << 32)
+ ((u64)p[5] << 24) + ((u64)p[6] << 16)
+ ((u64)p[7] << 8) + p[8];
if ((*val >> 32) == 0) {
SUPERVERBOSE("decoded varint is not canonical");
return 0;
}
return 9;
default:
*val = *p;