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Avoid warnings about signedness in comparisons. See 2150

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dmiller
2020-10-15 17:45:48 +00:00
parent f48d12a591
commit 3c5b7107d5
1 changed files with 4 additions and 5 deletions
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9
tcpip.cc
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@@ -1284,7 +1284,7 @@ int readudppacket(const u8 *packet, int readdata) {
The options checked are MSS, WScale, SackOK, Sack, and Timestamp. */ The options checked are MSS, WScale, SackOK, Sack, and Timestamp. */
static bool validateTCPhdr(const u8 *tcpc, unsigned len) { static bool validateTCPhdr(const u8 *tcpc, unsigned len) {
struct tcp_hdr *tcp = (struct tcp_hdr *) tcpc; struct tcp_hdr *tcp = (struct tcp_hdr *) tcpc;
int hdrlen, optlen; unsigned hdrlen, optlen;
hdrlen = tcp->th_off * 4; hdrlen = tcp->th_off * 4;
@@ -1296,6 +1296,7 @@ static bool validateTCPhdr(const u8 *tcpc, unsigned len) {
tcpc += sizeof(struct tcp_hdr); tcpc += sizeof(struct tcp_hdr);
optlen = hdrlen - sizeof(struct tcp_hdr); optlen = hdrlen - sizeof(struct tcp_hdr);
// This macro guarantees optlen does not underflow by returning if optlen < expected
#define OPTLEN_IS(expected) do { \ #define OPTLEN_IS(expected) do { \
if ((expected) == 0 || optlen < (expected) || hdrlen != (expected)) \ if ((expected) == 0 || optlen < (expected) || hdrlen != (expected)) \
return false; \ return false; \
@@ -1347,10 +1348,8 @@ static bool validateTCPhdr(const u8 *tcpc, unsigned len) {
// Only 1 byte left in options, this has to be NOP or EOL // Only 1 byte left in options, this has to be NOP or EOL
return (*tcpc == 0 || *tcpc == 1); return (*tcpc == 0 || *tcpc == 1);
} }
else if (optlen < 0) { // There is no way out of the previous loop that does not satisfy optlen == 0 or optlen == 1
// Last option claimed to be longer than options list assert(optlen == 0);
return false;
}
return true; return true;
} }