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authorSimon Rettberg2019-11-26 11:19:03 +0100
committerSimon Rettberg2019-11-26 11:19:03 +0100
commitf664b97beeb660f0eb0f03930a6b01b41ce33283 (patch)
treec3fee483da82137c5ec9f936f22bb3f3dbb855d1
parentAdd remark that UDP needs support by routers (diff)
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Move packet size overflow checking around
-rw-r--r--jawol.c22
1 files changed, 10 insertions, 12 deletions
diff --git a/jawol.c b/jawol.c
index b301153..d604455 100644
--- a/jawol.c
+++ b/jawol.c
@@ -70,6 +70,11 @@ static const char usage_msg[] =
#include <sys/ioctl.h>
#include <getopt.h>
+#define PACKET_SIZE (200)
+#define CHECK_PACKET_SIZE(x) do { \
+ if ( (x) >= PACKET_SIZE ) { fprintf( stderr, "Packet size overflow.\n" ); abort(); } \
+ } while(0)
+
static struct {
const char *ifname;
struct in_addr dest;
@@ -160,7 +165,7 @@ int main(int argc, char **argv)
static int etherwake(int count, char **maclist)
{
- unsigned char outpack[200];
+ unsigned char outpack[PACKET_SIZE];
int s = rawsocket();
if ( s == -1 )
return 2;
@@ -200,6 +205,7 @@ static int etherwake(int count, char **maclist)
memcpy( outpack + packet_size, options.wolpw, options.wolpwlen );
packet_size += options.wolpwlen;
}
+ CHECK_PACKET_SIZE( packet_size );
if ( options.debug ) {
printf( "The final packet for %s is:", maclist[idx] );
for ( int i = 0; i < packet_size; i++ ) printf( " %2.2x", outpack[i] );
@@ -278,7 +284,7 @@ int udpsocket()
static int wakeonlan(int count, char **maclist)
{
struct ether_addr dest_ether;
- unsigned char outpack[200];
+ unsigned char outpack[PACKET_SIZE];
int sock = udpsocket();
if ( sock == -1 )
return 2;
@@ -297,6 +303,7 @@ static int wakeonlan(int count, char **maclist)
memcpy( outpack + packet_size, options.wolpw, options.wolpwlen );
packet_size += options.wolpwlen;
}
+ CHECK_PACKET_SIZE( packet_size );
if ( options.debug ) {
printf( "The final packet for %s is:", maclist[idx] );
for ( int i = 0; i < packet_size; i++ ) printf( " %2.2x", outpack[i] );
@@ -343,16 +350,7 @@ static int get_fill(unsigned char *pkt, const uint8_t *bindestmac, bool with_hea
memcpy(pkt + offset, bindestmac, 6);
offset += 6;
}
- if ( offset > 180 ) {
- fprintf( stderr, "Packet buffer overflow.\n" );
- abort();
- }
- if (options.debug) {
- printf("Packet is ");
- for (i = 0; i < offset; i++)
- printf(" %2.2x", pkt[i]);
- printf(".\n");
- }
+ CHECK_PACKET_SIZE( offset );
return offset;
}