diff --git a/src/log.c b/src/log.c
index 847706d2c..8c9180846 100644
--- a/src/log.c
+++ b/src/log.c
@@ -1914,7 +1914,7 @@ char *lf_ip(char *dst, const struct sockaddr *sockaddr, size_t size, const struc
 		default:
 			return NULL;
 		}
-		if (iret < 0 || iret > size)
+		if (iret < 0 || iret >= size)
 			return NULL;
 		ret += iret;
 	} else {
@@ -1938,7 +1938,7 @@ char *lf_port(char *dst, const struct sockaddr *sockaddr, size_t size, const str
 	if (node->options & LOG_OPT_HEXA) {
 		const unsigned char *port = (const unsigned char *)&((struct sockaddr_in *)sockaddr)->sin_port;
 		iret = snprintf(dst, size, "%02X%02X", port[0], port[1]);
-		if (iret < 0 || iret > size)
+		if (iret < 0 || iret >= size)
 			return NULL;
 		ret += iret;
 	} else {
@@ -3206,7 +3206,7 @@ int sess_build_logline(struct session *sess, struct stream *s, char *dst, size_t
 			case LOG_FMT_TS: // %Ts
 				if (tmp->options & LOG_OPT_HEXA) {
 					iret = snprintf(tmplog, dst + maxsize - tmplog, "%04X", (unsigned int)logs->accept_date.tv_sec);
-					if (iret < 0 || iret > dst + maxsize - tmplog)
+					if (iret < 0 || iret >= dst + maxsize - tmplog)
 						goto out;
 					tmplog += iret;
 				} else {
@@ -3220,7 +3220,7 @@ int sess_build_logline(struct session *sess, struct stream *s, char *dst, size_t
 			case LOG_FMT_MS: // %ms
 			if (tmp->options & LOG_OPT_HEXA) {
 					iret = snprintf(tmplog, dst + maxsize - tmplog, "%02X",(unsigned int)logs->accept_date.tv_usec/1000);
-					if (iret < 0 || iret > dst + maxsize - tmplog)
+					if (iret < 0 || iret >= dst + maxsize - tmplog)
 						goto out;
 					tmplog += iret;
 			} else {
@@ -3837,7 +3837,7 @@ int sess_build_logline(struct session *sess, struct stream *s, char *dst, size_t
 			case LOG_FMT_COUNTER: // %rt
 				if (tmp->options & LOG_OPT_HEXA) {
 					iret = snprintf(tmplog, dst + maxsize - tmplog, "%04X", uniq_id);
-					if (iret < 0 || iret > dst + maxsize - tmplog)
+					if (iret < 0 || iret >= dst + maxsize - tmplog)
 						goto out;
 					tmplog += iret;
 				} else {
@@ -3851,7 +3851,7 @@ int sess_build_logline(struct session *sess, struct stream *s, char *dst, size_t
 			case LOG_FMT_LOGCNT: // %lc
 				if (tmp->options & LOG_OPT_HEXA) {
 					iret = snprintf(tmplog, dst + maxsize - tmplog, "%04X", fe->log_count);
-					if (iret < 0 || iret > dst + maxsize - tmplog)
+					if (iret < 0 || iret >= dst + maxsize - tmplog)
 						goto out;
 					tmplog += iret;
 				} else {
@@ -3873,7 +3873,7 @@ int sess_build_logline(struct session *sess, struct stream *s, char *dst, size_t
 			case LOG_FMT_PID: // %pid
 				if (tmp->options & LOG_OPT_HEXA) {
 					iret = snprintf(tmplog, dst + maxsize - tmplog, "%04X", pid);
-					if (iret < 0 || iret > dst + maxsize - tmplog)
+					if (iret < 0 || iret >= dst + maxsize - tmplog)
 						goto out;
 					tmplog += iret;
 				} else {