From 389abe1dd1790c0de7a2f1f422dcdf778b509a16 Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Tue, 23 Jul 2019 16:17:54 +0530 Subject: [PATCH] net: tap: replace snprintf with g_strdup_printf calls MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit When invoking qemu-bridge-helper in 'net_bridge_run_helper', instead of using fixed sized buffers, use dynamically allocated ones initialised and returned by g_strdup_printf(). Signed-off-by: Prasad J Pandit Reviewed-by: Li Qiang Reviewed-by: Daniel P. Berrangé Signed-off-by: Jason Wang --- net/tap.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/net/tap.c b/net/tap.c index e8aadd8d4b..fc38029f41 100644 --- a/net/tap.c +++ b/net/tap.c @@ -498,9 +498,9 @@ static int net_bridge_run_helper(const char *helper, const char *bridge, } if (pid == 0) { int open_max = sysconf(_SC_OPEN_MAX), i; - char fd_buf[6+10]; - char br_buf[6+IFNAMSIZ] = {0}; - char helper_cmd[PATH_MAX + sizeof(fd_buf) + sizeof(br_buf) + 15]; + char *fd_buf = NULL; + char *br_buf = NULL; + char *helper_cmd = NULL; for (i = 3; i < open_max; i++) { if (i != sv[1]) { @@ -508,17 +508,17 @@ static int net_bridge_run_helper(const char *helper, const char *bridge, } } - snprintf(fd_buf, sizeof(fd_buf), "%s%d", "--fd=", sv[1]); + fd_buf = g_strdup_printf("%s%d", "--fd=", sv[1]); if (strrchr(helper, ' ') || strrchr(helper, '\t')) { /* assume helper is a command */ if (strstr(helper, "--br=") == NULL) { - snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge); + br_buf = g_strdup_printf("%s%s", "--br=", bridge); } - snprintf(helper_cmd, sizeof(helper_cmd), "%s %s %s %s", - helper, "--use-vnet", fd_buf, br_buf); + helper_cmd = g_strdup_printf("%s %s %s %s", helper, + "--use-vnet", fd_buf, br_buf ? br_buf : ""); parg = args; *parg++ = (char *)"sh"; @@ -527,10 +527,11 @@ static int net_bridge_run_helper(const char *helper, const char *bridge, *parg++ = NULL; execv("/bin/sh", args); + g_free(helper_cmd); } else { /* assume helper is just the executable path name */ - snprintf(br_buf, sizeof(br_buf), "%s%s", "--br=", bridge); + br_buf = g_strdup_printf("%s%s", "--br=", bridge); parg = args; *parg++ = (char *)helper; @@ -541,6 +542,8 @@ static int net_bridge_run_helper(const char *helper, const char *bridge, execv(helper, args); } + g_free(fd_buf); + g_free(br_buf); _exit(1); } else { -- 2.11.4.GIT