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authorPrasad J Pandit <pjp@fedoraproject.org>2019-07-23 16:17:54 +0530
committerJason Wang <jasowang@redhat.com>2019-07-29 16:29:30 +0800
commit389abe1dd1790c0de7a2f1f422dcdf778b509a16 (patch)
tree13209bb67ac19a10c74c3cf510704c9ab460740c /net/tap.c
parent3283dde4b5b5cce0f96f48d536bebff66d97ce0b (diff)
net: tap: replace snprintf with g_strdup_printf calls
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 <pjp@fedoraproject.org> Reviewed-by: Li Qiang <liq3ea@gmail.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
Diffstat (limited to 'net/tap.c')
-rw-r--r--net/tap.c19
1 files 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 {