| From a60633336183a7a32e480faa70cd295f0ab40605 Mon Sep 17 00:00:00 2001 |
| From: Dexuan Cui <decui@microsoft.com> |
| Date: Thu, 18 Oct 2018 05:09:32 +0000 |
| Subject: Tools: hv: kvp: Fix a warning of buffer overflow with gcc 8.0.1 |
| |
| [ Upstream commit 4fcba7802c3e15a6e56e255871d6c72f829b9dd8 ] |
| |
| The patch fixes: |
| |
| hv_kvp_daemon.c: In function 'kvp_set_ip_info': |
| hv_kvp_daemon.c:1305:2: note: 'snprintf' output between 41 and 4136 bytes |
| into a destination of size 4096 |
| |
| The "(unsigned int)str_len" is to avoid: |
| |
| hv_kvp_daemon.c:1309:30: warning: comparison of integer expressions of |
| different signedness: 'int' and 'long unsigned int' [-Wsign-compare] |
| |
| Signed-off-by: Dexuan Cui <decui@microsoft.com> |
| Cc: K. Y. Srinivasan <kys@microsoft.com> |
| Cc: Haiyang Zhang <haiyangz@microsoft.com> |
| Cc: Stephen Hemminger <sthemmin@microsoft.com> |
| Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| tools/hv/hv_kvp_daemon.c | 15 +++++++++++++-- |
| 1 file changed, 13 insertions(+), 2 deletions(-) |
| |
| diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c |
| index 3965186b375a..62c9a503ae05 100644 |
| --- a/tools/hv/hv_kvp_daemon.c |
| +++ b/tools/hv/hv_kvp_daemon.c |
| @@ -1172,6 +1172,7 @@ static int kvp_set_ip_info(char *if_name, struct hv_kvp_ipaddr_value *new_val) |
| FILE *file; |
| char cmd[PATH_MAX]; |
| char *mac_addr; |
| + int str_len; |
| |
| /* |
| * Set the configuration for the specified interface with |
| @@ -1295,8 +1296,18 @@ static int kvp_set_ip_info(char *if_name, struct hv_kvp_ipaddr_value *new_val) |
| * invoke the external script to do its magic. |
| */ |
| |
| - snprintf(cmd, sizeof(cmd), KVP_SCRIPTS_PATH "%s %s", |
| - "hv_set_ifconfig", if_file); |
| + str_len = snprintf(cmd, sizeof(cmd), KVP_SCRIPTS_PATH "%s %s", |
| + "hv_set_ifconfig", if_file); |
| + /* |
| + * This is a little overcautious, but it's necessary to suppress some |
| + * false warnings from gcc 8.0.1. |
| + */ |
| + if (str_len <= 0 || (unsigned int)str_len >= sizeof(cmd)) { |
| + syslog(LOG_ERR, "Cmd '%s' (len=%d) may be too long", |
| + cmd, str_len); |
| + return HV_E_FAIL; |
| + } |
| + |
| if (system(cmd)) { |
| syslog(LOG_ERR, "Failed to execute cmd '%s'; error: %d %s", |
| cmd, errno, strerror(errno)); |
| -- |
| 2.19.1 |
| |