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| author | Dexuan Cui <decui@microsoft.com> | 2018-10-18 05:09:32 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-11-11 12:58:27 -0800 |
| commit | 4fcba7802c3e15a6e56e255871d6c72f829b9dd8 (patch) | |
| tree | d12b055179213bb74dc40efaadc757943141f49b | |
| parent | 16d1342bc41ad417812f8a800a1799b5d1c026dc (diff) | |
| download | lwn-4fcba7802c3e15a6e56e255871d6c72f829b9dd8.tar.gz lwn-4fcba7802c3e15a6e56e255871d6c72f829b9dd8.zip | |
Tools: hv: kvp: Fix a warning of buffer overflow with gcc 8.0.1
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>
| -rw-r--r-- | tools/hv/hv_kvp_daemon.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c index bbb2a8ef367c..d7e06fe0270e 100644 --- a/tools/hv/hv_kvp_daemon.c +++ b/tools/hv/hv_kvp_daemon.c @@ -1178,6 +1178,7 @@ 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 @@ -1301,8 +1302,18 @@ 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)); |