From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Fri, 16 Feb 2018 21:04:35 +0000 (+0100)
Subject: conf: fix run_script_argv()
X-Git-Tag: lxc-3.0.0.beta1~25^2~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=327cce76ad2f435e84b7d53e64a1e0a5edbd568b;p=thirdparty%2Flxc.git

conf: fix run_script_argv()

Make sure that we allocate the buffer **after** we determined how much space we
need in total.
This fixes a SIGBUS/SIGSEGV Stéphane reported on aarch64 and armf.

Reported-by: Stéphane Graber <stgraber@ubuntu.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index f75d69656..c208d5680 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -376,8 +376,6 @@ int run_script_argv(const char *name, unsigned int hook_version,
 	if (size > INT_MAX)
 		return -EFBIG;
 
-	buffer = alloca(size);
-
 	if (hook_version == 0) {
 		size += strlen(hookname);
 		size++;
@@ -390,19 +388,19 @@ int run_script_argv(const char *name, unsigned int hook_version,
 
 		if (size > INT_MAX)
 			return -EFBIG;
+	}
 
+	buffer = alloca(size);
+	if (hook_version == 0)
 		buf_pos = snprintf(buffer, size, "exec %s %s %s %s", script, name, section, hookname);
-		if (buf_pos < 0 || (size_t)buf_pos >= size) {
-			ERROR("Failed to create command line for script \"%s\"", script);
-			return -1;
-		}
-	} else {
+	else
 		buf_pos = snprintf(buffer, size, "exec %s", script);
-		if (buf_pos < 0 || (size_t)buf_pos >= size) {
-			ERROR("Failed to create command line for script \"%s\"", script);
-			return -1;
-		}
+	if (buf_pos < 0 || (size_t)buf_pos >= size) {
+		ERROR("Failed to create command line for script \"%s\"", script);
+		return -1;
+	}
 
+	if (hook_version == 1) {
 		ret = setenv("LXC_HOOK_TYPE", hookname, 1);
 		if (ret < 0) {
 			SYSERROR("Failed to set environment variable: "