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https://github.com/sheumann/hush.git
synced 2025-01-03 00:31:16 +00:00
libbb: add bb_unsetenv (taken from hush).
udhcpc: stop filtering environment passed to the script. crond: fix uncovered potential bug (failing unsetenv) mdev: fix uncovered potential bug (failing unsetenv) tcp, udpsvd: fix uncovered potential bug (failing unsetenv) function old new delta safe_setenv - 58 +58 bb_unsetenv - 55 +55 builtin_unset 139 138 -1 tcpudpsvd_main 1843 1830 -13 free_strings_and_unsetenv 87 53 -34 udhcp_run_script 1186 1133 -53 safe_setenv4 62 - -62 ------------------------------------------------------------------------------ (add/remove: 2/1 grow/shrink: 0/4 up/down: 113/-163) Total: -50 bytes
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@ -377,6 +377,7 @@ void xsetuid(uid_t uid) FAST_FUNC;
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void xchdir(const char *path) FAST_FUNC;
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void xchroot(const char *path) FAST_FUNC;
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void xsetenv(const char *key, const char *value) FAST_FUNC;
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void bb_unsetenv(const char *key) FAST_FUNC;
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void xunlink(const char *pathname) FAST_FUNC;
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void xstat(const char *pathname, struct stat *buf) FAST_FUNC;
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int xopen(const char *pathname, int flags) FAST_FUNC FAST_FUNC;
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@ -333,6 +333,29 @@ void FAST_FUNC xsetenv(const char *key, const char *value)
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bb_error_msg_and_die(bb_msg_memory_exhausted);
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}
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/* Handles "VAR=VAL" strings, even those which are part of environ
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* _right now_
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*/
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void FAST_FUNC bb_unsetenv(const char *var)
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{
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char *tp = strchr(var, '=');
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if (!tp) {
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unsetenv(var);
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return;
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}
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/* In case var was putenv'ed, we can't replace '='
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* with NUL and unsetenv(var) - it won't work,
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* env is modified by the replacement, unsetenv
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* sees "VAR" instead of "VAR=VAL" and does not remove it!
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* horror :( */
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tp = xstrndup(var, tp - var);
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unsetenv(tp);
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free(tp);
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}
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// Die with an error message if we can't set gid. (Because resource limits may
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// limit this user to a given number of processes, and if that fills up the
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// setgid() will fail and we'll _still_be_root_, which is bad.)
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@ -252,14 +252,12 @@ int crond_main(int argc UNUSED_PARAM, char **argv)
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/* We set environment *before* vfork (because we want to use vfork),
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* so we cannot use setenv() - repeated calls to setenv() may leak memory!
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* Using putenv(), and freeing memory after unsetenv() won't leak */
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static void safe_setenv4(char **pvar_val, const char *var, const char *val /*, int len*/)
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static void safe_setenv(char **pvar_val, const char *var, const char *val)
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{
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const int len = 4; /* both var names are 4 char long */
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char *var_val = *pvar_val;
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if (var_val) {
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var_val[len] = '\0'; /* nuke '=' */
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unsetenv(var_val);
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bb_unsetenv(var_val);
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free(var_val);
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}
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*pvar_val = xasprintf("%s=%s", var, val);
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@ -270,10 +268,10 @@ static void safe_setenv4(char **pvar_val, const char *var, const char *val /*, i
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static void SetEnv(struct passwd *pas)
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{
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#if SETENV_LEAKS
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safe_setenv4(&env_var_user, "USER", pas->pw_name);
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safe_setenv4(&env_var_home, "HOME", pas->pw_dir);
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safe_setenv(&env_var_user, "USER", pas->pw_name);
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safe_setenv(&env_var_home, "HOME", pas->pw_dir);
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/* if we want to set user's shell instead: */
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/*safe_setenv(env_var_user, "SHELL", pas->pw_shell, 5);*/
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/*safe_setenv(env_var_user, "SHELL", pas->pw_shell);*/
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#else
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xsetenv("USER", pas->pw_name);
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xsetenv("HOME", pas->pw_dir);
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@ -85,8 +85,7 @@ static void undo_xsetenv(void)
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char **pp = env_cur = &env_var[0];
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while (*pp) {
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char *var = *pp;
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*strchrnul(var, '=') = '\0';
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unsetenv(var);
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bb_unsetenv(var);
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free(var);
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*pp++ = NULL;
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}
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@ -119,7 +119,8 @@ static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p,
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}
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option += optlen;
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len -= optlen;
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if (len <= 0) break;
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if (len <= 0)
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break;
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dest += sprintf(dest, " ");
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}
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return ret;
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@ -130,9 +131,8 @@ static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p,
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static char **fill_envp(struct dhcpMessage *packet)
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{
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int num_options = 0;
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int i, j;
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char **envp;
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char *var;
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int i;
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char **envp, **curr;
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const char *opt_name;
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uint8_t *temp;
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char over = 0;
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@ -156,21 +156,16 @@ static char **fill_envp(struct dhcpMessage *packet)
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num_options++;
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}
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envp = xzalloc(sizeof(char *) * (num_options + 5));
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j = 0;
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envp[j++] = xasprintf("interface=%s", client_config.interface);
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var = getenv("PATH");
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if (var)
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envp[j++] = xasprintf("PATH=%s", var);
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var = getenv("HOME");
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if (var)
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envp[j++] = xasprintf("HOME=%s", var);
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curr = envp = xzalloc(sizeof(char *) * (num_options + 3));
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*curr = xasprintf("interface=%s", client_config.interface);
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putenv(*curr++);
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if (packet == NULL)
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return envp;
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envp[j] = xmalloc(sizeof("ip=255.255.255.255"));
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sprintip(envp[j++], "ip=", (uint8_t *) &packet->yiaddr);
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*curr = xmalloc(sizeof("ip=255.255.255.255"));
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sprintip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
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putenv(*curr++);
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opt_name = dhcp_option_strings;
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i = 0;
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@ -178,31 +173,36 @@ static char **fill_envp(struct dhcpMessage *packet)
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temp = get_option(packet, dhcp_options[i].code);
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if (!temp)
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goto next;
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envp[j++] = alloc_fill_opts(temp, &dhcp_options[i], opt_name);
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*curr = alloc_fill_opts(temp, &dhcp_options[i], opt_name);
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putenv(*curr++);
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/* Fill in a subnet bits option for things like /24 */
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if (dhcp_options[i].code == DHCP_SUBNET) {
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uint32_t subnet;
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move_from_unaligned32(subnet, temp);
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envp[j++] = xasprintf("mask=%d", mton(subnet));
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*curr = xasprintf("mask=%d", mton(subnet));
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putenv(*curr++);
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}
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next:
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opt_name += strlen(opt_name) + 1;
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i++;
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}
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if (packet->siaddr) {
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envp[j] = xmalloc(sizeof("siaddr=255.255.255.255"));
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sprintip(envp[j++], "siaddr=", (uint8_t *) &packet->siaddr);
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*curr = xmalloc(sizeof("siaddr=255.255.255.255"));
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sprintip(*curr, "siaddr=", (uint8_t *) &packet->siaddr);
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putenv(*curr++);
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}
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if (!(over & FILE_FIELD) && packet->file[0]) {
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/* watch out for invalid packets */
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packet->file[sizeof(packet->file) - 1] = '\0';
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envp[j++] = xasprintf("boot_file=%s", packet->file);
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*curr = xasprintf("boot_file=%s", packet->file);
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putenv(*curr++);
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}
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if (!(over & SNAME_FIELD) && packet->sname[0]) {
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/* watch out for invalid packets */
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packet->sname[sizeof(packet->sname) - 1] = '\0';
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envp[j++] = xasprintf("sname=%s", packet->sname);
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*curr = xasprintf("sname=%s", packet->sname);
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putenv(*curr++);
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}
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return envp;
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}
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@ -211,29 +211,25 @@ static char **fill_envp(struct dhcpMessage *packet)
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/* Call a script with a par file and env vars */
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void FAST_FUNC udhcp_run_script(struct dhcpMessage *packet, const char *name)
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{
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int pid;
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char **envp, **curr;
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char *argv[3];
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if (client_config.script == NULL)
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return;
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DEBUG("vfork'ing and execle'ing %s", client_config.script);
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DEBUG("vfork'ing and exec'ing %s", client_config.script);
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envp = fill_envp(packet);
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/* call script */
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// can we use wait4pid(spawn(...)) here?
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pid = vfork();
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if (pid < 0) return;
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if (pid == 0) {
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/* close fd's? */
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/* exec script */
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execle(client_config.script, client_config.script,
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name, NULL, envp);
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bb_perror_msg_and_die("exec %s", client_config.script);
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}
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safe_waitpid(pid, NULL, 0);
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for (curr = envp; *curr; curr++)
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argv[0] = (char*) client_config.script;
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argv[1] = (char*) name;
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argv[2] = NULL;
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wait4pid(spawn(argv));
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for (curr = envp; *curr; curr++) {
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bb_unsetenv(*curr);
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free(*curr);
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}
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free(envp);
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}
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14
shell/hush.c
14
shell/hush.c
@ -730,16 +730,8 @@ static void free_strings_and_unsetenv(char **strings, int unset)
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v = strings;
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while (*v) {
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if (unset) {
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char *copy;
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/* *strchrnul(*v, '=') = '\0'; -- BAD
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* In case *v was putenv'ed, we can't
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* unsetenv(*v) after taking out '=':
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* it won't work, env is modified by taking out!
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* horror :( */
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copy = xstrndup(*v, strchrnul(*v, '=') - *v);
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debug_printf_env("unsetenv '%s'\n", copy);
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unsetenv(copy);
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free(copy);
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debug_printf_env("unsetenv '%s'\n", *v);
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bb_unsetenv(*v);
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}
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free(*v++);
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}
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@ -2937,7 +2929,7 @@ static void unset_local_var(const char *name)
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* is ro, and we cannot reach this code on the 1st pass */
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prev->next = cur->next;
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debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr);
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unsetenv(cur->varstr);
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bb_unsetenv(cur->varstr);
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if (!cur->max_len)
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free(cur->varstr);
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free(cur);
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@ -276,8 +276,7 @@ static void make_device(char *path, int delete)
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putenv(s);
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if (system(command) == -1)
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bb_perror_msg_and_die("can't run '%s'", command);
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s[4] = '\0';
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unsetenv(s);
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unsetenv("MDEV");
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free(s);
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free(command);
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}
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