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qrexec: use user shell instead of hardcoded /bin/sh

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Fixes QubesOS/qubes-issues#3139
This commit is contained in:
Marek Marczykowski-Górecki 2017-10-02 04:10:55 +02:00
parent 1497b3b05b
commit 6bf395022a
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GPG Key ID: 063938BA42CFA724
2 changed files with 19 additions and 2 deletions
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14
qrexec/qrexec-agent.c
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@ -144,6 +144,8 @@ void do_exec(const char *cmd)
pid_t child, pid; pid_t child, pid;
char **env; char **env;
char pid_s[32]; char pid_s[32];
char *arg0;
char *shell_basename;
#endif #endif
if (!realcmd) if (!realcmd)
@ -184,6 +186,14 @@ void do_exec(const char *cmd)
pw->pw_shell = strdup(pw->pw_shell); pw->pw_shell = strdup(pw->pw_shell);
endpwent(); endpwent();
shell_basename = basename (pw->pw_shell);
/* this process is going to die shortly, so don't care about freeing */
arg0 = malloc (strlen (shell_basename) + 2);
if (!arg0)
goto error;
arg0[0] = '-';
strcpy (arg0 + 1, shell_basename);
retval = pam_start("qrexec", user, &conv, &pamh); retval = pam_start("qrexec", user, &conv, &pamh);
if (retval != PAM_SUCCESS) if (retval != PAM_SUCCESS)
goto error; goto error;
@ -220,6 +230,7 @@ void do_exec(const char *cmd)
goto error; goto error;
case 0: case 0:
/* child */ /* child */
if (setgid (pw->pw_gid)) if (setgid (pw->pw_gid))
exit(126); exit(126);
if (setuid (pw->pw_uid)) if (setuid (pw->pw_uid))
@ -227,7 +238,8 @@ void do_exec(const char *cmd)
setsid(); setsid();
/* This is a copy but don't care to free as we exec later anyways. */ /* This is a copy but don't care to free as we exec later anyways. */
env = pam_getenvlist (pamh); env = pam_getenvlist (pamh);
execle("/bin/sh", "-sh", "-c", realcmd, (char*)NULL, env);
execle(pw->pw_shell, arg0, "-c", realcmd, (char*)NULL, env);
exit(127); exit(127);
default: default:
/* parent */ /* parent */

7
qrexec/qrexec-fork-server.c
View File

@ -35,6 +35,7 @@
void do_exec(const char *cmd) void do_exec(const char *cmd)
{ {
char *shell;
char buf[strlen(QUBES_RPC_MULTIPLEXER_PATH) + strlen(cmd) - strlen(RPC_REQUEST_COMMAND) + 1]; char buf[strlen(QUBES_RPC_MULTIPLEXER_PATH) + strlen(cmd) - strlen(RPC_REQUEST_COMMAND) + 1];
/* replace magic RPC cmd with RPC multiplexer path */ /* replace magic RPC cmd with RPC multiplexer path */
if (strncmp(cmd, RPC_REQUEST_COMMAND " ", strlen(RPC_REQUEST_COMMAND)+1)==0) { if (strncmp(cmd, RPC_REQUEST_COMMAND " ", strlen(RPC_REQUEST_COMMAND)+1)==0) {
@ -45,7 +46,11 @@ void do_exec(const char *cmd)
signal(SIGCHLD, SIG_DFL); signal(SIGCHLD, SIG_DFL);
signal(SIGPIPE, SIG_DFL); signal(SIGPIPE, SIG_DFL);
execl("/bin/sh", "sh", "-c", cmd, NULL); shell = getenv("SHELL");
if (!shell)
shell = "/bin/sh";
execl(shell, basename(shell), "-c", cmd, NULL);
perror("execl"); perror("execl");
exit(1); exit(1);
} }