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authorLennart Poettering <lennart@poettering.net>2010-04-13 18:50:43 +0200
committerLennart Poettering <lennart@poettering.net>2010-04-13 18:50:43 +0200
commit02a51abad1d6f334599c8d648b18d000b6118eb5 (patch)
tree62bfe37786b30180d73a7426f96dbd3df3664471
parent90a13a44cbae440d973144706aec039c7dab2e38 (diff)
execute: chown() the tty when running owning them
-rw-r--r--execute.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/execute.c b/execute.c
index 5264b5009e..bf9a087c05 100644
--- a/execute.c
+++ b/execute.c
@@ -44,6 +44,9 @@
#include "securebits.h"
#include "cgroup.h"
+/* This assumes there is a 'tty' group */
+#define TTY_MODE 0620
+
static int shift_fds(int fds[], unsigned n_fds) {
int start, restart_from;
@@ -290,6 +293,7 @@ static int setup_output(const ExecContext *context, const char *ident) {
static int setup_error(const ExecContext *context, const char *ident) {
assert(context);
+ assert(ident);
/* This expects the input and output are already set up */
@@ -326,6 +330,26 @@ static int setup_error(const ExecContext *context, const char *ident) {
}
}
+static int chown_terminal(int fd, uid_t uid) {
+ struct stat st;
+
+ assert(fd >= 0);
+ assert(uid >= 0);
+
+ /* This might fail. What matters are the results. */
+ fchown(fd, uid, -1);
+ fchmod(fd, TTY_MODE);
+
+ if (fstat(fd, &st) < 0)
+ return -errno;
+
+ if (st.st_uid != uid ||
+ st.st_mode != TTY_MODE)
+ return -EPERM;
+
+ return 0;
+}
+
static int setup_confirm_stdio(const ExecContext *context,
int *_saved_stdin,
int *_saved_stdout) {
@@ -354,6 +378,11 @@ static int setup_confirm_stdio(const ExecContext *context,
goto fail;
}
+ if (chown_terminal(fd, getuid()) < 0) {
+ r = EXIT_STDIN;
+ goto fail;
+ }
+
if (dup2(fd, STDIN_FILENO) < 0) {
r = EXIT_STDIN;
goto fail;
@@ -814,6 +843,12 @@ int exec_spawn(ExecCommand *command,
goto fail;
}
+ if (is_terminal_input(context->std_input))
+ if (chown_terminal(STDIN_FILENO, uid) < 0) {
+ r = EXIT_STDIN;
+ goto fail;
+ }
+
if (apply_chroot) {
if (context->root_directory)
if (chroot(context->root_directory) < 0) {