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After opening a tty device, fstat() and error out if it is not

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a character device.
This commit is contained in:
Todd C. Miller
2017-05-30 10:44:11 -06:00
parent 71e496a901
commit 777abca382
1 changed files with 20 additions and 3 deletions
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23
src/selinux.c
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@@ -29,6 +29,7 @@
#ifdef HAVE_SELINUX #ifdef HAVE_SELINUX
#include <sys/types.h> #include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h> #include <sys/wait.h>
#include <stdio.h> #include <stdio.h>
#include <stdlib.h> #include <stdlib.h>
@@ -149,6 +150,7 @@ relabel_tty(const char *ttyn, int ptyfd)
{ {
security_context_t tty_con = NULL; security_context_t tty_con = NULL;
security_context_t new_tty_con = NULL; security_context_t new_tty_con = NULL;
struct stat sb;
int fd; int fd;
debug_decl(relabel_tty, SUDO_DEBUG_SELINUX) debug_decl(relabel_tty, SUDO_DEBUG_SELINUX)
@@ -161,10 +163,15 @@ relabel_tty(const char *ttyn, int ptyfd)
/* If sudo is not allocating a pty for the command, open current tty. */ /* If sudo is not allocating a pty for the command, open current tty. */
if (ptyfd == -1) { if (ptyfd == -1) {
se_state.ttyfd = open(ttyn, O_RDWR|O_NOCTTY|O_NONBLOCK); se_state.ttyfd = open(ttyn, O_RDWR|O_NOCTTY|O_NONBLOCK);
if (se_state.ttyfd == -1) { if (se_state.ttyfd == -1 || fstat(se_state.ttyfd, &sb) == -1) {
sudo_warn(U_("unable to open %s, not relabeling tty"), ttyn); sudo_warn(U_("unable to open %s, not relabeling tty"), ttyn);
goto bad; goto bad;
} }
if (!S_ISCHR(sb.st_mode)) {
sudo_warn(U_("%s is not a character device, not relabeling tty"),
ttyn);
goto bad;
}
(void)fcntl(se_state.ttyfd, F_SETFL, (void)fcntl(se_state.ttyfd, F_SETFL,
fcntl(se_state.ttyfd, F_GETFL, 0) & ~O_NONBLOCK); fcntl(se_state.ttyfd, F_GETFL, 0) & ~O_NONBLOCK);
} }
@@ -197,10 +204,15 @@ relabel_tty(const char *ttyn, int ptyfd)
if (ptyfd != -1) { if (ptyfd != -1) {
/* Reopen pty that was relabeled, std{in,out,err} are reset later. */ /* Reopen pty that was relabeled, std{in,out,err} are reset later. */
se_state.ttyfd = open(ttyn, O_RDWR|O_NOCTTY, 0); se_state.ttyfd = open(ttyn, O_RDWR|O_NOCTTY, 0);
if (se_state.ttyfd == -1) { if (se_state.ttyfd == -1 || fstat(se_state.ttyfd, &sb) == -1) {
sudo_warn(U_("unable to open %s"), ttyn); sudo_warn(U_("unable to open %s"), ttyn);
goto bad; goto bad;
} }
if (!S_ISCHR(sb.st_mode)) {
sudo_warn(U_("%s is not a character device, not relabeling tty"),
ttyn);
goto bad;
}
if (dup2(se_state.ttyfd, ptyfd) == -1) { if (dup2(se_state.ttyfd, ptyfd) == -1) {
sudo_warn("dup2"); sudo_warn("dup2");
goto bad; goto bad;
@@ -209,10 +221,15 @@ relabel_tty(const char *ttyn, int ptyfd)
/* Re-open tty to get new label and reset std{in,out,err} */ /* Re-open tty to get new label and reset std{in,out,err} */
close(se_state.ttyfd); close(se_state.ttyfd);
se_state.ttyfd = open(ttyn, O_RDWR|O_NOCTTY|O_NONBLOCK); se_state.ttyfd = open(ttyn, O_RDWR|O_NOCTTY|O_NONBLOCK);
if (se_state.ttyfd == -1) { if (se_state.ttyfd == -1 || fstat(se_state.ttyfd, &sb) == -1) {
sudo_warn(U_("unable to open %s"), ttyn); sudo_warn(U_("unable to open %s"), ttyn);
goto bad; goto bad;
} }
if (!S_ISCHR(sb.st_mode)) {
sudo_warn(U_("%s is not a character device, not relabeling tty"),
ttyn);
goto bad;
}
(void)fcntl(se_state.ttyfd, F_SETFL, (void)fcntl(se_state.ttyfd, F_SETFL,
fcntl(se_state.ttyfd, F_GETFL, 0) & ~O_NONBLOCK); fcntl(se_state.ttyfd, F_GETFL, 0) & ~O_NONBLOCK);
for (fd = STDIN_FILENO; fd <= STDERR_FILENO; fd++) { for (fd = STDIN_FILENO; fd <= STDERR_FILENO; fd++) {