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If the tty lives on a devpts filesystem, stash the ctime in the tty

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ticket file, as it is not updated when the tty is written to.
This helps us determine when a tty has been reused without the
user authenticating again with sudo.
This commit is contained in:
Todd C. Miller
2010-05-11 14:25:14 -04:00
parent 8ea8de47fa
commit a331dcb46a
1 changed files with 33 additions and 14 deletions
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47
plugins/sudoers/check.c
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@@ -25,6 +25,9 @@
#include <sys/param.h>
#include <sys/time.h>
#include <sys/stat.h>
#ifdef __linux__
#include <sys/vfs.h>
#endif
#ifndef __TANDEM
# include <sys/file.h>
#endif
@@ -84,6 +87,7 @@ static int timestamp_status(char *, char *, char *, int);
static char *expand_prompt(char *, char *, char *);
static void lecture(int);
static void update_timestamp(char *, char *);
static int tty_is_devpts(const char *);
/*
* This function only returns if the user can successfully
@@ -104,20 +108,8 @@ check_user(int validated, int mode)
tty_info.dev = sb.st_dev;
tty_info.ino = sb.st_ino;
tty_info.rdev = sb.st_rdev;
#ifdef notyet
ctim_get(&sb, &tty_info.ctime);
if (stat("/", &sb) == 0) {
/*
* If tty does not reside on root partition, we assume it lives
* on a devfs without real ctime values (FreeBSD, Mac OS X).
* XXX - would like a smarter way to check this.
*/
if (sb.st_dev != tty_info.dev) {
tty_info.ctime.tv_sec = 0;
tty_info.ctime.tv_usec = 0;
}
}
#endif
if (tty_is_devpts(user_ttypath))
ctim_get(&sb, &tty_info.ctime);
}
/* Always prompt for a password when -k was specified with the command. */
@@ -669,3 +661,30 @@ remove_timestamp(int remove)
efree(timestampdir);
efree(timestampfile);
}
/*
* Returns TRUE if tty lives on a devpts filesystem, else FALSE.
* Unlike most filesystems, the ctime of devpts nodes is not updated when
* the device node is written to, only when the inode's status changes,
* typically via the chmod, chown, link, rename, or utimes system calls.
* Since the ctime is "stable" in this case, we can stash it the tty ticket
* file and use it to determine whether the tty ticket file is stale.
*/
static int
tty_is_devpts(const char *tty)
{
int retval = FALSE;
#ifdef __linux__
struct statfs sfs;
#ifndef DEVPTS_SUPER_MAGIC
# define DEVPTS_SUPER_MAGIC 0x1cd1
#endif
if (statfs(tty, &sfs) == 0) {
if (sfs.f_type == DEVPTS_SUPER_MAGIC)
retval = TRUE;
}
#endif /* __linux__ */
return retval;
}