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Refactor disable_execute() and my_execve() into exec_common.c for

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use by sesh.c.  This fixes NOEXEC when SELinux is used.  Instead
of disabling exec in exec_setup(), disable it immediately before
executing the command.  Adapted from a diff by Arno Schuring.
This commit is contained in:
Todd C. Miller
2012-01-25 14:58:02 -05:00
parent e852bf4374
commit d11e7febbc
10 changed files with 240 additions and 140 deletions
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83
src/sudo.c
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@@ -83,9 +83,6 @@
# endif /* __hpux */
# include <prot.h>
#endif /* HAVE_GETPRPWNAM && HAVE_SET_AUTH_PARAMETERS */
#ifdef HAVE_PRIV_SET
# include <priv.h>
#endif
#if defined(HAVE_STRUCT_KINFO_PROC_P_TDEV) || defined (HAVE_STRUCT_KINFO_PROC_KP_EPROC_E_TDEV)
# include <sys/sysctl.h>
#elif defined(HAVE_STRUCT_KINFO_PROC_KI_TDEV)
@@ -829,81 +826,6 @@ set_project(struct passwd *pw)
}
#endif /* HAVE_PROJECT_H */
/*
* Disable execution of child processes in the command we are about
* to run. On systems with privilege sets, we can remove the exec
* privilege. On other systems we use LD_PRELOAD and the like.
*/
static void
disable_execute(struct command_details *details)
{
#ifdef _PATH_SUDO_NOEXEC
char *cp, **ev, **nenvp;
int env_len = 0, env_size = 128;
#endif /* _PATH_SUDO_NOEXEC */
debug_decl(disable_execute, SUDO_DEBUG_UTIL)
#ifdef HAVE_PRIV_SET
/* Solaris privileges, remove PRIV_PROC_EXEC post-execve. */
if (priv_set(PRIV_OFF, PRIV_LIMIT, "PRIV_PROC_EXEC", NULL) == 0)
debug_return;
warning(_("unable to remove PRIV_PROC_EXEC from PRIV_LIMIT"));
#endif /* HAVE_PRIV_SET */
#ifdef _PATH_SUDO_NOEXEC
nenvp = emalloc2(env_size, sizeof(char *));
for (ev = details->envp; *ev != NULL; ev++) {
if (env_len + 2 > env_size) {
env_size += 128;
nenvp = erealloc3(nenvp, env_size, sizeof(char *));
}
/*
* Prune out existing preloaded libraries.
* XXX - should save and append instead of replacing.
*/
# if defined(__darwin__) || defined(__APPLE__)
if (strncmp(*ev, "DYLD_INSERT_LIBRARIES=", sizeof("DYLD_INSERT_LIBRARIES=") - 1) == 0)
continue;
if (strncmp(*ev, "DYLD_FORCE_FLAT_NAMESPACE=", sizeof("DYLD_INSERT_LIBRARIES=") - 1) == 0)
continue;
# elif defined(__osf__) || defined(__sgi)
if (strncmp(*ev, "_RLD_LIST=", sizeof("_RLD_LIST=") - 1) == 0)
continue;
# elif defined(_AIX)
if (strncmp(*ev, "LDR_PRELOAD=", sizeof("LDR_PRELOAD=") - 1) == 0)
continue;
# else
if (strncmp(*ev, "LD_PRELOAD=", sizeof("LD_PRELOAD=") - 1) == 0)
continue;
# endif
nenvp[env_len++] = *ev;
}
/*
* Preload a noexec file? For a list of LD_PRELOAD-alikes, see
* http://www.fortran-2000.com/ArnaudRecipes/sharedlib.html
* XXX - need to support 32-bit and 64-bit variants
*/
# if defined(__darwin__) || defined(__APPLE__)
nenvp[env_len++] = "DYLD_FORCE_FLAT_NAMESPACE=";
cp = fmt_string("DYLD_INSERT_LIBRARIES", sudo_conf_noexec_path());
# elif defined(__osf__) || defined(__sgi)
easprintf(&cp, "_RLD_LIST=%s:DEFAULT", sudo_conf_noexec_path());
# elif defined(_AIX)
cp = fmt_string("LDR_PRELOAD", sudo_conf_noexec_path());
# else
cp = fmt_string("LD_PRELOAD", sudo_conf_noexec_path());
# endif
if (cp == NULL)
errorx(1, _("unable to allocate memory"));
nenvp[env_len++] = cp;
nenvp[env_len] = NULL;
details->envp = nenvp;
#endif /* _PATH_SUDO_NOEXEC */
debug_return;
}
/*
* Setup the execution environment immediately prior to the call to execve()
* Returns true on success and false on failure.
@@ -1024,9 +946,6 @@ exec_setup(struct command_details *details, const char *ptyname, int ptyfd)
}
}
if (ISSET(details->flags, CD_NOEXEC))
disable_execute(details);
#ifdef HAVE_SETRESUID
if (setresuid(details->uid, details->euid, details->euid) != 0) {
warning(_("unable to change to runas uid (%u, %u)"), details->uid,
@@ -1096,7 +1015,7 @@ run_command(struct command_details *details)
cstat.type = CMD_INVALID;
cstat.val = 0;
sudo_execve(details, &cstat);
sudo_execute(details, &cstat);
switch (cstat.type) {
case CMD_ERRNO: