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Move noexec handling to sudo front-end where it is documented as being.

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This commit is contained in:
Todd C. Miller
2011-03-10 15:11:49 -05:00
parent c7a7d31905
commit a092d2fdcf
5 changed files with 83 additions and 39 deletions
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80
src/sudo.c
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@@ -450,6 +450,7 @@ command_info_to_details(char * const info[], struct command_details *details)
memset(details, 0, sizeof(*details));
details->closefrom = -1;
details->noexec_file = _PATH_SUDO_NOEXEC;
#define SET_STRING(s, n) \
if (strncmp(s, info[i], sizeof(s) - 1) == 0 && info[i][sizeof(s) - 1]) { \
@@ -504,6 +505,7 @@ command_info_to_details(char * const info[], struct command_details *details)
SET(details->flags, CD_NOEXEC);
break;
}
SET_STRING("noexec_file=", noexec_file)
break;
case 'p':
if (strncmp("preserve_groups=", info[i], sizeof("preserve_groups=") - 1) == 0) {
@@ -754,6 +756,75 @@ 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)
{
char *cp, **ev, **nenvp;
int env_len = 0, env_size = 128;
#ifdef HAVE_PRIV_SET
/* Solaris privileges, remove PRIV_PROC_EXEC post-execve. */
if (priv_set(PRIV_OFF, PRIV_LIMIT, "PRIV_PROC_EXEC", NULL) == 0)
return;
warning("unable to remove PRIV_PROC_EXEC from PRIV_LIMIT");
#endif /* HAVE_PRIV_SET */
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", details->noexec_file);
#elif defined(__osf__) || defined(__sgi)
easprintf(&cp, "_RLD_LIST=%s:DEFAULT", details->noexec_file);
#elif defined(_AIX)
cp = fmt_string("LDR_PRELOAD", details->noexec_file);
#else
cp = fmt_string("LD_PRELOAD", details->noexec_file);
#endif
if (cp == NULL)
error(1, NULL);
nenvp[env_len++] = cp;
nenvp[env_len] = NULL;
details->envp = nenvp;
}
/*
* Setup the execution environment immediately prior to the call to execve()
* Returns TRUE on success and FALSE on failure.
@@ -865,13 +936,8 @@ exec_setup(struct command_details *details, const char *ptyname, int ptyfd)
}
}
/* XXX - should do env-based noexec here too */
#ifdef HAVE_PRIV_SET
if (ISSET(details->flags, CD_NOEXEC)) {
if (priv_set(PRIV_OFF, PRIV_LIMIT, "PRIV_PROC_EXEC", NULL) == -1)
warning("unable to remove PRIV_PROC_EXEC from PRIV_LIMIT");
}
#endif /* HAVE_PRIV_SET */
if (ISSET(details->flags, CD_NOEXEC))
disable_execute(details);
#ifdef HAVE_SETRESUID
if (setresuid(details->uid, details->euid, details->euid) != 0) {