Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

sanity-check set-id interpreter script paths #1029

Merged
merged 9 commits into from
Dec 31, 2023
Merged

sanity-check set-id interpreter script paths #1029

Changes from all commits
Commits
Show all changes
9 commits
Select commit Hold shift + click to select a range
ba2b8b8
sanity-check set-id interpreter script paths
mrdomino Dec 18, 2023
a5184ba
Remove constructor, do not verify fd with fcntl
mrdomino Dec 18, 2023
aa0d080
path must have at least one character
mrdomino Dec 18, 2023
a66ccdc
restore relative path comment
mrdomino Dec 18, 2023
45ee600
remove ugly `sizeof(DEV_FD) - 1`
mrdomino Dec 18, 2023
dae0d9e
Support linux /proc/self/fd paths
mrdomino Dec 18, 2023
a2d6ae9
Merge branch 'master' into setugid-check
mrdomino Dec 30, 2023
b70dedc
clang-format -i
mrdomino Dec 30, 2023
e2a7c40
Merge branch 'master' into setugid-check
mrdomino Dec 30, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
50 changes: 41 additions & 9 deletions libc/calls/getprogramexecutablename.greg.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -25,11 +25,11 @@
#include "libc/errno.h"
#include "libc/fmt/libgen.h"
#include "libc/intrin/getenv.internal.h"
#include "libc/serialize.h"
#include "libc/limits.h"
#include "libc/macros.internal.h"
#include "libc/nt/runtime.h"
#include "libc/runtime/runtime.h"
#include "libc/serialize.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/at.h"
#include "libc/sysv/consts/ok.h"
Expand All @@ -39,6 +39,13 @@
#define KERN_PROC_PATHNAME_FREEBSD 12
#define KERN_PROC_PATHNAME_NETBSD 5

#define DevFd() (IsBsd() ? "/dev/fd/" : IsLinux() ? "/proc/self/fd/" : 0)
#define StrlenDevFd() \
((IsBsd() ? sizeof("/dev/fd/") \
: IsLinux() ? sizeof("/proc/self/fd/") \
: 0) - \
1)

static struct {
atomic_uint once;
union {
Expand All @@ -54,11 +61,21 @@ static inline int IsAlpha(int c) {
static inline int AllNumDot(const char *s) {
while (true) {
switch (*s++) {
default: return 0;
case 0: return 1;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9': case '.':
; /* continue */
default:
return 0;
case 0:
return 1;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case '.':; /* continue */
}
}
}
Expand All @@ -68,8 +85,7 @@ static inline int AllNumDot(const char *s) {
static int OldApeLoader(char *s) {
char *b;
return !strcmp(s, "/usr/bin/ape") ||
(!strncmp((b = basename(s)), ".ape-", 5) &&
AllNumDot(b + 5));
(!strncmp((b = basename(s)), ".ape-", 5) && AllNumDot(b + 5));
}

// if q exists then turn it into an absolute path. we also try adding
Expand Down Expand Up @@ -134,11 +150,27 @@ static inline void InitProgramExecutableNameImpl(void) {
return;
}

// loader passed us a path. it may be relative.
// see if the loader passed us a path.
if (__program_executable_name) {
if (issetugid()) {
/* we are running as a set-id interpreter script. this is highly unusual.
it means either someone installed their ape loader set-id, or they are
running a system that supports secure set-id interpreter scripts via a
/dev/fd/ path. check for the latter and allow that. otherwise, use the
empty string to obviate the TOCTOU problem between loader and binary.
*/
if (!(b = DevFd()) ||
0 != strncmp(b, __program_executable_name, StrlenDevFd()) ||
!__program_executable_name[StrlenDevFd()] ||
__program_executable_name[StrlenDevFd()] == '.' ||
strchr(__program_executable_name + StrlenDevFd(), '/')) {
goto UseEmpty;
}
}
if (*__program_executable_name == '/') {
return;
}
// loader passed us a relative path; prepend cwd.
if (TryPath(__program_executable_name, 0)) {
goto UseBuf;
}
Expand Down