diff --git a/kernel-src/arch/x86-64/syscall.asm b/kernel-src/arch/x86-64/syscall.asm
index f62735ad..a4218695 100644
--- a/kernel-src/arch/x86-64/syscall.asm
+++ b/kernel-src/arch/x86-64/syscall.asm
@@ -32,6 +32,7 @@ extern syscall_linkat
 extern syscall_readlinkat
 extern syscall_fchmod
 extern syscall_fchmodat
+extern syscall_umask
 syscalltab:
 dq syscall_print
 dq syscall_mmap
@@ -66,7 +67,8 @@ dq syscall_linkat
 dq syscall_readlinkat
 dq syscall_fchmod
 dq syscall_fchmodat
-syscallcount equ 33
+dq syscall_umask
+syscallcount equ 34
 section .text
 global arch_syscall_entry
 ; on entry:
diff --git a/kernel-src/arch/x86-64/syscalllog.c b/kernel-src/arch/x86-64/syscalllog.c
index c5095163..040699ad 100644
--- a/kernel-src/arch/x86-64/syscalllog.c
+++ b/kernel-src/arch/x86-64/syscalllog.c
@@ -4,7 +4,7 @@
 
 #ifdef SYSCALL_LOGGING
 
-#define SYSCALL_COUNT 33
+#define SYSCALL_COUNT 34
 #define LOGSTR(x) arch_e9_puts(x)
 
 static char *name[] = {
@@ -40,7 +40,8 @@ static char *name[] = {
 	"linkat",
 	"readlinkat",
 	"fchmod",
-	"fchmodat"
+	"fchmodat",
+	"umask"
 };
 
 static char *args[] = {
@@ -76,7 +77,8 @@ static char *args[] = {
 	"olddirfd %d oldpath %s newdirfd %d oldpath %s flags %d type %d", // linkat
 	"dirfd %d path %s buffer %p buffer length %lu", // readlinkat
 	"fd %d mode %o", // fchmod
-	"dirfd %d path %s mode %o flags %d" // fchmodat
+	"dirfd %d path %s mode %o flags %d", // fchmodat
+	"mode %o" // umask
 };
 
 #endif
diff --git a/kernel-src/include/kernel/scheduler.h b/kernel-src/include/kernel/scheduler.h
index 28607eac..0a0bbb25 100644
--- a/kernel-src/include/kernel/scheduler.h
+++ b/kernel-src/include/kernel/scheduler.h
@@ -67,6 +67,8 @@ typedef struct proc_t {
 
 #include <arch/cpu.h>
 
+#define UMASK(mode) ((mode) & ~_cpu()->thread->proc->umask)
+
 extern proc_t *sched_initproc;
 
 void sched_init();
diff --git a/kernel-src/sys/syscalls/chmod.c b/kernel-src/sys/syscalls/chmod.c
index 446e92dc..125130af 100644
--- a/kernel-src/sys/syscalls/chmod.c
+++ b/kernel-src/sys/syscalls/chmod.c
@@ -11,7 +11,7 @@ static int dochmod(vnode_t *node, mode_t mode) {
 	if (e)
 		return e;
 
-	attr.mode = mode;
+	attr.mode = UMASK(mode);
 
 	return VOP_SETATTR(node, &attr, cred);
 }
diff --git a/kernel-src/sys/syscalls/linkat.c b/kernel-src/sys/syscalls/linkat.c
index a117cea1..e6fb67b8 100644
--- a/kernel-src/sys/syscalls/linkat.c
+++ b/kernel-src/sys/syscalls/linkat.c
@@ -40,7 +40,8 @@ syscallret_t syscall_linkat(context_t *, int olddirfd, const char *uoldpath, int
 
 	vattr_t attr = {
 		.gid = _cpu()->thread->proc->cred.gid,
-		.uid = _cpu()->thread->proc->cred.uid
+		.uid = _cpu()->thread->proc->cred.uid,
+		.mode = UMASK(0777)
 	};
 
 	ret.errno = vfs_link(olddirnode, oldpath, newdirnode, newpath, type == 0 ? V_TYPE_REGULAR : V_TYPE_LINK, &attr);
diff --git a/kernel-src/sys/syscalls/mkdirat.c b/kernel-src/sys/syscalls/mkdirat.c
index 04c17de1..797996dc 100644
--- a/kernel-src/sys/syscalls/mkdirat.c
+++ b/kernel-src/sys/syscalls/mkdirat.c
@@ -26,7 +26,7 @@ syscallret_t syscall_mkdirat(context_t *, int dirfd, const char *upath, mode_t m
 		goto cleanup;
 
 	vattr_t attr = {
-		.mode = mode,
+		.mode = UMASK(mode),
 		.gid = _cpu()->thread->proc->cred.gid,
 		.uid = _cpu()->thread->proc->cred.uid
 	};
diff --git a/kernel-src/sys/syscalls/open.c b/kernel-src/sys/syscalls/open.c
index 78d81955..07f99c7d 100644
--- a/kernel-src/sys/syscalls/open.c
+++ b/kernel-src/sys/syscalls/open.c
@@ -35,7 +35,7 @@ syscallret_t syscall_openat(context_t *context, int dirfd, const char *path, int
 
 	if (ret.errno == ENOENT && (flags & O_CREAT)) {
 		vattr_t attr = {
-			.mode = mode,
+			.mode = UMASK(mode),
 			.gid = _cpu()->thread->proc->cred.gid,
 			.uid = _cpu()->thread->proc->cred.uid
 		};
diff --git a/kernel-src/sys/syscalls/umask.c b/kernel-src/sys/syscalls/umask.c
new file mode 100644
index 00000000..09304644
--- /dev/null
+++ b/kernel-src/sys/syscalls/umask.c
@@ -0,0 +1,14 @@
+#include <kernel/syscalls.h>
+#include <arch/cpu.h>
+
+syscallret_t syscall_umask(context_t *, mode_t mode) {
+	syscallret_t ret = {
+		.errno = 0
+	};
+
+	mode &= 0777;
+
+	ret.ret = __atomic_exchange_n(&_cpu()->thread->proc->umask, mode, __ATOMIC_SEQ_CST);
+
+	return ret;
+}
diff --git a/patches/mlibc/jinx-working-patch.patch b/patches/mlibc/jinx-working-patch.patch
index de4879e5..2a93c090 100644
--- a/patches/mlibc/jinx-working-patch.patch
+++ b/patches/mlibc/jinx-working-patch.patch
@@ -133,10 +133,10 @@ index 0000000..e5b087a
 +
 diff --git mlibc-workdir/sysdeps/astral/generic/generic.cpp mlibc-workdir/sysdeps/astral/generic/generic.cpp
 new file mode 100644
-index 0000000..569f811
+index 0000000..74cb539
 --- /dev/null
 +++ mlibc-workdir/sysdeps/astral/generic/generic.cpp
-@@ -0,0 +1,343 @@
+@@ -0,0 +1,350 @@
 +#include <bits/ensure.h>
 +#include <mlibc/debug.hpp>
 +#include <mlibc/all-sysdeps.hpp>
@@ -211,6 +211,13 @@ index 0000000..569f811
 +		return 0;
 +	}
 +
++	int sys_umask(mode_t mode, mode_t *old) {
++		long ret;
++		long error = syscall(SYSCALL_UMASK, &ret, mode);
++		*old = ret;
++		return error;
++	}
++
 +	int sys_fchmod(int fd, mode_t mode) {
 +		long ret;
 +		return syscall(SYSCALL_FCHMOD, &ret, fd, mode);
@@ -499,10 +506,10 @@ index 0000000..990eca0
 +#endif
 diff --git mlibc-workdir/sysdeps/astral/include/astral/syscall.h mlibc-workdir/sysdeps/astral/include/astral/syscall.h
 new file mode 100644
-index 0000000..d058baa
+index 0000000..7f39915
 --- /dev/null
 +++ mlibc-workdir/sysdeps/astral/include/astral/syscall.h
-@@ -0,0 +1,56 @@
+@@ -0,0 +1,57 @@
 +#ifndef _SYSCALL_H_INCLUDE
 +#define _SYSCALL_H_INCLUDE
 +
@@ -539,6 +546,7 @@ index 0000000..d058baa
 +#define SYSCALL_READLINKAT 30
 +#define SYSCALL_FCHMOD 31
 +#define SYSCALL_FCHMODAT 32
++#define SYSCALL_UMASK 33
 +
 +#include <stddef.h>
 +#include <stdint.h>