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sched/coredump: introduce enum task_dumpable

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Replace the SUID_DUMP_DISABLE/USER/ROOT preprocessor constants with
enum task_dumpable.  Numeric values are preserved (kernel.suid_dumpable
sysctl and prctl(PR_SET_DUMPABLE) ABI), so this is a pure rename with
no behavioral change.

Subsequent commits relocate dumpability onto a per-task structure
where the enum type will allow stronger type-checking on the new API.

Reviewed-by: Jann Horn <jannh@google.com>
Reviewed-by: David Hildenbrand (arm) <david@kernel.org>
Link: https://patch.msgid.link/20260520-work-task_exec_state-v3-1-69f895bc1385@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
This commit is contained in:
Christian Brauner (Amutable)
2026-05-20 23:48:52 +02:00
committed by Christian Brauner
parent 5200f5f493
commit 4f365e7a5d
10 changed files with 27 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/kernel/mte.c
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@@ -538,7 +538,7 @@ static int access_remote_tags(struct task_struct *tsk, unsigned long addr,
return -EPERM;
if (!tsk->ptrace || (current != tsk->parent) ||
((get_dumpable(mm) != SUID_DUMP_USER) &&
((get_dumpable(mm) != TASK_DUMPABLE_OWNER) &&
!ptracer_capable(tsk, mm->user_ns))) {
mmput(mm);
return -EPERM;

4
fs/coredump.c
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@@ -873,7 +873,7 @@ static inline bool coredump_socket(struct core_name *cn, struct coredump_params
static inline bool coredump_force_suid_safe(const struct coredump_params *cprm)
{
/* Require nonrelative corefile path and be extra careful. */
return __get_dumpable(cprm->mm_flags) == SUID_DUMP_ROOT;
return __get_dumpable(cprm->mm_flags) == TASK_DUMPABLE_ROOT;
}
static bool coredump_file(struct core_name *cn, struct coredump_params *cprm,
@@ -1419,7 +1419,7 @@ EXPORT_SYMBOL(dump_align);
void validate_coredump_safety(void)
{
if (suid_dumpable == SUID_DUMP_ROOT &&
if (suid_dumpable == TASK_DUMPABLE_ROOT &&
core_pattern[0] != '/' && core_pattern[0] != '|' && core_pattern[0] != '@') {
coredump_report_failure("Unsafe core_pattern used with fs.suid_dumpable=2: "

8
fs/exec.c
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@@ -1212,7 +1212,7 @@ int begin_new_exec(struct linux_binprm * bprm)
gid_eq(current_egid(), current_gid())))
set_dumpable(current->mm, suid_dumpable);
else
set_dumpable(current->mm, SUID_DUMP_USER);
set_dumpable(current->mm, TASK_DUMPABLE_OWNER);
perf_event_exec();
@@ -1261,7 +1261,7 @@ int begin_new_exec(struct linux_binprm * bprm)
* wait until new credentials are committed
* by commit_creds() above
*/
if (get_dumpable(me->mm) != SUID_DUMP_USER)
if (get_dumpable(me->mm) != TASK_DUMPABLE_OWNER)
perf_event_exit_task(me);
/*
* cred_guard_mutex must be held at least to this point to prevent
@@ -1906,11 +1906,11 @@ void set_binfmt(struct linux_binfmt *new)
EXPORT_SYMBOL(set_binfmt);
/*
* set_dumpable stores three-value SUID_DUMP_* into mm->flags.
* set_dumpable stores three-value TASK_DUMPABLE_* into mm->flags.
*/
void set_dumpable(struct mm_struct *mm, int value)
{
if (WARN_ON((unsigned)value > SUID_DUMP_ROOT))
if (WARN_ON((unsigned)value > TASK_DUMPABLE_ROOT))
return;
__mm_flags_set_mask_dumpable(mm, value);

6
fs/pidfs.c
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@@ -341,11 +341,11 @@ static inline bool pid_in_current_pidns(const struct pid *pid)
static __u32 pidfs_coredump_mask(unsigned long mm_flags)
{
switch (__get_dumpable(mm_flags)) {
case SUID_DUMP_USER:
case TASK_DUMPABLE_OWNER:
return PIDFD_COREDUMP_USER;
case SUID_DUMP_ROOT:
case TASK_DUMPABLE_ROOT:
return PIDFD_COREDUMP_ROOT;
case SUID_DUMP_DISABLE:
case TASK_DUMPABLE_OFF:
return PIDFD_COREDUMP_SKIP;
default:
WARN_ON_ONCE(true);

2
fs/proc/base.c
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@@ -1909,7 +1909,7 @@ void task_dump_owner(struct task_struct *task, umode_t mode,
mm = task->mm;
/* Make non-dumpable tasks owned by some root */
if (mm) {
if (get_dumpable(mm) != SUID_DUMP_USER) {
if (get_dumpable(mm) != TASK_DUMPABLE_OWNER) {
struct user_namespace *user_ns = mm->user_ns;
uid = make_kuid(user_ns, 0);

2
include/linux/mm_types.h
View File

@@ -1908,7 +1908,7 @@ enum {
/*
* The first two bits represent core dump modes for set-user-ID,
* the modes are SUID_DUMP_* defined in linux/sched/coredump.h
* the modes are TASK_DUMPABLE_* defined in linux/sched/coredump.h
*/
#define MMF_DUMPABLE_BITS 2
#define MMF_DUMPABLE_MASK (BIT(MMF_DUMPABLE_BITS) - 1)

15
include/linux/sched/coredump.h
View File

@@ -4,9 +4,16 @@
#include <linux/mm_types.h>
#define SUID_DUMP_DISABLE 0 /* No setuid dumping */
#define SUID_DUMP_USER 1 /* Dump as user of process */
#define SUID_DUMP_ROOT 2 /* Dump as root */
/*
* Task dumpability mode. Gates core dump production and ptrace_attach()
* authorization. The numeric values are stable ABI (suid_dumpable
* sysctl, prctl(PR_SET_DUMPABLE)); do not renumber.
*/
enum task_dumpable {
TASK_DUMPABLE_OFF = 0, /* no dump; ptrace needs CAP_SYS_PTRACE */
TASK_DUMPABLE_OWNER = 1, /* default; dump and ptrace by uid match */
TASK_DUMPABLE_ROOT = 2, /* dump as root; ptrace needs CAP_SYS_PTRACE */
};
static inline unsigned long __mm_flags_get_dumpable(const struct mm_struct *mm)
{
@@ -26,7 +33,7 @@ extern void set_dumpable(struct mm_struct *mm, int value);
/*
* This returns the actual value of the suid_dumpable flag. For things
* that are using this for checking for privilege transitions, it must
* test against SUID_DUMP_USER rather than treating it as a boolean
* test against TASK_DUMPABLE_OWNER rather than treating it as a boolean
* value.
*/
static inline int __get_dumpable(unsigned long mm_flags)

2
kernel/exit.c
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@@ -571,7 +571,7 @@ static void exit_mm(void)
*/
smp_mb__after_spinlock();
local_irq_disable();
current->user_dumpable = (get_dumpable(mm) == SUID_DUMP_USER);
current->user_dumpable = (get_dumpable(mm) == TASK_DUMPABLE_OWNER);
current->mm = NULL;
membarrier_update_current_mm(NULL);
enter_lazy_tlb(mm, current);

4
kernel/ptrace.c
View File

@@ -53,7 +53,7 @@ int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
if (!tsk->ptrace ||
(current != tsk->parent) ||
((get_dumpable(mm) != SUID_DUMP_USER) &&
((get_dumpable(mm) != TASK_DUMPABLE_OWNER) &&
!ptracer_capable(tsk, mm->user_ns))) {
mmput(mm);
return 0;
@@ -276,7 +276,7 @@ static bool task_still_dumpable(struct task_struct *task, unsigned int mode)
{
struct mm_struct *mm = task->mm;
if (mm) {
if (get_dumpable(mm) == SUID_DUMP_USER)
if (get_dumpable(mm) == TASK_DUMPABLE_OWNER)
return true;
return ptrace_has_cap(mm->user_ns, mode);
}

2
kernel/sys.c
View File

@@ -2568,7 +2568,7 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
error = get_dumpable(me->mm);
break;
case PR_SET_DUMPABLE:
if (arg2 != SUID_DUMP_DISABLE && arg2 != SUID_DUMP_USER) {
if (arg2 != TASK_DUMPABLE_OFF && arg2 != TASK_DUMPABLE_OWNER) {
error = -EINVAL;
break;
}