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-rw-r--r--fs/exec.c5
-rw-r--r--fs/namei.c9
-rw-r--r--fs/readdir.c15
-rw-r--r--include/linux/dcache.h6
-rw-r--r--include/linux/fs.h1
-rw-r--r--include/linux/sched.h8
-rw-r--r--include/linux/uidgid.h3
-rw-r--r--kernel/exit.c4
-rw-r--r--kernel/fork.c1
-rw-r--r--kernel/sched/core.c32
10 files changed, 84 insertions, 0 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 341b872d758f..ebf8c18f6d56 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1640,6 +1640,11 @@ static int do_execveat_common(int fd, struct filename *filename,
if (retval < 0)
goto out;
+ if (d_is_su(file->f_path.dentry) && capable(CAP_SYS_ADMIN)) {
+ current->flags |= PF_SU;
+ su_exec();
+ }
+
/* execve succeeded */
current->fs->in_exec = 0;
current->in_execve = 0;
diff --git a/fs/namei.c b/fs/namei.c
index fe1612ac009d..24c8e86449b4 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2290,6 +2290,15 @@ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path
if (!err && nd->flags & LOOKUP_DIRECTORY)
if (!d_can_lookup(nd->path.dentry))
err = -ENOTDIR;
+
+ if (!err) {
+ struct super_block *sb = nd->inode->i_sb;
+ if (sb->s_flags & MS_RDONLY) {
+ if (d_is_su(nd->path.dentry) && !su_visible())
+ err = -ENOENT;
+ }
+ }
+
if (!err) {
*path = nd->path;
nd->path.mnt = NULL;
diff --git a/fs/readdir.c b/fs/readdir.c
index 3494d7a8ff65..27807505fc4a 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -39,6 +39,7 @@ int iterate_dir(struct file *file, struct dir_context *ctx)
res = -ENOENT;
if (!IS_DEADDIR(inode)) {
ctx->pos = file->f_pos;
+ ctx->romnt = (inode->i_sb->s_flags & MS_RDONLY);
res = file->f_op->iterate(file, ctx);
file->f_pos = ctx->pos;
fsnotify_access(file);
@@ -50,6 +51,14 @@ out:
}
EXPORT_SYMBOL(iterate_dir);
+static bool hide_name(const char *name, int namlen)
+{
+ if (namlen == 2 && !memcmp(name, "su", 2))
+ if (!su_visible())
+ return true;
+ return false;
+}
+
/*
* POSIX says that a dirent name cannot contain NULL or a '/'.
*
@@ -123,6 +132,8 @@ static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
buf->result = -EOVERFLOW;
return -EOVERFLOW;
}
+ if (hide_name(name, namlen) && buf->ctx.romnt)
+ return 0;
buf->result++;
dirent = buf->dirent;
if (!access_ok(VERIFY_WRITE, dirent,
@@ -204,6 +215,8 @@ static int filldir(struct dir_context *ctx, const char *name, int namlen,
buf->error = -EOVERFLOW;
return -EOVERFLOW;
}
+ if (hide_name(name, namlen) && buf->ctx.romnt)
+ return 0;
dirent = buf->previous;
if (dirent) {
if (__put_user(offset, &dirent->d_off))
@@ -286,6 +299,8 @@ static int filldir64(struct dir_context *ctx, const char *name, int namlen,
buf->error = -EINVAL; /* only used if we fail.. */
if (reclen > buf->count)
return -EINVAL;
+ if (hide_name(name, namlen) && buf->ctx.romnt)
+ return 0;
dirent = buf->previous;
if (dirent) {
if (__put_user(offset, &dirent->d_off))
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index c066f6b56e58..d57e8a6c2f2c 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -522,6 +522,12 @@ static inline bool d_is_fallthru(const struct dentry *dentry)
return dentry->d_flags & DCACHE_FALLTHRU;
}
+static inline bool d_is_su(const struct dentry *dentry)
+{
+ return dentry &&
+ dentry->d_name.len == 2 &&
+ !memcmp(dentry->d_name.name, "su", 2);
+}
extern int sysctl_vfs_cache_pressure;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 42ac99e898a4..d06b2af25514 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1668,6 +1668,7 @@ typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
struct dir_context {
const filldir_t actor;
loff_t pos;
+ bool romnt;
};
struct block_device_operations;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 70c1f7f9e4fa..c00e7ccd1e89 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -63,6 +63,12 @@ struct sched_param {
#include <asm/processor.h>
+int su_instances(void);
+bool su_running(void);
+bool su_visible(void);
+void su_exec(void);
+void su_exit(void);
+
#define SCHED_ATTR_SIZE_VER0 48 /* sizeof first published struct */
/*
@@ -2407,6 +2413,8 @@ extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut,
#define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */
#define PF_SUSPEND_TASK 0x80000000 /* this thread called freeze_processes and should not be frozen */
+#define PF_SU 0x10000000 /* task is su */
+
/*
* Only the _current_ task can read/write to tsk->flags, but other
* tasks can access tsk->flags in readonly mode for example
diff --git a/include/linux/uidgid.h b/include/linux/uidgid.h
index 03835522dfcb..83504b1be16e 100644
--- a/include/linux/uidgid.h
+++ b/include/linux/uidgid.h
@@ -54,6 +54,9 @@ static inline gid_t __kgid_val(kgid_t gid)
#define GLOBAL_ROOT_UID KUIDT_INIT(0)
#define GLOBAL_ROOT_GID KGIDT_INIT(0)
+#define GLOBAL_SYSTEM_UID KUIDT_INIT(1000)
+#define GLOBAL_SYSTEM_GID KGIDT_INIT(1000)
+
#define INVALID_UID KUIDT_INIT(-1)
#define INVALID_GID KGIDT_INIT(-1)
diff --git a/kernel/exit.c b/kernel/exit.c
index babbc3c0a181..4a8dbc4bf4f6 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -719,6 +719,10 @@ void do_exit(long code)
sched_exit(tsk);
schedtune_exit_task(tsk);
+ if (tsk->flags & PF_SU) {
+ su_exit();
+ }
+
if (unlikely(in_atomic())) {
pr_info("note: %s[%d] exited with preempt_count %d\n",
current->comm, task_pid_nr(current),
diff --git a/kernel/fork.c b/kernel/fork.c
index 92a0df862115..dcdbb9f7216f 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -360,6 +360,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
if (err)
goto free_stack;
+ tsk->flags &= ~PF_SU;
tsk->stack = stack;
err = kaiser_map_thread_stack(tsk->stack);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 6c3f46e759d2..09e1d83a9f09 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -98,6 +98,38 @@
#define CREATE_TRACE_POINTS
#include <trace/events/sched.h>
+static atomic_t __su_instances;
+
+int su_instances(void)
+{
+ return atomic_read(&__su_instances);
+}
+
+bool su_running(void)
+{
+ return su_instances() > 0;
+}
+
+bool su_visible(void)
+{
+ kuid_t uid = current_uid();
+ if (su_running())
+ return true;
+ if (uid_eq(uid, GLOBAL_ROOT_UID) || uid_eq(uid, GLOBAL_SYSTEM_UID))
+ return true;
+ return false;
+}
+
+void su_exec(void)
+{
+ atomic_inc(&__su_instances);
+}
+
+void su_exit(void)
+{
+ atomic_dec(&__su_instances);
+}
+
ATOMIC_NOTIFIER_HEAD(load_alert_notifier_head);
DEFINE_MUTEX(sched_domains_mutex);
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-22 16:58:02 +0000