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-rw-r--r--fs/proc/base.c181
1 files changed, 118 insertions, 63 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index daba136..5a670c1 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -191,17 +191,20 @@ static int proc_root_link(struct inode *inode, struct path *path)
return result;
}
-/*
- * Return zero if current may access user memory in @task, -error if not.
- */
-static int check_mem_permission(struct task_struct *task)
+static struct mm_struct *__check_mem_permission(struct task_struct *task)
{
+ struct mm_struct *mm;
+
+ mm = get_task_mm(task);
+ if (!mm)
+ return ERR_PTR(-EINVAL);
+
/*
* A task can always look at itself, in case it chooses
* to use system calls instead of load instructions.
*/
if (task == current)
- return 0;
+ return mm;
/*
* If current is actively ptrace'ing, and would also be
@@ -213,27 +216,53 @@ static int check_mem_permission(struct task_struct *task)
match = (tracehook_tracer_task(task) == current);
rcu_read_unlock();
if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH))
- return 0;
+ return mm;
}
/*
* Noone else is allowed.
*/
- return -EPERM;
+ mmput(mm);
+ return ERR_PTR(-EPERM);
+}
+
+/*
+ * If current may access user memory in @task return a reference to the
+ * corresponding mm, otherwise ERR_PTR.
+ */
+static struct mm_struct *check_mem_permission(struct task_struct *task)
+{
+ struct mm_struct *mm;
+ int err;
+
+ /*
+ * Avoid racing if task exec's as we might get a new mm but validate
+ * against old credentials.
+ */
+ err = mutex_lock_killable(&task->signal->cred_guard_mutex);
+ if (err)
+ return ERR_PTR(err);
+
+ mm = __check_mem_permission(task);
+ mutex_unlock(&task->signal->cred_guard_mutex);
+
+ return mm;
}
struct mm_struct *mm_for_maps(struct task_struct *task)
{
struct mm_struct *mm;
+ int err;
- if (mutex_lock_killable(&task->signal->cred_guard_mutex))
- return NULL;
+ err = mutex_lock_killable(&task->signal->cred_guard_mutex);
+ if (err)
+ return ERR_PTR(err);
mm = get_task_mm(task);
if (mm && mm != current->mm &&
!ptrace_may_access(task, PTRACE_MODE_READ)) {
mmput(mm);
- mm = NULL;
+ mm = ERR_PTR(-EACCES);
}
mutex_unlock(&task->signal->cred_guard_mutex);
@@ -279,9 +308,9 @@ out:
static int proc_pid_auxv(struct task_struct *task, char *buffer)
{
- int res = 0;
- struct mm_struct *mm = get_task_mm(task);
- if (mm) {
+ struct mm_struct *mm = mm_for_maps(task);
+ int res = PTR_ERR(mm);
+ if (mm && !IS_ERR(mm)) {
unsigned int nwords = 0;
do {
nwords += 2;
@@ -318,6 +347,23 @@ static int proc_pid_wchan(struct task_struct *task, char *buffer)
}
#endif /* CONFIG_KALLSYMS */
+static int lock_trace(struct task_struct *task)
+{
+ int err = mutex_lock_killable(&task->signal->cred_guard_mutex);
+ if (err)
+ return err;
+ if (!ptrace_may_access(task, PTRACE_MODE_ATTACH)) {
+ mutex_unlock(&task->signal->cred_guard_mutex);
+ return -EPERM;
+ }
+ return 0;
+}
+
+static void unlock_trace(struct task_struct *task)
+{
+ mutex_unlock(&task->signal->cred_guard_mutex);
+}
+
#ifdef CONFIG_STACKTRACE
#define MAX_STACK_TRACE_DEPTH 64
@@ -327,6 +373,7 @@ static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
{
struct stack_trace trace;
unsigned long *entries;
+ int err;
int i;
entries = kmalloc(MAX_STACK_TRACE_DEPTH * sizeof(*entries), GFP_KERNEL);
@@ -337,15 +384,20 @@ static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
trace.max_entries = MAX_STACK_TRACE_DEPTH;
trace.entries = entries;
trace.skip = 0;
- save_stack_trace_tsk(task, &trace);
- for (i = 0; i < trace.nr_entries; i++) {
- seq_printf(m, "[<%pK>] %pS\n",
- (void *)entries[i], (void *)entries[i]);
+ err = lock_trace(task);
+ if (!err) {
+ save_stack_trace_tsk(task, &trace);
+
+ for (i = 0; i < trace.nr_entries; i++) {
+ seq_printf(m, "[<%pK>] %pS\n",
+ (void *)entries[i], (void *)entries[i]);
+ }
+ unlock_trace(task);
}
kfree(entries);
- return 0;
+ return err;
}
#endif
@@ -508,18 +560,22 @@ static int proc_pid_syscall(struct task_struct *task, char *buffer)
{
long nr;
unsigned long args[6], sp, pc;
+ int res = lock_trace(task);
+ if (res)
+ return res;
if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
- return sprintf(buffer, "running\n");
-
- if (nr < 0)
- return sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
-
- return sprintf(buffer,
+ res = sprintf(buffer, "running\n");
+ else if (nr < 0)
+ res = sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
+ else
+ res = sprintf(buffer,
"%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
nr,
args[0], args[1], args[2], args[3], args[4], args[5],
sp, pc);
+ unlock_trace(task);
+ return res;
}
#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
@@ -775,19 +831,14 @@ static ssize_t mem_read(struct file * file, char __user * buf,
if (!task)
goto out_no_task;
- ret = check_mem_permission(task);
- if (ret)
- goto out;
-
ret = -ENOMEM;
page = (char *)__get_free_page(GFP_TEMPORARY);
if (!page)
goto out;
- ret = 0;
-
- mm = get_task_mm(task);
- if (!mm)
+ mm = check_mem_permission(task);
+ ret = PTR_ERR(mm);
+ if (IS_ERR(mm))
goto out_free;
ret = -EIO;
@@ -801,8 +852,8 @@ static ssize_t mem_read(struct file * file, char __user * buf,
int this_len, retval;
this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
- retval = access_process_vm(task, src, page, this_len, 0);
- if (!retval || check_mem_permission(task)) {
+ retval = access_remote_vm(mm, src, page, this_len, 0);
+ if (!retval) {
if (!ret)
ret = -EIO;
break;
@@ -830,10 +881,6 @@ out_no_task:
return ret;
}
-#define mem_write NULL
-
-#ifndef mem_write
-/* This is a security hazard */
static ssize_t mem_write(struct file * file, const char __user *buf,
size_t count, loff_t *ppos)
{
@@ -841,19 +888,25 @@ static ssize_t mem_write(struct file * file, const char __user *buf,
char *page;
struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
unsigned long dst = *ppos;
+ struct mm_struct *mm;
copied = -ESRCH;
if (!task)
goto out_no_task;
- copied = check_mem_permission(task);
- if (copied)
- goto out;
+ mm = check_mem_permission(task);
+ copied = PTR_ERR(mm);
+ if (IS_ERR(mm))
+ goto out_task;
+
+ copied = -EIO;
+ if (file->private_data != (void *)((long)current->self_exec_id))
+ goto out_mm;
copied = -ENOMEM;
page = (char *)__get_free_page(GFP_TEMPORARY);
if (!page)
- goto out;
+ goto out_mm;
copied = 0;
while (count > 0) {
@@ -864,7 +917,7 @@ static ssize_t mem_write(struct file * file, const char __user *buf,
copied = -EFAULT;
break;
}
- retval = access_process_vm(task, dst, page, this_len, 1);
+ retval = access_remote_vm(mm, dst, page, this_len, 1);
if (!retval) {
if (!copied)
copied = -EIO;
@@ -877,12 +930,13 @@ static ssize_t mem_write(struct file * file, const char __user *buf,
}
*ppos = dst;
free_page((unsigned long) page);
-out:
+out_mm:
+ mmput(mm);
+out_task:
put_task_struct(task);
out_no_task:
return copied;
}
-#endif
loff_t mem_lseek(struct file *file, loff_t offset, int orig)
{
@@ -919,21 +973,18 @@ static ssize_t environ_read(struct file *file, char __user *buf,
if (!task)
goto out_no_task;
- ret = -EPERM;
- if (!ptrace_may_access(task, PTRACE_MODE_READ))
- goto out;
-
ret = -ENOMEM;
page = (char *)__get_free_page(GFP_TEMPORARY);
if (!page)
goto out;
- ret = 0;
- mm = get_task_mm(task);
- if (!mm)
+ mm = mm_for_maps(task);
+ ret = PTR_ERR(mm);
+ if (!mm || IS_ERR(mm))
goto out_free;
+ ret = 0;
while (count > 0) {
int this_len, retval, max_len;
@@ -2751,8 +2802,12 @@ static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
- seq_printf(m, "%08x\n", task->personality);
- return 0;
+ int err = lock_trace(task);
+ if (!err) {
+ seq_printf(m, "%08x\n", task->personality);
+ unlock_trace(task);
+ }
+ return err;
}
/*
@@ -2771,7 +2826,7 @@ static const struct pid_entry tgid_base_stuff[] = {
REG("environ", S_IRUSR, proc_environ_operations),
INF("auxv", S_IRUSR, proc_pid_auxv),
ONE("status", S_IRUGO, proc_pid_status),
- ONE("personality", S_IRUSR, proc_pid_personality),
+ ONE("personality", S_IRUGO, proc_pid_personality),
INF("limits", S_IRUGO, proc_pid_limits),
#ifdef CONFIG_SCHED_DEBUG
REG("sched", S_IRUGO|S_IWUSR, proc_pid_sched_operations),
@@ -2781,7 +2836,7 @@ static const struct pid_entry tgid_base_stuff[] = {
#endif
REG("comm", S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
- INF("syscall", S_IRUSR, proc_pid_syscall),
+ INF("syscall", S_IRUGO, proc_pid_syscall),
#endif
INF("cmdline", S_IRUGO, proc_pid_cmdline),
ONE("stat", S_IRUGO, proc_tgid_stat),
@@ -2800,7 +2855,7 @@ static const struct pid_entry tgid_base_stuff[] = {
#ifdef CONFIG_PROC_PAGE_MONITOR
REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
REG("smaps", S_IRUGO, proc_smaps_operations),
- REG("pagemap", S_IRUSR, proc_pagemap_operations),
+ REG("pagemap", S_IRUGO, proc_pagemap_operations),
#endif
#ifdef CONFIG_SECURITY
DIR("attr", S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
@@ -2809,7 +2864,7 @@ static const struct pid_entry tgid_base_stuff[] = {
INF("wchan", S_IRUGO, proc_pid_wchan),
#endif
#ifdef CONFIG_STACKTRACE
- ONE("stack", S_IRUSR, proc_pid_stack),
+ ONE("stack", S_IRUGO, proc_pid_stack),
#endif
#ifdef CONFIG_SCHEDSTATS
INF("schedstat", S_IRUGO, proc_pid_schedstat),
@@ -3111,14 +3166,14 @@ static const struct pid_entry tid_base_stuff[] = {
REG("environ", S_IRUSR, proc_environ_operations),
INF("auxv", S_IRUSR, proc_pid_auxv),
ONE("status", S_IRUGO, proc_pid_status),
- ONE("personality", S_IRUSR, proc_pid_personality),
+ ONE("personality", S_IRUGO, proc_pid_personality),
INF("limits", S_IRUGO, proc_pid_limits),
#ifdef CONFIG_SCHED_DEBUG
REG("sched", S_IRUGO|S_IWUSR, proc_pid_sched_operations),
#endif
REG("comm", S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
- INF("syscall", S_IRUSR, proc_pid_syscall),
+ INF("syscall", S_IRUGO, proc_pid_syscall),
#endif
INF("cmdline", S_IRUGO, proc_pid_cmdline),
ONE("stat", S_IRUGO, proc_tid_stat),
@@ -3136,7 +3191,7 @@ static const struct pid_entry tid_base_stuff[] = {
#ifdef CONFIG_PROC_PAGE_MONITOR
REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
REG("smaps", S_IRUGO, proc_smaps_operations),
- REG("pagemap", S_IRUSR, proc_pagemap_operations),
+ REG("pagemap", S_IRUGO, proc_pagemap_operations),
#endif
#ifdef CONFIG_SECURITY
DIR("attr", S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
@@ -3145,7 +3200,7 @@ static const struct pid_entry tid_base_stuff[] = {
INF("wchan", S_IRUGO, proc_pid_wchan),
#endif
#ifdef CONFIG_STACKTRACE
- ONE("stack", S_IRUSR, proc_pid_stack),
+ ONE("stack", S_IRUGO, proc_pid_stack),
#endif
#ifdef CONFIG_SCHEDSTATS
INF("schedstat", S_IRUGO, proc_pid_schedstat),
@@ -3164,7 +3219,7 @@ static const struct pid_entry tid_base_stuff[] = {
REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
#ifdef CONFIG_AUDITSYSCALL
REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations),
- REG("sessionid", S_IRUSR, proc_sessionid_operations),
+ REG("sessionid", S_IRUGO, proc_sessionid_operations),
#endif
#ifdef CONFIG_FAULT_INJECTION
REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
generated by cgit v1.1 at 2024-12-23 23:11:39 +0000