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pagemap: close races with suid execve

just use mm_for_maps()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2011-02-15 22:04:37 -05:00
parent 26ec3c646e
commit ca6b0bf0e0
2 changed files with 4 additions and 7 deletions

View File

@ -2797,7 +2797,7 @@ 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),
@ -3133,7 +3133,7 @@ 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),

View File

@ -729,7 +729,8 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
goto out;
ret = -EACCES;
if (!ptrace_may_access(task, PTRACE_MODE_READ))
mm = mm_for_maps(task);
if (!mm)
goto out_task;
ret = -EINVAL;
@ -742,10 +743,6 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
if (!count)
goto out_task;
mm = get_task_mm(task);
if (!mm)
goto out_task;
pm.len = PM_ENTRY_BYTES * (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
pm.buffer = kmalloc(pm.len, GFP_TEMPORARY);
ret = -ENOMEM;