pagemap: close races with suid execve
just use mm_for_maps()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index b77236d..df73573 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2797,7 +2797,7 @@
#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 @@
#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),
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 60b9148..c966413 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -729,7 +729,8 @@
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 @@
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;