From aae4d434bb6130bf292e00a405d8fa29b10bf799 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 21 Jul 2011 14:13:42 +0100 Subject: [PATCH] pagemap: close races with suid execve, CVE-2011-1020 just use mm_for_maps() Signed-off-by: Al Viro (cherry picked from commit ca6b0bf0e086513b9ee5efc0aa5770ecb57778af) CVE-2011-1020 BugLink: http://bugs.launchpad.net/bugs/813026 Signed-off-by: Andy Whitcroft Acked-by: Stefan Bader Signed-off-by: Tim Gardner --- fs/proc/base.c | 4 ++-- fs/proc/task_mmu.c | 7 ++----- 2 files changed, 4 insertions(+), 7 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index f1b3b19..a86bfd3 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -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), @@ -3138,7 +3138,7 @@ 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), diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index c4bec29..3fe21d5 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -731,7 +731,8 @@ 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; @@ -744,10 +745,6 @@ 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; -- 1.7.10.4