[PATCH 1/1] proc: Fix ptrace-based permission checks for accessing task maps
From: Corey Wright <hidden>
Date: 2016-02-28 08:42:41
Subsystem:
filesystems (vfs and infrastructure), memory mapping, proc filesystem, the rest · Maintainers:
Alexander Viro, Christian Brauner, Andrew Morton, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
Modify mm_access() calls in fs/proc/task_mmu.c and fs/proc/task_nommu.c to have the mode include PTRACE_MODE_FSCREDS so accessing /proc/pid/maps and /proc/pid/pagemap is not denied to all users. In backporting upstream commit caaee623 to pre-3.18 kernel versions it was overlooked that mm_access() is used in fs/proc/task_*mmu.c as those calls were removed in 3.18 (by upstream commit 29a40ace) and did not exist at the time of the original commit. Signed-off-by: Corey Wright <redacted> Cc: Jann Horn <redacted> --- fs/proc/task_mmu.c | 4 ++-- fs/proc/task_nommu.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 9f285fb..b86db12 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c@@ -170,7 +170,7 @@ static void *m_start(struct seq_file *m, loff_t *pos) if (!priv->task) return ERR_PTR(-ESRCH); - mm = mm_access(priv->task, PTRACE_MODE_READ); + mm = mm_access(priv->task, PTRACE_MODE_READ_FSCREDS); if (!mm || IS_ERR(mm)) return mm; down_read(&mm->mmap_sem);
@@ -1044,7 +1044,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, if (!pm.buffer) goto out_task; - mm = mm_access(task, PTRACE_MODE_READ); + mm = mm_access(task, PTRACE_MODE_READ_FSCREDS); ret = PTR_ERR(mm); if (!mm || IS_ERR(mm)) goto out_free;
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 56123a6..123c198 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c@@ -223,7 +223,7 @@ static void *m_start(struct seq_file *m, loff_t *pos) if (!priv->task) return ERR_PTR(-ESRCH); - mm = mm_access(priv->task, PTRACE_MODE_READ); + mm = mm_access(priv->task, PTRACE_MODE_READ_FSCREDS); if (!mm || IS_ERR(mm)) { put_task_struct(priv->task); priv->task = NULL;
--
1.7.9.5