From 831830b5a2b5d413407adf380ef62fe17d6fcbf2 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 2 Jan 2008 14:09:57 +0000 Subject: restrict reading from /proc//maps to those who share ->mm or can ptrace pid Contents of /proc/*/maps is sensitive and may become sensitive after open() (e.g. if target originally shares our ->mm and later does exec on suid-root binary). Check at read() (actually, ->start() of iterator) time that mm_struct we'd grabbed and locked is - still the ->mm of target - equal to reader's ->mm or the target is ptracable by reader. Signed-off-by: Al Viro Acked-by: Rik van Riel Signed-off-by: Linus Torvalds --- fs/proc/task_nommu.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'fs/proc/task_nommu.c') diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c index d8b8c7183c24..1932c2ca3457 100644 --- a/fs/proc/task_nommu.c +++ b/fs/proc/task_nommu.c @@ -165,15 +165,13 @@ static void *m_start(struct seq_file *m, loff_t *pos) if (!priv->task) return NULL; - mm = get_task_mm(priv->task); + mm = mm_for_maps(priv->task); if (!mm) { put_task_struct(priv->task); priv->task = NULL; return NULL; } - down_read(&mm->mmap_sem); - /* start from the Nth VMA */ for (vml = mm->context.vmlist; vml; vml = vml->next) if (n-- == 0) -- cgit v1.2.1