diff options
| author | Luigi Rizzo <lrizzo@google.com> | 2021-09-02 14:56:46 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-09-03 09:58:13 -0700 |
| commit | 5b78ed24e8ec48602c1d6f5a188e58d000c81e2b (patch) | |
| tree | fb2e4dea2199850c8ab0ca7492acab96a06a15a0 | |
| parent | e15710bf04063766f428048f4dad7b73b646203f (diff) | |
mm/pagemap: add mmap_assert_locked() annotations to find_vma*()
find_vma() and variants need protection when used. This patch adds
mmap_assert_lock() calls in the functions.
To make sure the invariant is satisfied, we also need to add a
mmap_read_lock() around the get_user_pages_remote() call in
get_arg_page(). The lock is not strictly necessary because the mm has
been newly created, but the extra cost is limited because the same mutex
was also acquired shortly before in __bprm_mm_init(), so it is hot and
uncontended.
[penguin-kernel@i-love.sakura.ne.jp: TOMOYO needs the same protection which get_arg_page() needs]
Link: https://lkml.kernel.org/r/58bb6bf7-a57e-8a40-e74b-39584b415152@i-love.sakura.ne.jp
Link: https://lkml.kernel.org/r/20210731175341.3458608-1-lrizzo@google.com
Signed-off-by: Luigi Rizzo <lrizzo@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/exec.c | 2 | ||||
| -rw-r--r-- | mm/mmap.c | 2 | ||||
| -rw-r--r-- | security/tomoyo/domain.c | 13 |
3 files changed, 13 insertions, 4 deletions
diff --git a/fs/exec.c b/fs/exec.c index 41a888d4edde..fd292e9da4f9 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -217,8 +217,10 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, * We are doing an exec(). 'current' is the process * doing the exec and bprm->mm is the new process's mm. */ + mmap_read_lock(bprm->mm); ret = get_user_pages_remote(bprm->mm, pos, 1, gup_flags, &page, NULL, NULL); + mmap_read_unlock(bprm->mm); if (ret <= 0) return NULL; diff --git a/mm/mmap.c b/mm/mmap.c index ca54d36d203a..79f4f8ae43ec 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -534,6 +534,7 @@ static int find_vma_links(struct mm_struct *mm, unsigned long addr, { struct rb_node **__rb_link, *__rb_parent, *rb_prev; + mmap_assert_locked(mm); __rb_link = &mm->mm_rb.rb_node; rb_prev = __rb_parent = NULL; @@ -2303,6 +2304,7 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) struct rb_node *rb_node; struct vm_area_struct *vma; + mmap_assert_locked(mm); /* Check the cache first. */ vma = vmacache_find(mm, addr); if (likely(vma)) diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c index 98d985895ec8..31af29f669d2 100644 --- a/security/tomoyo/domain.c +++ b/security/tomoyo/domain.c @@ -897,6 +897,9 @@ bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos, struct tomoyo_page_dump *dump) { struct page *page; +#ifdef CONFIG_MMU + int ret; +#endif /* dump->data is released by tomoyo_find_next_domain(). */ if (!dump->data) { @@ -909,11 +912,13 @@ bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos, /* * This is called at execve() time in order to dig around * in the argv/environment of the new proceess - * (represented by bprm). 'current' is the process doing - * the execve(). + * (represented by bprm). */ - if (get_user_pages_remote(bprm->mm, pos, 1, - FOLL_FORCE, &page, NULL, NULL) <= 0) + mmap_read_lock(bprm->mm); + ret = get_user_pages_remote(bprm->mm, pos, 1, + FOLL_FORCE, &page, NULL, NULL); + mmap_read_unlock(bprm->mm); + if (ret <= 0) return false; #else page = bprm->page[pos / PAGE_SIZE]; |