diff options
-rw-r--r-- | recipes-kernel/linux/linux-ls1/CVE-2016-5195.patch | 100 | ||||
-rw-r--r-- | recipes-kernel/linux/linux-ls1_3.12.bbappend | 1 |
2 files changed, 101 insertions, 0 deletions
diff --git a/recipes-kernel/linux/linux-ls1/CVE-2016-5195.patch b/recipes-kernel/linux/linux-ls1/CVE-2016-5195.patch new file mode 100644 index 0000000..bba2d0e --- /dev/null +++ b/recipes-kernel/linux/linux-ls1/CVE-2016-5195.patch | |||
@@ -0,0 +1,100 @@ | |||
1 | From f949fcd7414197b8e04b07c480d36bc39332ff7b Mon Sep 17 00:00:00 2001 | ||
2 | From: Linus Torvalds <torvalds@linux-foundation.org> | ||
3 | Date: Thu, 13 Oct 2016 13:07:36 -0700 | ||
4 | Subject: mm: remove gup_flags FOLL_WRITE games from __get_user_pages() | ||
5 | |||
6 | commit 19be0eaffa3ac7d8eb6784ad9bdbc7d67ed8e619 upstream. | ||
7 | |||
8 | This is an ancient bug that was actually attempted to be fixed once | ||
9 | (badly) by me eleven years ago in commit 4ceb5db9757a ("Fix | ||
10 | get_user_pages() race for write access") but that was then undone due to | ||
11 | problems on s390 by commit f33ea7f404e5 ("fix get_user_pages bug"). | ||
12 | |||
13 | In the meantime, the s390 situation has long been fixed, and we can now | ||
14 | fix it by checking the pte_dirty() bit properly (and do it better). The | ||
15 | s390 dirty bit was implemented in abf09bed3cce ("s390/mm: implement | ||
16 | software dirty bits") which made it into v3.9. Earlier kernels will | ||
17 | have to look at the page state itself. | ||
18 | |||
19 | Also, the VM has become more scalable, and what used a purely | ||
20 | theoretical race back then has become easier to trigger. | ||
21 | |||
22 | To fix it, we introduce a new internal FOLL_COW flag to mark the "yes, | ||
23 | we already did a COW" rather than play racy games with FOLL_WRITE that | ||
24 | is very fundamental, and then use the pte dirty flag to validate that | ||
25 | the FOLL_COW flag is still valid. | ||
26 | |||
27 | Upstream-Status: Backport | ||
28 | CVE: CVE-2016-5195 | ||
29 | |||
30 | Reported-and-tested-by: Phil "not Paul" Oester <kernel@linuxace.com> | ||
31 | Acked-by: Hugh Dickins <hughd@google.com> | ||
32 | Reviewed-by: Michal Hocko <mhocko@suse.com> | ||
33 | Cc: Andy Lutomirski <luto@kernel.org> | ||
34 | Cc: Kees Cook <keescook@chromium.org> | ||
35 | Cc: Oleg Nesterov <oleg@redhat.com> | ||
36 | Cc: Willy Tarreau <w@1wt.eu> | ||
37 | Cc: Nick Piggin <npiggin@gmail.com> | ||
38 | Cc: Greg Thelen <gthelen@google.com> | ||
39 | Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> | ||
40 | Signed-off-by: Jiri Slaby <jslaby@suse.cz> | ||
41 | Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com> | ||
42 | --- | ||
43 | include/linux/mm.h | 1 + | ||
44 | mm/memory.c | 14 ++++++++++++-- | ||
45 | 2 files changed, 13 insertions(+), 2 deletions(-) | ||
46 | |||
47 | diff --git a/include/linux/mm.h b/include/linux/mm.h | ||
48 | index 79aa518..5676a67 100644 | ||
49 | --- a/include/linux/mm.h | ||
50 | +++ b/include/linux/mm.h | ||
51 | @@ -1749,6 +1749,7 @@ static inline struct page *follow_page(struct vm_area_struct *vma, | ||
52 | #define FOLL_HWPOISON 0x100 /* check page is hwpoisoned */ | ||
53 | #define FOLL_NUMA 0x200 /* force NUMA hinting page fault */ | ||
54 | #define FOLL_MIGRATION 0x400 /* wait for page to replace migration entry */ | ||
55 | +#define FOLL_COW 0x4000 /* internal GUP flag */ | ||
56 | |||
57 | typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr, | ||
58 | void *data); | ||
59 | diff --git a/mm/memory.c b/mm/memory.c | ||
60 | index 6192635..a0c9c6c 100644 | ||
61 | --- a/mm/memory.c | ||
62 | +++ b/mm/memory.c | ||
63 | @@ -1441,6 +1441,16 @@ int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, | ||
64 | } | ||
65 | EXPORT_SYMBOL_GPL(zap_vma_ptes); | ||
66 | |||
67 | +/* | ||
68 | + * FOLL_FORCE can write to even unwritable pte's, but only | ||
69 | + * after we've gone through a COW cycle and they are dirty. | ||
70 | + */ | ||
71 | +static inline bool can_follow_write_pte(pte_t pte, unsigned int flags) | ||
72 | +{ | ||
73 | + return pte_write(pte) || | ||
74 | + ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte)); | ||
75 | +} | ||
76 | + | ||
77 | /** | ||
78 | * follow_page_mask - look up a page descriptor from a user-virtual address | ||
79 | * @vma: vm_area_struct mapping @address | ||
80 | @@ -1550,7 +1560,7 @@ split_fallthrough: | ||
81 | } | ||
82 | if ((flags & FOLL_NUMA) && pte_numa(pte)) | ||
83 | goto no_page; | ||
84 | - if ((flags & FOLL_WRITE) && !pte_write(pte)) | ||
85 | + if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags)) | ||
86 | goto unlock; | ||
87 | |||
88 | page = vm_normal_page(vma, address, pte); | ||
89 | @@ -1858,7 +1868,7 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, | ||
90 | */ | ||
91 | if ((ret & VM_FAULT_WRITE) && | ||
92 | !(vma->vm_flags & VM_WRITE)) | ||
93 | - foll_flags &= ~FOLL_WRITE; | ||
94 | + foll_flags |= FOLL_COW; | ||
95 | |||
96 | cond_resched(); | ||
97 | } | ||
98 | -- | ||
99 | cgit v0.12 | ||
100 | |||
diff --git a/recipes-kernel/linux/linux-ls1_3.12.bbappend b/recipes-kernel/linux/linux-ls1_3.12.bbappend index 8bc21d4..dd43619 100644 --- a/recipes-kernel/linux/linux-ls1_3.12.bbappend +++ b/recipes-kernel/linux/linux-ls1_3.12.bbappend | |||
@@ -8,6 +8,7 @@ SRC_URI += "file://ls1021aiot.dts \ | |||
8 | file://ppp-CVE-2015-8569.patch \ | 8 | file://ppp-CVE-2015-8569.patch \ |
9 | file://net-CVE-2016-5696.patch \ | 9 | file://net-CVE-2016-5696.patch \ |
10 | file://CVE-2016-3136.patch \ | 10 | file://CVE-2016-3136.patch \ |
11 | file://CVE-2016-5195.patch \ | ||
11 | " | 12 | " |
12 | 13 | ||
13 | # fix err: "linux-ls1-3.12-r0 do_deploy: Taskhash mismatch" | 14 | # fix err: "linux-ls1-3.12-r0 do_deploy: Taskhash mismatch" |