From 51e9248e1748fcd3992cf47f6ecf9a3cb776c998 Mon Sep 17 00:00:00 2001 From: Sona Sarmadi Date: Fri, 27 Nov 2015 12:54:04 +0100 Subject: linux-qoriq: mm: CVE-2014-3122 try_to_unmap_cluster() should lock_page() before mlocking Reference http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-3122 Signed-off-by: Sona Sarmadi Signed-off-by: Tudor Florea --- recipes-kernel/linux/files/mm-CVE-2014-3122.patch | 97 +++++++++++++++++++++++ recipes-kernel/linux/linux-qoriq-common.inc | 5 +- 2 files changed, 101 insertions(+), 1 deletion(-) create mode 100644 recipes-kernel/linux/files/mm-CVE-2014-3122.patch diff --git a/recipes-kernel/linux/files/mm-CVE-2014-3122.patch b/recipes-kernel/linux/files/mm-CVE-2014-3122.patch new file mode 100644 index 0000000..609927a --- /dev/null +++ b/recipes-kernel/linux/files/mm-CVE-2014-3122.patch @@ -0,0 +1,97 @@ +commit 400fc13141fe947c38e8485ee9d37066d4533363 +Author: Vlastimil Babka +Date: Mon Apr 7 15:37:50 2014 -0700 + +commit 57e68e9cd65b4b8eb4045a1e0d0746458502554c upstream. + +A BUG_ON(!PageLocked) was triggered in mlock_vma_page() by Sasha Levin +fuzzing with trinity. The call site try_to_unmap_cluster() does not lock +the pages other than its check_page parameter (which is already locked). + +The BUG_ON in mlock_vma_page() is not documented and its purpose is +somewhat unclear, but apparently it serializes against page migration, +which could otherwise fail to transfer the PG_mlocked flag. This would +not be fatal, as the page would be eventually encountered again, but +NR_MLOCK accounting would become distorted nevertheless. This patch adds +a comment to the BUG_ON in mlock_vma_page() and munlock_vma_page() to that +effect. + +The call site try_to_unmap_cluster() is fixed so that for page != +check_page, trylock_page() is attempted (to avoid possible deadlocks as we +already have check_page locked) and mlock_vma_page() is performed only +upon success. If the page lock cannot be obtained, the page is left +without PG_mlocked, which is again not a problem in the whole unevictable +memory design. + +Fixes CVE-2014-3122 +Upstream-Status: Backport + +Signed-off-by: Vlastimil Babka +Signed-off-by: Bob Liu +Reported-by: Sasha Levin +Cc: Wanpeng Li +Cc: Michel Lespinasse +Cc: KOSAKI Motohiro +Acked-by: Rik van Riel +Cc: David Rientjes +Cc: Mel Gorman +Cc: Hugh Dickins +Cc: Joonsoo Kim +Signed-off-by: Andrew Morton +Signed-off-by: Linus Torvalds +Signed-off-by: Jiri Slaby +Signed-off-by: Sona Sarmadi +--- + mm/mlock.c | 2 ++ + mm/rmap.c | 14 ++++++++++++-- + 2 files changed, 14 insertions(+), 2 deletions(-) + +diff --git a/mm/mlock.c b/mm/mlock.c +index 192e6ee..1b12dfa 100644 +--- a/mm/mlock.c ++++ b/mm/mlock.c +@@ -79,6 +79,7 @@ void clear_page_mlock(struct page *page) + */ + void mlock_vma_page(struct page *page) + { ++ /* Serialize with page migration */ + BUG_ON(!PageLocked(page)); + + if (!TestSetPageMlocked(page)) { +@@ -153,6 +154,7 @@ unsigned int munlock_vma_page(struct page *page) + { + unsigned int nr_pages; + ++ /* For try_to_munlock() and to serialize with page migration */ + BUG_ON(!PageLocked(page)); + + if (TestClearPageMlocked(page)) { +diff --git a/mm/rmap.c b/mm/rmap.c +index b9d2222..6e31398 100644 +--- a/mm/rmap.c ++++ b/mm/rmap.c +@@ -1392,9 +1392,19 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount, + BUG_ON(!page || PageAnon(page)); + + if (locked_vma) { +- mlock_vma_page(page); /* no-op if already mlocked */ +- if (page == check_page) ++ if (page == check_page) { ++ /* we know we have check_page locked */ ++ mlock_vma_page(page); + ret = SWAP_MLOCK; ++ } else if (trylock_page(page)) { ++ /* ++ * If we can lock the page, perform mlock. ++ * Otherwise leave the page alone, it will be ++ * eventually encountered again later. ++ */ ++ mlock_vma_page(page); ++ unlock_page(page); ++ } + continue; /* don't unmap */ + } + +-- +1.9.1 + diff --git a/recipes-kernel/linux/linux-qoriq-common.inc b/recipes-kernel/linux/linux-qoriq-common.inc index cbf16e3..d99bdef 100644 --- a/recipes-kernel/linux/linux-qoriq-common.inc +++ b/recipes-kernel/linux/linux-qoriq-common.inc @@ -3,7 +3,10 @@ FILESEXTRAPATHS_prepend := "${THISDIR}/files:" SRC_URI += "file://b4860-hard_irq_disable-bug.patch \ file://0001-sdhci-fix-Timeout-error-messages.patch \ file://powerpc-fsl-booke64-Set-vmemmap_psize-to-4K.patch \ - file://cfg/00013-localversion.cfg \ + file://mm-CVE-2014-3122.patch \ + " + +SRC_URI += "file://cfg/00013-localversion.cfg \ file://cfg/00006-with_modules.cfg \ file://cfg/00001-embedded.cfg \ file://cfg/00012-preempt.cfg \ -- cgit v1.2.3-54-g00ecf