c/pve-kernel-qoup
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
dc2b2ba06c
pve-kernel-qoup/CVE-2017-100364-0001-Revert-mm-enlarge-stack-guard-gap.patch
Fabian Grünbichler b4b8080506 replace Stack-Clash fix with upstream version 
sicne the Ubuntu / Suse one seems to have some segfaulting
issues.
2017-06-23 08:57:04 +02:00

462 lines
15 KiB
Diff
Raw Blame History

From 0a0e88a03210365fb82b7ab9cebfccca31aff608 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fabian=20Gr=C3=BCnbichler?= <f.gruenbichler@proxmox.com>
Date: Fri, 23 Jun 2017 08:25:20 +0200
Subject: [PATCH 1/4] Revert "mm: enlarge stack guard gap"
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
This reverts commit fe388e5751e74b3534ee21d01b999795dfc83d39.
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
include/linux/mm.h | 40 +++++++++++---
arch/ia64/mm/fault.c | 2 +-
fs/exec.c | 8 +--
fs/proc/task_mmu.c | 11 ++--
mm/gup.c | 4 +-
mm/memory.c | 35 +++++++++++-
mm/mmap.c | 152 ++++++++++-----------------------------------------
7 files changed, 102 insertions(+), 150 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index fbe65ceafb94..3978a350e9e4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1366,11 +1366,39 @@ int clear_page_dirty_for_io(struct page *page);
int get_cmdline(struct task_struct *task, char *buffer, int buflen);
+/* Is the vma a continuation of the stack vma above it? */
+static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)
+{
+ return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
+}
+
static inline bool vma_is_anonymous(struct vm_area_struct *vma)
{
return !vma->vm_ops;
}
+static inline int stack_guard_page_start(struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ return (vma->vm_flags & VM_GROWSDOWN) &&
+ (vma->vm_start == addr) &&
+ !vma_growsdown(vma->vm_prev, addr);
+}
+
+/* Is the vma a continuation of the stack vma below it? */
+static inline int vma_growsup(struct vm_area_struct *vma, unsigned long addr)
+{
+ return vma && (vma->vm_start == addr) && (vma->vm_flags & VM_GROWSUP);
+}
+
+static inline int stack_guard_page_end(struct vm_area_struct *vma,
+ unsigned long addr)
+{
+ return (vma->vm_flags & VM_GROWSUP) &&
+ (vma->vm_end == addr) &&
+ !vma_growsup(vma->vm_next, addr);
+}
+
int vma_is_stack_for_current(struct vm_area_struct *vma);
extern unsigned long move_page_tables(struct vm_area_struct *vma,
@@ -2111,22 +2139,16 @@ void page_cache_async_readahead(struct address_space *mapping,
pgoff_t offset,
unsigned long size);
-extern unsigned long stack_guard_gap;
/* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
-extern int stack_guard_area(struct vm_area_struct *vma, unsigned long address);
/* CONFIG_STACK_GROWSUP still needs to to grow downwards at some places */
extern int expand_downwards(struct vm_area_struct *vma,
- unsigned long address, unsigned long gap);
-unsigned long expandable_stack_area(struct vm_area_struct *vma,
- unsigned long address, unsigned long *gap);
-
+ unsigned long address);
#if VM_GROWSUP
-extern int expand_upwards(struct vm_area_struct *vma,
- unsigned long address, unsigned long gap);
+extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
#else
- #define expand_upwards(vma, address, gap) (0)
+ #define expand_upwards(vma, address) (0)
#endif
/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index d5caa3cab925..fa6ad95e992e 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -224,7 +224,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
*/
if (address > vma->vm_end + PAGE_SIZE - sizeof(long))
goto bad_area;
- if (expand_upwards(vma, address, 0))
+ if (expand_upwards(vma, address))
goto bad_area;
}
goto good_area;
diff --git a/fs/exec.c b/fs/exec.c
index 5b6383208379..1825e64f8bf3 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -205,7 +205,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
#ifdef CONFIG_STACK_GROWSUP
if (write) {
- ret = expand_downwards(bprm->vma, pos, 0);
+ ret = expand_downwards(bprm->vma, pos);
if (ret < 0)
return NULL;
}
@@ -227,12 +227,6 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
struct rlimit *rlim;
- /*
- * GRWOSUP doesn't really have any gap at this stage because we grow
- * the stack down now. See the expand_downwards above.
- */
- if (!IS_ENABLED(CONFIG_STACK_GROWSUP))
- size -= stack_guard_gap;
acct_arg_size(bprm, size / PAGE_SIZE);
/*
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 75f9099e2ecf..52049b595b0f 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -302,14 +302,11 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
/* We don't show the stack guard page in /proc/maps */
start = vma->vm_start;
+ if (stack_guard_page_start(vma, start))
+ start += PAGE_SIZE;
end = vma->vm_end;
- if (vma->vm_flags & VM_GROWSDOWN) {
- if (stack_guard_area(vma, start))
- start += stack_guard_gap;
- } else if (vma->vm_flags & VM_GROWSUP) {
- if (stack_guard_area(vma, end))
- end -= stack_guard_gap;
- }
+ if (stack_guard_page_end(vma, end))
+ end -= PAGE_SIZE;
seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
diff --git a/mm/gup.c b/mm/gup.c
index 90252d1038b9..bb5f3d69f87e 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -372,7 +372,9 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
if ((*flags & (FOLL_POPULATE | FOLL_MLOCK)) == FOLL_MLOCK)
return -ENOENT;
/* For mm_populate(), just skip the stack guard page. */
- if ((*flags & FOLL_POPULATE) && stack_guard_area(vma, address))
+ if ((*flags & FOLL_POPULATE) &&
+ (stack_guard_page_start(vma, address) ||
+ stack_guard_page_end(vma, address + PAGE_SIZE)))
return -ENOENT;
if (*flags & FOLL_WRITE)
fault_flags |= FAULT_FLAG_WRITE;
diff --git a/mm/memory.c b/mm/memory.c
index fca9dc75a04d..c89214451507 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2714,7 +2714,39 @@ int do_swap_page(struct vm_fault *vmf)
return ret;
}
+/*
+ * This is like a special single-page "expand_{down|up}wards()",
+ * except we must first make sure that 'address{-|+}PAGE_SIZE'
+ * doesn't hit another vma.
+ */
+static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
+{
+ address &= PAGE_MASK;
+ if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
+ struct vm_area_struct *prev = vma->vm_prev;
+
+ /*
+ * Is there a mapping abutting this one below?
+ *
+ * That's only ok if it's the same stack mapping
+ * that has gotten split..
+ */
+ if (prev && prev->vm_end == address)
+ return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
+ return expand_downwards(vma, address - PAGE_SIZE);
+ }
+ if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
+ struct vm_area_struct *next = vma->vm_next;
+
+ /* As VM_GROWSDOWN but s/below/above/ */
+ if (next && next->vm_start == address + PAGE_SIZE)
+ return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
+
+ return expand_upwards(vma, address + PAGE_SIZE);
+ }
+ return 0;
+}
/*
* We enter with non-exclusive mmap_sem (to exclude vma changes,
@@ -2733,8 +2765,7 @@ static int do_anonymous_page(struct vm_fault *vmf)
return VM_FAULT_SIGBUS;
/* Check if we need to add a guard page to the stack */
- if ((vma->vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) &&
- expand_stack(vma, vmf->address) < 0)
+ if (check_stack_guard_page(vma, vmf->address) < 0)
return VM_FAULT_SIGSEGV;
/*
diff --git a/mm/mmap.c b/mm/mmap.c
index 2a3bdf11baf0..4b3a2aaa18e9 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2151,8 +2151,7 @@ find_vma_prev(struct mm_struct *mm, unsigned long addr,
* update accounting. This is shared with both the
* grow-up and grow-down cases.
*/
-static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow,
- unsigned long gap)
+static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
{
struct mm_struct *mm = vma->vm_mm;
struct rlimit *rlim = current->signal->rlim;
@@ -2165,7 +2164,7 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns
/* Stack limit test */
actual_size = size;
if (size && (vma->vm_flags & (VM_GROWSUP | VM_GROWSDOWN)))
- actual_size -= gap;
+ actual_size -= PAGE_SIZE;
if (actual_size > READ_ONCE(rlim[RLIMIT_STACK].rlim_cur))
return -ENOMEM;
@@ -2201,7 +2200,7 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns
* PA-RISC uses this for its stack; IA64 for its Register Backing Store.
* vma is the last one with address > vma->vm_end. Have to extend vma.
*/
-int expand_upwards(struct vm_area_struct *vma, unsigned long address, unsigned long gap)
+int expand_upwards(struct vm_area_struct *vma, unsigned long address)
{
struct mm_struct *mm = vma->vm_mm;
int error = 0;
@@ -2209,6 +2208,12 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address, unsigned l
if (!(vma->vm_flags & VM_GROWSUP))
return -EFAULT;
+ /* Guard against wrapping around to address 0. */
+ if (address < PAGE_ALIGN(address+4))
+ address = PAGE_ALIGN(address+4);
+ else
+ return -ENOMEM;
+
/* We must make sure the anon_vma is allocated. */
if (unlikely(anon_vma_prepare(vma)))
return -ENOMEM;
@@ -2229,7 +2234,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address, unsigned l
error = -ENOMEM;
if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
- error = acct_stack_growth(vma, size, grow, gap);
+ error = acct_stack_growth(vma, size, grow);
if (!error) {
/*
* vma_gap_update() doesn't support concurrent
@@ -2270,7 +2275,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address, unsigned l
* vma is the first one with address < vma->vm_start. Have to extend vma.
*/
int expand_downwards(struct vm_area_struct *vma,
- unsigned long address, unsigned long gap)
+ unsigned long address)
{
struct mm_struct *mm = vma->vm_mm;
int error;
@@ -2300,7 +2305,7 @@ int expand_downwards(struct vm_area_struct *vma,
error = -ENOMEM;
if (grow <= vma->vm_pgoff) {
- error = acct_stack_growth(vma, size, grow, gap);
+ error = acct_stack_growth(vma, size, grow);
if (!error) {
/*
* vma_gap_update() doesn't support concurrent
@@ -2334,72 +2339,29 @@ int expand_downwards(struct vm_area_struct *vma,
return error;
}
-/* enforced gap between the expanding stack and other mappings. */
-unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
-
/*
* Note how expand_stack() refuses to expand the stack all the way to
* abut the next virtual mapping, *unless* that mapping itself is also
- * a stack mapping. We want to leave room for a guard area, after all
+ * a stack mapping. We want to leave room for a guard page, after all
* (the guard page itself is not added here, that is done by the
* actual page faulting logic)
+ *
+ * This matches the behavior of the guard page logic (see mm/memory.c:
+ * check_stack_guard_page()), which only allows the guard page to be
+ * removed under these circumstances.
*/
#ifdef CONFIG_STACK_GROWSUP
-unsigned long expandable_stack_area(struct vm_area_struct *vma,
- unsigned long address, unsigned long *gap)
-{
- struct vm_area_struct *next = vma->vm_next;
- unsigned long guard_gap = stack_guard_gap;
- unsigned long guard_addr;
-
- address = ALIGN(address, PAGE_SIZE);;
- if (!next)
- goto out;
-
- if (next->vm_flags & VM_GROWSUP) {
- guard_gap = min(guard_gap, next->vm_start - address);
- goto out;
- }
-
- if (next->vm_start - address < guard_gap)
- return -ENOMEM;
-out:
- if (TASK_SIZE - address < guard_gap)
- guard_gap = TASK_SIZE - address;
- guard_addr = address + guard_gap;
- *gap = guard_gap;
-
- return guard_addr;
-}
-
int expand_stack(struct vm_area_struct *vma, unsigned long address)
{
- unsigned long gap;
-
- address = expandable_stack_area(vma, address, &gap);
- if (IS_ERR_VALUE(address))
- return -ENOMEM;
- return expand_upwards(vma, address, gap);
-}
-
-int stack_guard_area(struct vm_area_struct *vma, unsigned long address)
-{
struct vm_area_struct *next;
- if (!(vma->vm_flags & VM_GROWSUP))
- return 0;
-
- /*
- * strictly speaking there is a guard gap between disjoint stacks
- * but the gap is not canonical (it might be smaller) and it is
- * reasonably safe to assume that we can ignore that gap for stack
- * POPULATE or /proc/<pid>[s]maps purposes
- */
+ address &= PAGE_MASK;
next = vma->vm_next;
- if (next && next->vm_flags & VM_GROWSUP)
- return 0;
-
- return vma->vm_end - address <= stack_guard_gap;
+ if (next && next->vm_start == address + PAGE_SIZE) {
+ if (!(next->vm_flags & VM_GROWSUP))
+ return -ENOMEM;
+ }
+ return expand_upwards(vma, address);
}
struct vm_area_struct *
@@ -2418,73 +2380,17 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr)
return prev;
}
#else
-unsigned long expandable_stack_area(struct vm_area_struct *vma,
- unsigned long address, unsigned long *gap)
-{
- struct vm_area_struct *prev = vma->vm_prev;
- unsigned long guard_gap = stack_guard_gap;
- unsigned long guard_addr;
-
- address &= PAGE_MASK;
- if (!prev)
- goto out;
-
- /*
- * Is there a mapping abutting this one below?
- *
- * That's only ok if it's the same stack mapping
- * that has gotten split or there is sufficient gap
- * between mappings
- */
- if (prev->vm_flags & VM_GROWSDOWN) {
- guard_gap = min(guard_gap, address - prev->vm_end);
- goto out;
- }
-
- if (address - prev->vm_end < guard_gap)
- return -ENOMEM;
-
-out:
- /* make sure we won't underflow */
- if (address < mmap_min_addr)
- return -ENOMEM;
- if (address - mmap_min_addr < guard_gap)
- guard_gap = address - mmap_min_addr;
-
- guard_addr = address - guard_gap;
- *gap = guard_gap;
-
- return guard_addr;
-}
-
int expand_stack(struct vm_area_struct *vma, unsigned long address)
{
- unsigned long gap;
-
- address = expandable_stack_area(vma, address, &gap);
- if (IS_ERR_VALUE(address))
- return -ENOMEM;
- return expand_downwards(vma, address, gap);
-}
-
-int stack_guard_area(struct vm_area_struct *vma, unsigned long address)
-{
struct vm_area_struct *prev;
- if (!(vma->vm_flags & VM_GROWSDOWN))
- return 0;
-
- /*
- * strictly speaking there is a guard gap between disjoint stacks
- * but the gap is not canonical (it might be smaller) and it is
- * reasonably safe to assume that we can ignore that gap for stack
- * POPULATE or /proc/<pid>[s]maps purposes
- */
+ address &= PAGE_MASK;
prev = vma->vm_prev;
- if (prev && prev->vm_flags & VM_GROWSDOWN)
- return 0;
-
- return address - vma->vm_start < stack_guard_gap;
+ if (prev && prev->vm_end == address) {
+ if (!(prev->vm_flags & VM_GROWSDOWN))
+ return -ENOMEM;
+ }
+ return expand_downwards(vma, address);
}
struct vm_area_struct *
--
2.11.0
Reference in New Issue View Git Blame Copy Permalink