The patch titled
Subject: kasan: detect negative size in memory operation function
has been removed from the -mm tree. Its filename was
kasan-detect-negative-size-in-memory-operation-function.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Walter Wu <walter-zh.wu@xxxxxxxxxxxx>
Subject: kasan: detect negative size in memory operation function
Patch series "fix the missing underflow in memory operation function", v4.
The patchset helps to produce a KASAN report when size is negative in
memory operation functions. It is helpful for programmer to solve an
undefined behavior issue. Patch 1 based on Dmitry's review and
suggestion, patch 2 is a test in order to verify the patch 1.
[1]https://bugzilla.kernel.org/show_bug.cgi?id=199341
[2]https://lore.kernel.org/linux-arm-kernel/20190927034338.15813-1-walter-zh.wu@xxxxxxxxxxxx/
This patch (of 2):
KASAN missed detecting size is a negative number in memset(), memcpy(),
and memmove(), it will cause out-of-bounds bug. So needs to be detected
by KASAN.
If size is a negative number, then it has a reason to be defined as
out-of-bounds bug type. Casting negative numbers to size_t would indeed
turn up as a large size_t and its value will be larger than ULONG_MAX/2,
so that this can qualify as out-of-bounds.
KASAN report is shown below:
BUG: KASAN: out-of-bounds in kmalloc_memmove_invalid_size+0x70/0xa0
Read of size 18446744073709551608 at addr ffffff8069660904 by task cat/72
CPU: 2 PID: 72 Comm: cat Not tainted 5.4.0-rc1-next-20191004ajb-00001-gdb8af2f372b2-dirty #1
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x0/0x288
show_stack+0x14/0x20
dump_stack+0x10c/0x164
print_address_description.isra.9+0x68/0x378
__kasan_report+0x164/0x1a0
kasan_report+0xc/0x18
check_memory_region+0x174/0x1d0
memmove+0x34/0x88
kmalloc_memmove_invalid_size+0x70/0xa0
[1] https://bugzilla.kernel.org/show_bug.cgi?id=199341
[cai@xxxxxx: fix -Wdeclaration-after-statement warn]
Link: http://lkml.kernel.org/r/1583509030-27939-1-git-send-email-cai@xxxxxx
[peterz@xxxxxxxxxxxxx: fix objtool warning]
Link: http://lkml.kernel.org/r/20200305095436.GV2596@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20191112065302.7015-1-walter-zh.wu@xxxxxxxxxxxx
Signed-off-by: Walter Wu <walter-zh.wu@xxxxxxxxxxxx>
Signed-off-by: Qian Cai <cai@xxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Suggested-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Reviewed-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Reviewed-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/kasan.h | 2 +-
mm/kasan/common.c | 26 +++++++++++++++++++-------
mm/kasan/generic.c | 9 +++++----
mm/kasan/generic_report.c | 11 +++++++++++
mm/kasan/kasan.h | 2 +-
mm/kasan/report.c | 5 +----
mm/kasan/tags.c | 9 +++++----
mm/kasan/tags_report.c | 11 +++++++++++
8 files changed, 54 insertions(+), 21 deletions(-)
--- a/include/linux/kasan.h~kasan-detect-negative-size-in-memory-operation-function
+++ a/include/linux/kasan.h
@@ -190,7 +190,7 @@ void kasan_init_tags(void);
void *kasan_reset_tag(const void *addr);
-void kasan_report(unsigned long addr, size_t size,
+bool kasan_report(unsigned long addr, size_t size,
bool is_write, unsigned long ip);
#else /* CONFIG_KASAN_SW_TAGS */
--- a/mm/kasan/common.c~kasan-detect-negative-size-in-memory-operation-function
+++ a/mm/kasan/common.c
@@ -105,7 +105,8 @@ EXPORT_SYMBOL(__kasan_check_write);
#undef memset
void *memset(void *addr, int c, size_t len)
{
- check_memory_region((unsigned long)addr, len, true, _RET_IP_);
+ if (!check_memory_region((unsigned long)addr, len, true, _RET_IP_))
+ return NULL;
return __memset(addr, c, len);
}
@@ -114,8 +115,9 @@ void *memset(void *addr, int c, size_t l
#undef memmove
void *memmove(void *dest, const void *src, size_t len)
{
- check_memory_region((unsigned long)src, len, false, _RET_IP_);
- check_memory_region((unsigned long)dest, len, true, _RET_IP_);
+ if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) ||
+ !check_memory_region((unsigned long)dest, len, true, _RET_IP_))
+ return NULL;
return __memmove(dest, src, len);
}
@@ -124,8 +126,9 @@ void *memmove(void *dest, const void *sr
#undef memcpy
void *memcpy(void *dest, const void *src, size_t len)
{
- check_memory_region((unsigned long)src, len, false, _RET_IP_);
- check_memory_region((unsigned long)dest, len, true, _RET_IP_);
+ if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) ||
+ !check_memory_region((unsigned long)dest, len, true, _RET_IP_))
+ return NULL;
return __memcpy(dest, src, len);
}
@@ -634,12 +637,21 @@ void kasan_free_shadow(const struct vm_s
#endif
extern void __kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip);
+extern bool report_enabled(void);
-void kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip)
+bool kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip)
{
unsigned long flags = user_access_save();
- __kasan_report(addr, size, is_write, ip);
+ bool ret = false;
+
+ if (likely(report_enabled())) {
+ __kasan_report(addr, size, is_write, ip);
+ ret = true;
+ }
+
user_access_restore(flags);
+
+ return ret;
}
#ifdef CONFIG_MEMORY_HOTPLUG
--- a/mm/kasan/generic.c~kasan-detect-negative-size-in-memory-operation-function
+++ a/mm/kasan/generic.c
@@ -173,17 +173,18 @@ static __always_inline bool check_memory
if (unlikely(size == 0))
return true;
+ if (unlikely(addr + size < addr))
+ return !kasan_report(addr, size, write, ret_ip);
+
if (unlikely((void *)addr <
kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
- kasan_report(addr, size, write, ret_ip);
- return false;
+ return !kasan_report(addr, size, write, ret_ip);
}
if (likely(!memory_is_poisoned(addr, size)))
return true;
- kasan_report(addr, size, write, ret_ip);
- return false;
+ return !kasan_report(addr, size, write, ret_ip);
}
bool check_memory_region(unsigned long addr, size_t size, bool write,
--- a/mm/kasan/generic_report.c~kasan-detect-negative-size-in-memory-operation-function
+++ a/mm/kasan/generic_report.c
@@ -110,6 +110,17 @@ static const char *get_wild_bug_type(str
const char *get_bug_type(struct kasan_access_info *info)
{
+ /*
+ * If access_size is a negative number, then it has reason to be
+ * defined as out-of-bounds bug type.
+ *
+ * Casting negative numbers to size_t would indeed turn up as
+ * a large size_t and its value will be larger than ULONG_MAX/2,
+ * so that this can qualify as out-of-bounds.
+ */
+ if (info->access_addr + info->access_size < info->access_addr)
+ return "out-of-bounds";
+
if (addr_has_shadow(info->access_addr))
return get_shadow_bug_type(info);
return get_wild_bug_type(info);
--- a/mm/kasan/kasan.h~kasan-detect-negative-size-in-memory-operation-function
+++ a/mm/kasan/kasan.h
@@ -153,7 +153,7 @@ bool check_memory_region(unsigned long a
void *find_first_bad_addr(void *addr, size_t size);
const char *get_bug_type(struct kasan_access_info *info);
-void kasan_report(unsigned long addr, size_t size,
+bool kasan_report(unsigned long addr, size_t size,
bool is_write, unsigned long ip);
void kasan_report_invalid_free(void *object, unsigned long ip);
--- a/mm/kasan/report.c~kasan-detect-negative-size-in-memory-operation-function
+++ a/mm/kasan/report.c
@@ -446,7 +446,7 @@ static void print_shadow_for_address(con
}
}
-static bool report_enabled(void)
+bool report_enabled(void)
{
if (current->kasan_depth)
return false;
@@ -478,9 +478,6 @@ void __kasan_report(unsigned long addr,
void *untagged_addr;
unsigned long flags;
- if (likely(!report_enabled()))
- return;
-
disable_trace_on_warning();
tagged_addr = (void *)addr;
--- a/mm/kasan/tags.c~kasan-detect-negative-size-in-memory-operation-function
+++ a/mm/kasan/tags.c
@@ -86,6 +86,9 @@ bool check_memory_region(unsigned long a
if (unlikely(size == 0))
return true;
+ if (unlikely(addr + size < addr))
+ return !kasan_report(addr, size, write, ret_ip);
+
tag = get_tag((const void *)addr);
/*
@@ -111,15 +114,13 @@ bool check_memory_region(unsigned long a
untagged_addr = reset_tag((const void *)addr);
if (unlikely(untagged_addr <
kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
- kasan_report(addr, size, write, ret_ip);
- return false;
+ return !kasan_report(addr, size, write, ret_ip);
}
shadow_first = kasan_mem_to_shadow(untagged_addr);
shadow_last = kasan_mem_to_shadow(untagged_addr + size - 1);
for (shadow = shadow_first; shadow <= shadow_last; shadow++) {
if (*shadow != tag) {
- kasan_report(addr, size, write, ret_ip);
- return false;
+ return !kasan_report(addr, size, write, ret_ip);
}
}
--- a/mm/kasan/tags_report.c~kasan-detect-negative-size-in-memory-operation-function
+++ a/mm/kasan/tags_report.c
@@ -60,6 +60,17 @@ const char *get_bug_type(struct kasan_ac
}
#endif
+ /*
+ * If access_size is a negative number, then it has reason to be
+ * defined as out-of-bounds bug type.
+ *
+ * Casting negative numbers to size_t would indeed turn up as
+ * a large size_t and its value will be larger than ULONG_MAX/2,
+ * so that this can qualify as out-of-bounds.
+ */
+ if (info->access_addr + info->access_size < info->access_addr)
+ return "out-of-bounds";
+
return "invalid-access";
}
_
Patches currently in -mm which might be from walter-zh.wu@xxxxxxxxxxxx are
