* [PATCH] f2fs: fix potential .flags overflow on 32bit architecture
@ 2020-03-22 10:13 Chao Yu
2020-03-22 12:14 ` Ondřej Jirman
0 siblings, 1 reply; 5+ messages in thread
From: Chao Yu @ 2020-03-22 10:13 UTC (permalink / raw)
To: jaegeuk; +Cc: linux-f2fs-devel, linux-kernel, Chao Yu
From: Chao Yu <yuchao0@huawei.com>
f2fs_inode_info.flags is unsigned long variable, it has 32 bits
in 32bit architecture, since we introduced FI_MMAP_FILE flag
when we support data compression, we may access memory cross
the border of .flags field, corrupting .i_sem field, result in
below deadlock.
To fix this issue, let's introduce .extra_flags to grab extra
space to store those new flags.
Call Trace:
__schedule+0x8d0/0x13fc
? mark_held_locks+0xac/0x100
schedule+0xcc/0x260
rwsem_down_write_slowpath+0x3ab/0x65d
down_write+0xc7/0xe0
f2fs_drop_nlink+0x3d/0x600 [f2fs]
f2fs_delete_inline_entry+0x300/0x440 [f2fs]
f2fs_delete_entry+0x3a1/0x7f0 [f2fs]
f2fs_unlink+0x500/0x790 [f2fs]
vfs_unlink+0x211/0x490
do_unlinkat+0x483/0x520
sys_unlink+0x4a/0x70
do_fast_syscall_32+0x12b/0x683
entry_SYSENTER_32+0xaa/0x102
Fixes: 4c8ff7095bef ("f2fs: support data compression")
Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
fs/f2fs/f2fs.h | 26 ++++++++++++++++++++------
fs/f2fs/inode.c | 1 +
2 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index fcafa68212eb..fcd22df2e9ca 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -695,6 +695,7 @@ struct f2fs_inode_info {
/* Use below internally in f2fs*/
unsigned long flags; /* use to pass per-file flags */
+ unsigned long extra_flags; /* extra flags */
struct rw_semaphore i_sem; /* protect fi info */
atomic_t dirty_pages; /* # of dirty pages */
f2fs_hash_t chash; /* hash value of given file name */
@@ -2569,7 +2570,7 @@ enum {
};
static inline void __mark_inode_dirty_flag(struct inode *inode,
- int flag, bool set)
+ unsigned long long flag, bool set)
{
switch (flag) {
case FI_INLINE_XATTR:
@@ -2588,20 +2589,33 @@ static inline void __mark_inode_dirty_flag(struct inode *inode,
static inline void set_inode_flag(struct inode *inode, int flag)
{
- if (!test_bit(flag, &F2FS_I(inode)->flags))
- set_bit(flag, &F2FS_I(inode)->flags);
+ if ((1 << flag) <= sizeof(unsigned long)) {
+ if (!test_bit(flag, &F2FS_I(inode)->flags))
+ set_bit(flag, &F2FS_I(inode)->flags);
+ } else {
+ if (!test_bit(flag - 32, &F2FS_I(inode)->extra_flags))
+ set_bit(flag - 32, &F2FS_I(inode)->extra_flags);
+ }
__mark_inode_dirty_flag(inode, flag, true);
}
static inline int is_inode_flag_set(struct inode *inode, int flag)
{
- return test_bit(flag, &F2FS_I(inode)->flags);
+ if ((1 << flag) <= sizeof(unsigned long))
+ return test_bit(flag, &F2FS_I(inode)->flags);
+ else
+ return test_bit(flag - 32, &F2FS_I(inode)->extra_flags);
}
static inline void clear_inode_flag(struct inode *inode, int flag)
{
- if (test_bit(flag, &F2FS_I(inode)->flags))
- clear_bit(flag, &F2FS_I(inode)->flags);
+ if ((1 << flag) <= sizeof(unsigned long)) {
+ if (test_bit(flag, &F2FS_I(inode)->flags))
+ clear_bit(flag, &F2FS_I(inode)->flags);
+ } else {
+ if (test_bit(flag - 32, &F2FS_I(inode)->extra_flags))
+ clear_bit(flag - 32, &F2FS_I(inode)->extra_flags);
+ }
__mark_inode_dirty_flag(inode, flag, false);
}
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 44e08bf2e2b4..ca924d7e0e30 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -363,6 +363,7 @@ static int do_read_inode(struct inode *inode)
if (S_ISREG(inode->i_mode))
fi->i_flags &= ~F2FS_PROJINHERIT_FL;
fi->flags = 0;
+ fi->extra_flags = 0;
fi->i_advise = ri->i_advise;
fi->i_pino = le32_to_cpu(ri->i_pino);
fi->i_dir_level = ri->i_dir_level;
--
2.22.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] f2fs: fix potential .flags overflow on 32bit architecture
2020-03-22 10:13 [PATCH] f2fs: fix potential .flags overflow on 32bit architecture Chao Yu
@ 2020-03-22 12:14 ` Ondřej Jirman
2020-03-22 13:18 ` Chao Yu
0 siblings, 1 reply; 5+ messages in thread
From: Ondřej Jirman @ 2020-03-22 12:14 UTC (permalink / raw)
To: Chao Yu; +Cc: jaegeuk, linux-f2fs-devel, linux-kernel, Chao Yu
Hello,
On Sun, Mar 22, 2020 at 06:13:27PM +0800, Chao Yu wrote:
> From: Chao Yu <yuchao0@huawei.com>
>
> f2fs_inode_info.flags is unsigned long variable, it has 32 bits
> in 32bit architecture, since we introduced FI_MMAP_FILE flag
> when we support data compression, we may access memory cross
> the border of .flags field, corrupting .i_sem field, result in
> below deadlock.
>
> To fix this issue, let's introduce .extra_flags to grab extra
> space to store those new flags.
>
> Call Trace:
> __schedule+0x8d0/0x13fc
> ? mark_held_locks+0xac/0x100
> schedule+0xcc/0x260
> rwsem_down_write_slowpath+0x3ab/0x65d
> down_write+0xc7/0xe0
> f2fs_drop_nlink+0x3d/0x600 [f2fs]
> f2fs_delete_inline_entry+0x300/0x440 [f2fs]
> f2fs_delete_entry+0x3a1/0x7f0 [f2fs]
> f2fs_unlink+0x500/0x790 [f2fs]
> vfs_unlink+0x211/0x490
> do_unlinkat+0x483/0x520
> sys_unlink+0x4a/0x70
> do_fast_syscall_32+0x12b/0x683
> entry_SYSENTER_32+0xaa/0x102
>
> Fixes: 4c8ff7095bef ("f2fs: support data compression")
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
> fs/f2fs/f2fs.h | 26 ++++++++++++++++++++------
> fs/f2fs/inode.c | 1 +
> 2 files changed, 21 insertions(+), 6 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index fcafa68212eb..fcd22df2e9ca 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -695,6 +695,7 @@ struct f2fs_inode_info {
>
> /* Use below internally in f2fs*/
> unsigned long flags; /* use to pass per-file flags */
> + unsigned long extra_flags; /* extra flags */
> struct rw_semaphore i_sem; /* protect fi info */
> atomic_t dirty_pages; /* # of dirty pages */
> f2fs_hash_t chash; /* hash value of given file name */
> @@ -2569,7 +2570,7 @@ enum {
> };
>
> static inline void __mark_inode_dirty_flag(struct inode *inode,
> - int flag, bool set)
> + unsigned long long flag, bool set)
> {
> switch (flag) {
> case FI_INLINE_XATTR:
> @@ -2588,20 +2589,33 @@ static inline void __mark_inode_dirty_flag(struct inode *inode,
>
> static inline void set_inode_flag(struct inode *inode, int flag)
> {
> - if (!test_bit(flag, &F2FS_I(inode)->flags))
> - set_bit(flag, &F2FS_I(inode)->flags);
> + if ((1 << flag) <= sizeof(unsigned long)) {
^ this is wrong. Maybe you meant flag <= BITS_PER_LONG
And ditto for the same checks below. Maybe you can make flags an array of
BIT_WORD(max_flag_value) + 1 and skip the branches altogether?
thank you and regards,
o.
> + if (!test_bit(flag, &F2FS_I(inode)->flags))
> + set_bit(flag, &F2FS_I(inode)->flags);
> + } else {
> + if (!test_bit(flag - 32, &F2FS_I(inode)->extra_flags))
> + set_bit(flag - 32, &F2FS_I(inode)->extra_flags);
> + }
> __mark_inode_dirty_flag(inode, flag, true);
> }
>
> static inline int is_inode_flag_set(struct inode *inode, int flag)
> {
> - return test_bit(flag, &F2FS_I(inode)->flags);
> + if ((1 << flag) <= sizeof(unsigned long))
> + return test_bit(flag, &F2FS_I(inode)->flags);
> + else
> + return test_bit(flag - 32, &F2FS_I(inode)->extra_flags);
> }
>
> static inline void clear_inode_flag(struct inode *inode, int flag)
> {
> - if (test_bit(flag, &F2FS_I(inode)->flags))
> - clear_bit(flag, &F2FS_I(inode)->flags);
> + if ((1 << flag) <= sizeof(unsigned long)) {
> + if (test_bit(flag, &F2FS_I(inode)->flags))
> + clear_bit(flag, &F2FS_I(inode)->flags);
> + } else {
> + if (test_bit(flag - 32, &F2FS_I(inode)->extra_flags))
> + clear_bit(flag - 32, &F2FS_I(inode)->extra_flags);
> + }
> __mark_inode_dirty_flag(inode, flag, false);
> }
>
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> index 44e08bf2e2b4..ca924d7e0e30 100644
> --- a/fs/f2fs/inode.c
> +++ b/fs/f2fs/inode.c
> @@ -363,6 +363,7 @@ static int do_read_inode(struct inode *inode)
> if (S_ISREG(inode->i_mode))
> fi->i_flags &= ~F2FS_PROJINHERIT_FL;
> fi->flags = 0;
> + fi->extra_flags = 0;
> fi->i_advise = ri->i_advise;
> fi->i_pino = le32_to_cpu(ri->i_pino);
> fi->i_dir_level = ri->i_dir_level;
> --
> 2.22.0
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] f2fs: fix potential .flags overflow on 32bit architecture
2020-03-22 12:14 ` Ondřej Jirman
@ 2020-03-22 13:18 ` Chao Yu
2020-03-22 15:30 ` Ondřej Jirman
0 siblings, 1 reply; 5+ messages in thread
From: Chao Yu @ 2020-03-22 13:18 UTC (permalink / raw)
To: Ondřej Jirman, jaegeuk, linux-f2fs-devel, linux-kernel, Chao Yu
Hi,
On 2020-3-22 20:14, Ondřej Jirman wrote:
> Hello,
>
> On Sun, Mar 22, 2020 at 06:13:27PM +0800, Chao Yu wrote:
>> From: Chao Yu <yuchao0@huawei.com>
>>
>> f2fs_inode_info.flags is unsigned long variable, it has 32 bits
>> in 32bit architecture, since we introduced FI_MMAP_FILE flag
>> when we support data compression, we may access memory cross
>> the border of .flags field, corrupting .i_sem field, result in
>> below deadlock.
>>
>> To fix this issue, let's introduce .extra_flags to grab extra
>> space to store those new flags.
>>
>> Call Trace:
>> __schedule+0x8d0/0x13fc
>> ? mark_held_locks+0xac/0x100
>> schedule+0xcc/0x260
>> rwsem_down_write_slowpath+0x3ab/0x65d
>> down_write+0xc7/0xe0
>> f2fs_drop_nlink+0x3d/0x600 [f2fs]
>> f2fs_delete_inline_entry+0x300/0x440 [f2fs]
>> f2fs_delete_entry+0x3a1/0x7f0 [f2fs]
>> f2fs_unlink+0x500/0x790 [f2fs]
>> vfs_unlink+0x211/0x490
>> do_unlinkat+0x483/0x520
>> sys_unlink+0x4a/0x70
>> do_fast_syscall_32+0x12b/0x683
>> entry_SYSENTER_32+0xaa/0x102
>>
>> Fixes: 4c8ff7095bef ("f2fs: support data compression")
>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>> ---
>> fs/f2fs/f2fs.h | 26 ++++++++++++++++++++------
>> fs/f2fs/inode.c | 1 +
>> 2 files changed, 21 insertions(+), 6 deletions(-)
>>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index fcafa68212eb..fcd22df2e9ca 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -695,6 +695,7 @@ struct f2fs_inode_info {
>>
>> /* Use below internally in f2fs*/
>> unsigned long flags; /* use to pass per-file flags */
>> + unsigned long extra_flags; /* extra flags */
>> struct rw_semaphore i_sem; /* protect fi info */
>> atomic_t dirty_pages; /* # of dirty pages */
>> f2fs_hash_t chash; /* hash value of given file name */
>> @@ -2569,7 +2570,7 @@ enum {
>> };
>>
>> static inline void __mark_inode_dirty_flag(struct inode *inode,
>> - int flag, bool set)
>> + unsigned long long flag, bool set)
>> {
>> switch (flag) {
>> case FI_INLINE_XATTR:
>> @@ -2588,20 +2589,33 @@ static inline void __mark_inode_dirty_flag(struct inode *inode,
>>
>> static inline void set_inode_flag(struct inode *inode, int flag)
>> {
>> - if (!test_bit(flag, &F2FS_I(inode)->flags))
>> - set_bit(flag, &F2FS_I(inode)->flags);
>> + if ((1 << flag) <= sizeof(unsigned long)) {
>
> ^ this is wrong. Maybe you meant flag <= BITS_PER_LONG
Oh, my bad, I meant that, thanks for pointing out this. :)
>
> And ditto for the same checks below. Maybe you can make flags an array of
> BIT_WORD(max_flag_value) + 1 and skip the branches altogether?
That will be better, let me revise this patch.
Thanks,
>
> thank you and regards,
> o.
>
>> + if (!test_bit(flag, &F2FS_I(inode)->flags))
>> + set_bit(flag, &F2FS_I(inode)->flags);
>> + } else {
>> + if (!test_bit(flag - 32, &F2FS_I(inode)->extra_flags))
>> + set_bit(flag - 32, &F2FS_I(inode)->extra_flags);
>> + }
>> __mark_inode_dirty_flag(inode, flag, true);
>> }
>>
>> static inline int is_inode_flag_set(struct inode *inode, int flag)
>> {
>> - return test_bit(flag, &F2FS_I(inode)->flags);
>> + if ((1 << flag) <= sizeof(unsigned long))
>> + return test_bit(flag, &F2FS_I(inode)->flags);
>> + else
>> + return test_bit(flag - 32, &F2FS_I(inode)->extra_flags);
>> }
>>
>> static inline void clear_inode_flag(struct inode *inode, int flag)
>> {
>> - if (test_bit(flag, &F2FS_I(inode)->flags))
>> - clear_bit(flag, &F2FS_I(inode)->flags);
>> + if ((1 << flag) <= sizeof(unsigned long)) {
>> + if (test_bit(flag, &F2FS_I(inode)->flags))
>> + clear_bit(flag, &F2FS_I(inode)->flags);
>> + } else {
>> + if (test_bit(flag - 32, &F2FS_I(inode)->extra_flags))
>> + clear_bit(flag - 32, &F2FS_I(inode)->extra_flags);
>> + }
>> __mark_inode_dirty_flag(inode, flag, false);
>> }
>>
>> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
>> index 44e08bf2e2b4..ca924d7e0e30 100644
>> --- a/fs/f2fs/inode.c
>> +++ b/fs/f2fs/inode.c
>> @@ -363,6 +363,7 @@ static int do_read_inode(struct inode *inode)
>> if (S_ISREG(inode->i_mode))
>> fi->i_flags &= ~F2FS_PROJINHERIT_FL;
>> fi->flags = 0;
>> + fi->extra_flags = 0;
>> fi->i_advise = ri->i_advise;
>> fi->i_pino = le32_to_cpu(ri->i_pino);
>> fi->i_dir_level = ri->i_dir_level;
>> --
>> 2.22.0
>>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] f2fs: fix potential .flags overflow on 32bit architecture
2020-03-22 13:18 ` Chao Yu
@ 2020-03-22 15:30 ` Ondřej Jirman
2020-03-23 1:15 ` Chao Yu
0 siblings, 1 reply; 5+ messages in thread
From: Ondřej Jirman @ 2020-03-22 15:30 UTC (permalink / raw)
To: Chao Yu; +Cc: jaegeuk, linux-f2fs-devel, linux-kernel, Chao Yu
On Sun, Mar 22, 2020 at 09:18:56PM +0800, Chao Yu wrote:
> Hi,
>
> On 2020-3-22 20:14, Ondřej Jirman wrote:
> > Hello,
> >
> > On Sun, Mar 22, 2020 at 06:13:27PM +0800, Chao Yu wrote:
> > > From: Chao Yu <yuchao0@huawei.com>
> > >
> > > f2fs_inode_info.flags is unsigned long variable, it has 32 bits
> > > in 32bit architecture, since we introduced FI_MMAP_FILE flag
> > > when we support data compression, we may access memory cross
> > > the border of .flags field, corrupting .i_sem field, result in
> > > below deadlock.
> > >
> > > To fix this issue, let's introduce .extra_flags to grab extra
> > > space to store those new flags.
> > >
> > > Call Trace:
> > > __schedule+0x8d0/0x13fc
> > > ? mark_held_locks+0xac/0x100
> > > schedule+0xcc/0x260
> > > rwsem_down_write_slowpath+0x3ab/0x65d
> > > down_write+0xc7/0xe0
> > > f2fs_drop_nlink+0x3d/0x600 [f2fs]
> > > f2fs_delete_inline_entry+0x300/0x440 [f2fs]
> > > f2fs_delete_entry+0x3a1/0x7f0 [f2fs]
> > > f2fs_unlink+0x500/0x790 [f2fs]
> > > vfs_unlink+0x211/0x490
> > > do_unlinkat+0x483/0x520
> > > sys_unlink+0x4a/0x70
> > > do_fast_syscall_32+0x12b/0x683
> > > entry_SYSENTER_32+0xaa/0x102
> > >
> > > Fixes: 4c8ff7095bef ("f2fs: support data compression")
> > > Signed-off-by: Chao Yu <yuchao0@huawei.com>
> > > ---
> > > fs/f2fs/f2fs.h | 26 ++++++++++++++++++++------
> > > fs/f2fs/inode.c | 1 +
> > > 2 files changed, 21 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > > index fcafa68212eb..fcd22df2e9ca 100644
> > > --- a/fs/f2fs/f2fs.h
> > > +++ b/fs/f2fs/f2fs.h
> > > @@ -695,6 +695,7 @@ struct f2fs_inode_info {
> > >
> > > /* Use below internally in f2fs*/
> > > unsigned long flags; /* use to pass per-file flags */
> > > + unsigned long extra_flags; /* extra flags */
> > > struct rw_semaphore i_sem; /* protect fi info */
> > > atomic_t dirty_pages; /* # of dirty pages */
> > > f2fs_hash_t chash; /* hash value of given file name */
> > > @@ -2569,7 +2570,7 @@ enum {
> > > };
> > >
> > > static inline void __mark_inode_dirty_flag(struct inode *inode,
> > > - int flag, bool set)
> > > + unsigned long long flag, bool set)
> > > {
> > > switch (flag) {
> > > case FI_INLINE_XATTR:
> > > @@ -2588,20 +2589,33 @@ static inline void __mark_inode_dirty_flag(struct inode *inode,
> > >
> > > static inline void set_inode_flag(struct inode *inode, int flag)
> > > {
> > > - if (!test_bit(flag, &F2FS_I(inode)->flags))
> > > - set_bit(flag, &F2FS_I(inode)->flags);
> > > + if ((1 << flag) <= sizeof(unsigned long)) {
> >
> > ^ this is wrong. Maybe you meant flag <= BITS_PER_LONG
>
> Oh, my bad, I meant that, thanks for pointing out this. :)
>
> >
> > And ditto for the same checks below. Maybe you can make flags an array of
> > BIT_WORD(max_flag_value) + 1 and skip the branches altogether?
I've found maybe a clearer macro for this:
https://elixir.bootlin.com/linux/latest/source/include/linux/bitops.h#L15
BITS_TO_LONGS(nr)
But it takes the number of bits in the bitmap, which would be
"max_flag_value + 1".
regards,
o.
> That will be better, let me revise this patch.
>
> Thanks,
>
> >
> > thank you and regards,
> > o.
> >
> > > + if (!test_bit(flag, &F2FS_I(inode)->flags))
> > > + set_bit(flag, &F2FS_I(inode)->flags);
> > > + } else {
> > > + if (!test_bit(flag - 32, &F2FS_I(inode)->extra_flags))
> > > + set_bit(flag - 32, &F2FS_I(inode)->extra_flags);
> > > + }
> > > __mark_inode_dirty_flag(inode, flag, true);
> > > }
> > >
> > > static inline int is_inode_flag_set(struct inode *inode, int flag)
> > > {
> > > - return test_bit(flag, &F2FS_I(inode)->flags);
> > > + if ((1 << flag) <= sizeof(unsigned long))
> > > + return test_bit(flag, &F2FS_I(inode)->flags);
> > > + else
> > > + return test_bit(flag - 32, &F2FS_I(inode)->extra_flags);
> > > }
> > >
> > > static inline void clear_inode_flag(struct inode *inode, int flag)
> > > {
> > > - if (test_bit(flag, &F2FS_I(inode)->flags))
> > > - clear_bit(flag, &F2FS_I(inode)->flags);
> > > + if ((1 << flag) <= sizeof(unsigned long)) {
> > > + if (test_bit(flag, &F2FS_I(inode)->flags))
> > > + clear_bit(flag, &F2FS_I(inode)->flags);
> > > + } else {
> > > + if (test_bit(flag - 32, &F2FS_I(inode)->extra_flags))
> > > + clear_bit(flag - 32, &F2FS_I(inode)->extra_flags);
> > > + }
> > > __mark_inode_dirty_flag(inode, flag, false);
> > > }
> > >
> > > diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> > > index 44e08bf2e2b4..ca924d7e0e30 100644
> > > --- a/fs/f2fs/inode.c
> > > +++ b/fs/f2fs/inode.c
> > > @@ -363,6 +363,7 @@ static int do_read_inode(struct inode *inode)
> > > if (S_ISREG(inode->i_mode))
> > > fi->i_flags &= ~F2FS_PROJINHERIT_FL;
> > > fi->flags = 0;
> > > + fi->extra_flags = 0;
> > > fi->i_advise = ri->i_advise;
> > > fi->i_pino = le32_to_cpu(ri->i_pino);
> > > fi->i_dir_level = ri->i_dir_level;
> > > --
> > > 2.22.0
> > >
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] f2fs: fix potential .flags overflow on 32bit architecture
2020-03-22 15:30 ` Ondřej Jirman
@ 2020-03-23 1:15 ` Chao Yu
0 siblings, 0 replies; 5+ messages in thread
From: Chao Yu @ 2020-03-23 1:15 UTC (permalink / raw)
To: Ondřej Jirman, Chao Yu, jaegeuk, linux-f2fs-devel, linux-kernel
On 2020/3/22 23:30, Ondřej Jirman wrote:
> On Sun, Mar 22, 2020 at 09:18:56PM +0800, Chao Yu wrote:
>> Hi,
>>
>> On 2020-3-22 20:14, Ondřej Jirman wrote:
>>> Hello,
>>>
>>> On Sun, Mar 22, 2020 at 06:13:27PM +0800, Chao Yu wrote:
>>>> From: Chao Yu <yuchao0@huawei.com>
>>>>
>>>> f2fs_inode_info.flags is unsigned long variable, it has 32 bits
>>>> in 32bit architecture, since we introduced FI_MMAP_FILE flag
>>>> when we support data compression, we may access memory cross
>>>> the border of .flags field, corrupting .i_sem field, result in
>>>> below deadlock.
>>>>
>>>> To fix this issue, let's introduce .extra_flags to grab extra
>>>> space to store those new flags.
>>>>
>>>> Call Trace:
>>>> __schedule+0x8d0/0x13fc
>>>> ? mark_held_locks+0xac/0x100
>>>> schedule+0xcc/0x260
>>>> rwsem_down_write_slowpath+0x3ab/0x65d
>>>> down_write+0xc7/0xe0
>>>> f2fs_drop_nlink+0x3d/0x600 [f2fs]
>>>> f2fs_delete_inline_entry+0x300/0x440 [f2fs]
>>>> f2fs_delete_entry+0x3a1/0x7f0 [f2fs]
>>>> f2fs_unlink+0x500/0x790 [f2fs]
>>>> vfs_unlink+0x211/0x490
>>>> do_unlinkat+0x483/0x520
>>>> sys_unlink+0x4a/0x70
>>>> do_fast_syscall_32+0x12b/0x683
>>>> entry_SYSENTER_32+0xaa/0x102
>>>>
>>>> Fixes: 4c8ff7095bef ("f2fs: support data compression")
>>>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>>>> ---
>>>> fs/f2fs/f2fs.h | 26 ++++++++++++++++++++------
>>>> fs/f2fs/inode.c | 1 +
>>>> 2 files changed, 21 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index fcafa68212eb..fcd22df2e9ca 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -695,6 +695,7 @@ struct f2fs_inode_info {
>>>>
>>>> /* Use below internally in f2fs*/
>>>> unsigned long flags; /* use to pass per-file flags */
>>>> + unsigned long extra_flags; /* extra flags */
>>>> struct rw_semaphore i_sem; /* protect fi info */
>>>> atomic_t dirty_pages; /* # of dirty pages */
>>>> f2fs_hash_t chash; /* hash value of given file name */
>>>> @@ -2569,7 +2570,7 @@ enum {
>>>> };
>>>>
>>>> static inline void __mark_inode_dirty_flag(struct inode *inode,
>>>> - int flag, bool set)
>>>> + unsigned long long flag, bool set)
>>>> {
>>>> switch (flag) {
>>>> case FI_INLINE_XATTR:
>>>> @@ -2588,20 +2589,33 @@ static inline void __mark_inode_dirty_flag(struct inode *inode,
>>>>
>>>> static inline void set_inode_flag(struct inode *inode, int flag)
>>>> {
>>>> - if (!test_bit(flag, &F2FS_I(inode)->flags))
>>>> - set_bit(flag, &F2FS_I(inode)->flags);
>>>> + if ((1 << flag) <= sizeof(unsigned long)) {
>>>
>>> ^ this is wrong. Maybe you meant flag <= BITS_PER_LONG
>>
>> Oh, my bad, I meant that, thanks for pointing out this. :)
>>
>>>
>>> And ditto for the same checks below. Maybe you can make flags an array of
>>> BIT_WORD(max_flag_value) + 1 and skip the branches altogether?
>
> I've found maybe a clearer macro for this:
>
> https://elixir.bootlin.com/linux/latest/source/include/linux/bitops.h#L15
>
> BITS_TO_LONGS(nr)
More clean, thanks, will send v3 soon.
Thanks,
>
> But it takes the number of bits in the bitmap, which would be
> "max_flag_value + 1".
>
> regards,
> o.
>
>> That will be better, let me revise this patch.
>>
>> Thanks,
>>
>>>
>>> thank you and regards,
>>> o.
>>>
>>>> + if (!test_bit(flag, &F2FS_I(inode)->flags))
>>>> + set_bit(flag, &F2FS_I(inode)->flags);
>>>> + } else {
>>>> + if (!test_bit(flag - 32, &F2FS_I(inode)->extra_flags))
>>>> + set_bit(flag - 32, &F2FS_I(inode)->extra_flags);
>>>> + }
>>>> __mark_inode_dirty_flag(inode, flag, true);
>>>> }
>>>>
>>>> static inline int is_inode_flag_set(struct inode *inode, int flag)
>>>> {
>>>> - return test_bit(flag, &F2FS_I(inode)->flags);
>>>> + if ((1 << flag) <= sizeof(unsigned long))
>>>> + return test_bit(flag, &F2FS_I(inode)->flags);
>>>> + else
>>>> + return test_bit(flag - 32, &F2FS_I(inode)->extra_flags);
>>>> }
>>>>
>>>> static inline void clear_inode_flag(struct inode *inode, int flag)
>>>> {
>>>> - if (test_bit(flag, &F2FS_I(inode)->flags))
>>>> - clear_bit(flag, &F2FS_I(inode)->flags);
>>>> + if ((1 << flag) <= sizeof(unsigned long)) {
>>>> + if (test_bit(flag, &F2FS_I(inode)->flags))
>>>> + clear_bit(flag, &F2FS_I(inode)->flags);
>>>> + } else {
>>>> + if (test_bit(flag - 32, &F2FS_I(inode)->extra_flags))
>>>> + clear_bit(flag - 32, &F2FS_I(inode)->extra_flags);
>>>> + }
>>>> __mark_inode_dirty_flag(inode, flag, false);
>>>> }
>>>>
>>>> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
>>>> index 44e08bf2e2b4..ca924d7e0e30 100644
>>>> --- a/fs/f2fs/inode.c
>>>> +++ b/fs/f2fs/inode.c
>>>> @@ -363,6 +363,7 @@ static int do_read_inode(struct inode *inode)
>>>> if (S_ISREG(inode->i_mode))
>>>> fi->i_flags &= ~F2FS_PROJINHERIT_FL;
>>>> fi->flags = 0;
>>>> + fi->extra_flags = 0;
>>>> fi->i_advise = ri->i_advise;
>>>> fi->i_pino = le32_to_cpu(ri->i_pino);
>>>> fi->i_dir_level = ri->i_dir_level;
>>>> --
>>>> 2.22.0
>>>>
> .
>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-03-23 1:15 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-22 10:13 [PATCH] f2fs: fix potential .flags overflow on 32bit architecture Chao Yu
2020-03-22 12:14 ` Ondřej Jirman
2020-03-22 13:18 ` Chao Yu
2020-03-22 15:30 ` Ondřej Jirman
2020-03-23 1:15 ` Chao Yu
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