Re: [PATCH] f2fs: allocate buffer for decrypting filename to avoid panic
Hi Eric, Yunlong,
On 2018/2/25 2:32, Eric Biggers wrote:
> Hi Yunlong,
>
> On Sat, Feb 24, 2018 at 05:14:58PM +0800, Yunlong Song wrote:
>> In some platforms (such as arm), high memory is used, then the
>> decrypting filename will cause panic, the reason see commit
>> 569cf1876a32e574ba8a7fb825cd91bafd003882 ("f2fs crypto: allocate buffer
>> for decrypting filename"):
>>
>> We got dentry pages from high_mem, and its address space directly goes into
>> the
>> decryption path via f2fs_fname_disk_to_usr.
>> But, sg_init_one assumes the address is not from high_mem, so we can get
>> this
>> panic since it doesn't call kmap_high but kunmap_high is triggered at the
>> end.
>>
>> kernel BUG at ../../../../../../kernel/mm/highmem.c:290!
>> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
>> ...
>> (kunmap_high+0xb0/0xb8) from [] (__kunmap_atomic+0xa0/0xa4)
>> (__kunmap_atomic+0xa0/0xa4) from []
>> (blkcipher_walk_done+0x128/0x1ec)
>> (blkcipher_walk_done+0x128/0x1ec) from []
>> (crypto_cbc_decrypt+0xc0/0x170)
>> (crypto_cbc_decrypt+0xc0/0x170) from []
>> (crypto_cts_decrypt+0xc0/0x114)
>> (crypto_cts_decrypt+0xc0/0x114) from [] (async_decrypt+0x40/0x48)
>> (async_decrypt+0x40/0x48) from []
>> (f2fs_fname_disk_to_usr+0x124/0x304)
>> (f2fs_fname_disk_to_usr+0x124/0x304) from []
>> (f2fs_fill_dentries+0xac/0x188)
>> (f2fs_fill_dentries+0xac/0x188) from []
>> (f2fs_readdir+0x1f0/0x300)
>> (f2fs_readdir+0x1f0/0x300) from [] (vfs_readdir+0x90/0xb4)
>> (vfs_readdir+0x90/0xb4) from [] (SyS_getdents64+0x64/0xcc)
>> (SyS_getdents64+0x64/0xcc) from [] (ret_fast_syscall+0x0/0x30)
>>
>> Howerver, later patches:
>> commit 922ec355f86365388203672119b5bca346a45085 ("f2fs crypto: avoid
>> unneeded memory allocation when {en/de}crypting symlink")
>> commit e06f86e61d7a67fe6e826010f57aa39c674f4b1b ("f2fs crypto: avoid
>> unneeded memory allocation in ->readdir")
>>
>> reverts the codes, which causes panic again in arm, so let's add the old
>> patch again.
>>
>> Signed-off-by: Yunlong Song
>> ---
>> fs/f2fs/dir.c | 7 +++
>> fs/f2fs/namei.c | 10 +-
>> 2 files changed, 16 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
>> index f00b5ed..c0cf3e7b 100644
>> --- a/fs/f2fs/dir.c
>> +++ b/fs/f2fs/dir.c
>> @@ -825,9 +825,16 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct
>> f2fs_dentry_ptr *d,
>> int save_len = fstr->len;
>> int err;
>>
>> +de_name.name = kmalloc(de_name.len, GFP_NOFS);
>> +if (!de_name.name)
>> +return -ENOMEM;
>> +
>> +memcpy(de_name.name, d->filename[bit_pos], de_name.len);
>> +
>> err = fscrypt_fname_disk_to_usr(d->inode,
>> (u32)de->hash_code, 0,
>> _name, fstr);
>> +kfree(de_name.name);
>> if (err)
>> return err;
>>
>> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
>> index c4c94c7..2cb70c1 100644
>> --- a/fs/f2fs/namei.c
>> +++ b/fs/f2fs/namei.c
>> @@ -1170,8 +1170,13 @@ static const char *f2fs_encrypted_get_link(struct
>> dentry *dentry,
>>
>> /* Symlink is encrypted */
>> sd = (struct fscrypt_symlink_data *)caddr;
>> -cstr.name = sd->encrypted_path;
>> cstr.len = le16_to_cpu(sd->len);
>> +cstr.name = kmalloc(cstr.len, GFP_NOFS);
>> +if (!cstr.name) {
>> +res = -ENOMEM;
>> +goto errout;
>> +}
>> +memcpy(cstr.name, sd->encrypted_path, cstr.len);
>>
>> /* this is broken symlink case */
>> if (unlikely(cstr.len == 0)) {
>> @@ -1198,6 +1203,8 @@ static const char *f2fs_encrypted_get_link(struct
>> dentry *dentry,
>> goto errout;
>> }
>>
>> +kfree(cstr.name);
>> +
>> paddr = pstr.name;
>>
>> /* Null-terminate the name */
>> @@ -1207,6 +1214,7 @@ static const char *f2fs_encrypted_get_link(struct
>> dentry *dentry,
>> set_delayed_call(done, kfree_link, paddr);
>> return paddr;
>> errout:
>> +kfree(cstr.name);
>> fscrypt_fname_free_buffer();
>> put_page(cpage);
>> return ERR_PTR(res);
>> --
>> 1.8.5.2
>>
>
> The pagecache for symlinks in f2fs already uses lowmem only, so the change to
> ->get_link() isn't needed. Also that part of the patch doesn't apply to
> upstream.
>
> For directories we may need your fix. Note: kmalloc + memcpy should be
> replaced
> with kmemdup. But alternatively, directory pages could be restricted to
> lowmem
I'd like to suggest to use f2fs_kmalloc, so that we can deploy memory allocation
failure injection functionality in all places of f2fs, which can help to check
error handling in those places.
Thanks,
> which would match ext4.
>
> Eric
>
> .
>
Re: [PATCH] f2fs: allocate buffer for decrypting filename to avoid panic
Hi Eric, Yunlong,
On 2018/2/25 2:32, Eric Biggers wrote:
> Hi Yunlong,
>
> On Sat, Feb 24, 2018 at 05:14:58PM +0800, Yunlong Song wrote:
>> In some platforms (such as arm), high memory is used, then the
>> decrypting filename will cause panic, the reason see commit
>> 569cf1876a32e574ba8a7fb825cd91bafd003882 ("f2fs crypto: allocate buffer
>> for decrypting filename"):
>>
>> We got dentry pages from high_mem, and its address space directly goes into
>> the
>> decryption path via f2fs_fname_disk_to_usr.
>> But, sg_init_one assumes the address is not from high_mem, so we can get
>> this
>> panic since it doesn't call kmap_high but kunmap_high is triggered at the
>> end.
>>
>> kernel BUG at ../../../../../../kernel/mm/highmem.c:290!
>> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
>> ...
>> (kunmap_high+0xb0/0xb8) from [] (__kunmap_atomic+0xa0/0xa4)
>> (__kunmap_atomic+0xa0/0xa4) from []
>> (blkcipher_walk_done+0x128/0x1ec)
>> (blkcipher_walk_done+0x128/0x1ec) from []
>> (crypto_cbc_decrypt+0xc0/0x170)
>> (crypto_cbc_decrypt+0xc0/0x170) from []
>> (crypto_cts_decrypt+0xc0/0x114)
>> (crypto_cts_decrypt+0xc0/0x114) from [] (async_decrypt+0x40/0x48)
>> (async_decrypt+0x40/0x48) from []
>> (f2fs_fname_disk_to_usr+0x124/0x304)
>> (f2fs_fname_disk_to_usr+0x124/0x304) from []
>> (f2fs_fill_dentries+0xac/0x188)
>> (f2fs_fill_dentries+0xac/0x188) from []
>> (f2fs_readdir+0x1f0/0x300)
>> (f2fs_readdir+0x1f0/0x300) from [] (vfs_readdir+0x90/0xb4)
>> (vfs_readdir+0x90/0xb4) from [] (SyS_getdents64+0x64/0xcc)
>> (SyS_getdents64+0x64/0xcc) from [] (ret_fast_syscall+0x0/0x30)
>>
>> Howerver, later patches:
>> commit 922ec355f86365388203672119b5bca346a45085 ("f2fs crypto: avoid
>> unneeded memory allocation when {en/de}crypting symlink")
>> commit e06f86e61d7a67fe6e826010f57aa39c674f4b1b ("f2fs crypto: avoid
>> unneeded memory allocation in ->readdir")
>>
>> reverts the codes, which causes panic again in arm, so let's add the old
>> patch again.
>>
>> Signed-off-by: Yunlong Song
>> ---
>> fs/f2fs/dir.c | 7 +++
>> fs/f2fs/namei.c | 10 +-
>> 2 files changed, 16 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
>> index f00b5ed..c0cf3e7b 100644
>> --- a/fs/f2fs/dir.c
>> +++ b/fs/f2fs/dir.c
>> @@ -825,9 +825,16 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct
>> f2fs_dentry_ptr *d,
>> int save_len = fstr->len;
>> int err;
>>
>> +de_name.name = kmalloc(de_name.len, GFP_NOFS);
>> +if (!de_name.name)
>> +return -ENOMEM;
>> +
>> +memcpy(de_name.name, d->filename[bit_pos], de_name.len);
>> +
>> err = fscrypt_fname_disk_to_usr(d->inode,
>> (u32)de->hash_code, 0,
>> _name, fstr);
>> +kfree(de_name.name);
>> if (err)
>> return err;
>>
>> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
>> index c4c94c7..2cb70c1 100644
>> --- a/fs/f2fs/namei.c
>> +++ b/fs/f2fs/namei.c
>> @@ -1170,8 +1170,13 @@ static const char *f2fs_encrypted_get_link(struct
>> dentry *dentry,
>>
>> /* Symlink is encrypted */
>> sd = (struct fscrypt_symlink_data *)caddr;
>> -cstr.name = sd->encrypted_path;
>> cstr.len = le16_to_cpu(sd->len);
>> +cstr.name = kmalloc(cstr.len, GFP_NOFS);
>> +if (!cstr.name) {
>> +res = -ENOMEM;
>> +goto errout;
>> +}
>> +memcpy(cstr.name, sd->encrypted_path, cstr.len);
>>
>> /* this is broken symlink case */
>> if (unlikely(cstr.len == 0)) {
>> @@ -1198,6 +1203,8 @@ static const char *f2fs_encrypted_get_link(struct
>> dentry *dentry,
>> goto errout;
>> }
>>
>> +kfree(cstr.name);
>> +
>> paddr = pstr.name;
>>
>> /* Null-terminate the name */
>> @@ -1207,6 +1214,7 @@ static const char *f2fs_encrypted_get_link(struct
>> dentry *dentry,
>> set_delayed_call(done, kfree_link, paddr);
>> return paddr;
>> errout:
>> +kfree(cstr.name);
>> fscrypt_fname_free_buffer();
>> put_page(cpage);
>> return ERR_PTR(res);
>> --
>> 1.8.5.2
>>
>
> The pagecache for symlinks in f2fs already uses lowmem only, so the change to
> ->get_link() isn't needed. Also that part of the patch doesn't apply to
> upstream.
>
> For directories we may need your fix. Note: kmalloc + memcpy should be
> replaced
> with kmemdup. But alternatively, directory pages could be restricted to
> lowmem
I'd like to suggest to use f2fs_kmalloc, so that we can deploy memory allocation
failure injection functionality in all places of f2fs, which can help to check
error handling in those places.
Thanks,
> which would match ext4.
>
> Eric
>
> .
>
Re: [PATCH] f2fs: allocate buffer for decrypting filename to avoid panic
Hi, Eric,
Thanks for your review, I have removed the symlink part and use
kmemdup instead. As for directory pages restricted to lowmem, I am
not sure whether it is proper for f2fs, since the directory structures
of f2fs are different from ext4. So I just keep its old kmap.
On 2018/2/25 2:32, Eric Biggers wrote:
Hi Yunlong,
On Sat, Feb 24, 2018 at 05:14:58PM +0800, Yunlong Song wrote:
In some platforms (such as arm), high memory is used, then the
decrypting filename will cause panic, the reason see commit
569cf1876a32e574ba8a7fb825cd91bafd003882 ("f2fs crypto: allocate buffer
for decrypting filename"):
We got dentry pages from high_mem, and its address space directly goes into
the
decryption path via f2fs_fname_disk_to_usr.
But, sg_init_one assumes the address is not from high_mem, so we can get this
panic since it doesn't call kmap_high but kunmap_high is triggered at the end.
kernel BUG at ../../../../../../kernel/mm/highmem.c:290!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
...
(kunmap_high+0xb0/0xb8) from [] (__kunmap_atomic+0xa0/0xa4)
(__kunmap_atomic+0xa0/0xa4) from []
(blkcipher_walk_done+0x128/0x1ec)
(blkcipher_walk_done+0x128/0x1ec) from []
(crypto_cbc_decrypt+0xc0/0x170)
(crypto_cbc_decrypt+0xc0/0x170) from []
(crypto_cts_decrypt+0xc0/0x114)
(crypto_cts_decrypt+0xc0/0x114) from [] (async_decrypt+0x40/0x48)
(async_decrypt+0x40/0x48) from []
(f2fs_fname_disk_to_usr+0x124/0x304)
(f2fs_fname_disk_to_usr+0x124/0x304) from []
(f2fs_fill_dentries+0xac/0x188)
(f2fs_fill_dentries+0xac/0x188) from [] (f2fs_readdir+0x1f0/0x300)
(f2fs_readdir+0x1f0/0x300) from [] (vfs_readdir+0x90/0xb4)
(vfs_readdir+0x90/0xb4) from [] (SyS_getdents64+0x64/0xcc)
(SyS_getdents64+0x64/0xcc) from [] (ret_fast_syscall+0x0/0x30)
Howerver, later patches:
commit 922ec355f86365388203672119b5bca346a45085 ("f2fs crypto: avoid
unneeded memory allocation when {en/de}crypting symlink")
commit e06f86e61d7a67fe6e826010f57aa39c674f4b1b ("f2fs crypto: avoid
unneeded memory allocation in ->readdir")
reverts the codes, which causes panic again in arm, so let's add the old
patch again.
Signed-off-by: Yunlong Song
---
fs/f2fs/dir.c | 7 +++
fs/f2fs/namei.c | 10 +-
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index f00b5ed..c0cf3e7b 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -825,9 +825,16 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct
f2fs_dentry_ptr *d,
int save_len = fstr->len;
int err;
+ de_name.name = kmalloc(de_name.len, GFP_NOFS);
+ if (!de_name.name)
+ return -ENOMEM;
+
+ memcpy(de_name.name, d->filename[bit_pos], de_name.len);
+
err = fscrypt_fname_disk_to_usr(d->inode,
(u32)de->hash_code, 0,
_name, fstr);
+ kfree(de_name.name);
if (err)
return err;
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index c4c94c7..2cb70c1 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -1170,8 +1170,13 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
/* Symlink is encrypted */
sd = (struct fscrypt_symlink_data *)caddr;
- cstr.name = sd->encrypted_path;
cstr.len = le16_to_cpu(sd->len);
+ cstr.name = kmalloc(cstr.len, GFP_NOFS);
+ if (!cstr.name) {
+ res = -ENOMEM;
+ goto errout;
+ }
+ memcpy(cstr.name, sd->encrypted_path, cstr.len);
/* this is broken symlink case */
if (unlikely(cstr.len == 0)) {
@@ -1198,6 +1203,8 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
goto errout;
}
+ kfree(cstr.name);
+
paddr = pstr.name;
/* Null-terminate the name */
@@ -1207,6 +1214,7 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
set_delayed_call(done, kfree_link, paddr);
return paddr;
errout:
+ kfree(cstr.name);
fscrypt_fname_free_buffer();
put_page(cpage);
return ERR_PTR(res);
--
1.8.5.2
The pagecache for symlinks in f2fs already uses lowmem only, so the change to
->get_link() isn't needed. Also that part of the patch doesn't apply to
upstream.
For directories we may need your fix. Note: kmalloc + memcpy should be replaced
with kmemdup. But alternatively, directory pages could be restricted to lowmem
which would match ext4.
Eric
.
--
Thanks,
Yunlong Song
Re: [PATCH] f2fs: allocate buffer for decrypting filename to avoid panic
Hi, Eric,
Thanks for your review, I have removed the symlink part and use
kmemdup instead. As for directory pages restricted to lowmem, I am
not sure whether it is proper for f2fs, since the directory structures
of f2fs are different from ext4. So I just keep its old kmap.
On 2018/2/25 2:32, Eric Biggers wrote:
Hi Yunlong,
On Sat, Feb 24, 2018 at 05:14:58PM +0800, Yunlong Song wrote:
In some platforms (such as arm), high memory is used, then the
decrypting filename will cause panic, the reason see commit
569cf1876a32e574ba8a7fb825cd91bafd003882 ("f2fs crypto: allocate buffer
for decrypting filename"):
We got dentry pages from high_mem, and its address space directly goes into
the
decryption path via f2fs_fname_disk_to_usr.
But, sg_init_one assumes the address is not from high_mem, so we can get this
panic since it doesn't call kmap_high but kunmap_high is triggered at the end.
kernel BUG at ../../../../../../kernel/mm/highmem.c:290!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
...
(kunmap_high+0xb0/0xb8) from [] (__kunmap_atomic+0xa0/0xa4)
(__kunmap_atomic+0xa0/0xa4) from []
(blkcipher_walk_done+0x128/0x1ec)
(blkcipher_walk_done+0x128/0x1ec) from []
(crypto_cbc_decrypt+0xc0/0x170)
(crypto_cbc_decrypt+0xc0/0x170) from []
(crypto_cts_decrypt+0xc0/0x114)
(crypto_cts_decrypt+0xc0/0x114) from [] (async_decrypt+0x40/0x48)
(async_decrypt+0x40/0x48) from []
(f2fs_fname_disk_to_usr+0x124/0x304)
(f2fs_fname_disk_to_usr+0x124/0x304) from []
(f2fs_fill_dentries+0xac/0x188)
(f2fs_fill_dentries+0xac/0x188) from [] (f2fs_readdir+0x1f0/0x300)
(f2fs_readdir+0x1f0/0x300) from [] (vfs_readdir+0x90/0xb4)
(vfs_readdir+0x90/0xb4) from [] (SyS_getdents64+0x64/0xcc)
(SyS_getdents64+0x64/0xcc) from [] (ret_fast_syscall+0x0/0x30)
Howerver, later patches:
commit 922ec355f86365388203672119b5bca346a45085 ("f2fs crypto: avoid
unneeded memory allocation when {en/de}crypting symlink")
commit e06f86e61d7a67fe6e826010f57aa39c674f4b1b ("f2fs crypto: avoid
unneeded memory allocation in ->readdir")
reverts the codes, which causes panic again in arm, so let's add the old
patch again.
Signed-off-by: Yunlong Song
---
fs/f2fs/dir.c | 7 +++
fs/f2fs/namei.c | 10 +-
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index f00b5ed..c0cf3e7b 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -825,9 +825,16 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct
f2fs_dentry_ptr *d,
int save_len = fstr->len;
int err;
+ de_name.name = kmalloc(de_name.len, GFP_NOFS);
+ if (!de_name.name)
+ return -ENOMEM;
+
+ memcpy(de_name.name, d->filename[bit_pos], de_name.len);
+
err = fscrypt_fname_disk_to_usr(d->inode,
(u32)de->hash_code, 0,
_name, fstr);
+ kfree(de_name.name);
if (err)
return err;
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index c4c94c7..2cb70c1 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -1170,8 +1170,13 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
/* Symlink is encrypted */
sd = (struct fscrypt_symlink_data *)caddr;
- cstr.name = sd->encrypted_path;
cstr.len = le16_to_cpu(sd->len);
+ cstr.name = kmalloc(cstr.len, GFP_NOFS);
+ if (!cstr.name) {
+ res = -ENOMEM;
+ goto errout;
+ }
+ memcpy(cstr.name, sd->encrypted_path, cstr.len);
/* this is broken symlink case */
if (unlikely(cstr.len == 0)) {
@@ -1198,6 +1203,8 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
goto errout;
}
+ kfree(cstr.name);
+
paddr = pstr.name;
/* Null-terminate the name */
@@ -1207,6 +1214,7 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
set_delayed_call(done, kfree_link, paddr);
return paddr;
errout:
+ kfree(cstr.name);
fscrypt_fname_free_buffer();
put_page(cpage);
return ERR_PTR(res);
--
1.8.5.2
The pagecache for symlinks in f2fs already uses lowmem only, so the change to
->get_link() isn't needed. Also that part of the patch doesn't apply to
upstream.
For directories we may need your fix. Note: kmalloc + memcpy should be replaced
with kmemdup. But alternatively, directory pages could be restricted to lowmem
which would match ext4.
Eric
.
--
Thanks,
Yunlong Song
Re: [PATCH] f2fs: allocate buffer for decrypting filename to avoid panic
Hi Yunlong,
On Sat, Feb 24, 2018 at 05:14:58PM +0800, Yunlong Song wrote:
> In some platforms (such as arm), high memory is used, then the
> decrypting filename will cause panic, the reason see commit
> 569cf1876a32e574ba8a7fb825cd91bafd003882 ("f2fs crypto: allocate buffer
> for decrypting filename"):
>
> We got dentry pages from high_mem, and its address space directly goes into
> the
> decryption path via f2fs_fname_disk_to_usr.
> But, sg_init_one assumes the address is not from high_mem, so we can get this
> panic since it doesn't call kmap_high but kunmap_high is triggered at the
> end.
>
> kernel BUG at ../../../../../../kernel/mm/highmem.c:290!
> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
> ...
> (kunmap_high+0xb0/0xb8) from [] (__kunmap_atomic+0xa0/0xa4)
> (__kunmap_atomic+0xa0/0xa4) from []
> (blkcipher_walk_done+0x128/0x1ec)
> (blkcipher_walk_done+0x128/0x1ec) from []
> (crypto_cbc_decrypt+0xc0/0x170)
> (crypto_cbc_decrypt+0xc0/0x170) from []
> (crypto_cts_decrypt+0xc0/0x114)
> (crypto_cts_decrypt+0xc0/0x114) from [] (async_decrypt+0x40/0x48)
> (async_decrypt+0x40/0x48) from []
> (f2fs_fname_disk_to_usr+0x124/0x304)
> (f2fs_fname_disk_to_usr+0x124/0x304) from []
> (f2fs_fill_dentries+0xac/0x188)
> (f2fs_fill_dentries+0xac/0x188) from [] (f2fs_readdir+0x1f0/0x300)
> (f2fs_readdir+0x1f0/0x300) from [] (vfs_readdir+0x90/0xb4)
> (vfs_readdir+0x90/0xb4) from [] (SyS_getdents64+0x64/0xcc)
> (SyS_getdents64+0x64/0xcc) from [] (ret_fast_syscall+0x0/0x30)
>
> Howerver, later patches:
> commit 922ec355f86365388203672119b5bca346a45085 ("f2fs crypto: avoid
> unneeded memory allocation when {en/de}crypting symlink")
> commit e06f86e61d7a67fe6e826010f57aa39c674f4b1b ("f2fs crypto: avoid
> unneeded memory allocation in ->readdir")
>
> reverts the codes, which causes panic again in arm, so let's add the old
> patch again.
>
> Signed-off-by: Yunlong Song
> ---
> fs/f2fs/dir.c | 7 +++
> fs/f2fs/namei.c | 10 +-
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> index f00b5ed..c0cf3e7b 100644
> --- a/fs/f2fs/dir.c
> +++ b/fs/f2fs/dir.c
> @@ -825,9 +825,16 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct
> f2fs_dentry_ptr *d,
> int save_len = fstr->len;
> int err;
>
> + de_name.name = kmalloc(de_name.len, GFP_NOFS);
> + if (!de_name.name)
> + return -ENOMEM;
> +
> + memcpy(de_name.name, d->filename[bit_pos], de_name.len);
> +
> err = fscrypt_fname_disk_to_usr(d->inode,
> (u32)de->hash_code, 0,
> _name, fstr);
> + kfree(de_name.name);
> if (err)
> return err;
>
> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> index c4c94c7..2cb70c1 100644
> --- a/fs/f2fs/namei.c
> +++ b/fs/f2fs/namei.c
> @@ -1170,8 +1170,13 @@ static const char *f2fs_encrypted_get_link(struct
> dentry *dentry,
>
> /* Symlink is encrypted */
> sd = (struct fscrypt_symlink_data *)caddr;
> - cstr.name = sd->encrypted_path;
> cstr.len = le16_to_cpu(sd->len);
> + cstr.name = kmalloc(cstr.len, GFP_NOFS);
> + if (!cstr.name) {
> + res = -ENOMEM;
> + goto errout;
> + }
> + memcpy(cstr.name, sd->encrypted_path, cstr.len);
>
> /* this is broken symlink case */
> if (unlikely(cstr.len == 0)) {
> @@ -1198,6 +1203,8 @@ static const char *f2fs_encrypted_get_link(struct
> dentry *dentry,
> goto errout;
> }
>
> + kfree(cstr.name);
> +
> paddr = pstr.name;
>
> /* Null-terminate the name */
> @@ -1207,6 +1214,7 @@ static const char *f2fs_encrypted_get_link(struct
> dentry *dentry,
> set_delayed_call(done, kfree_link, paddr);
> return paddr;
> errout:
> + kfree(cstr.name);
> fscrypt_fname_free_buffer();
> put_page(cpage);
> return ERR_PTR(res);
> --
> 1.8.5.2
>
The pagecache for symlinks in f2fs already uses lowmem only, so the change to
->get_link() isn't needed. Also that part of the patch doesn't apply to
upstream.
For directories we may need your fix. Note: kmalloc + memcpy should be replaced
with kmemdup. But alternatively, directory pages could be restricted to lowmem
which would match ext4.
Eric
Re: [PATCH] f2fs: allocate buffer for decrypting filename to avoid panic
Hi Yunlong,
On Sat, Feb 24, 2018 at 05:14:58PM +0800, Yunlong Song wrote:
> In some platforms (such as arm), high memory is used, then the
> decrypting filename will cause panic, the reason see commit
> 569cf1876a32e574ba8a7fb825cd91bafd003882 ("f2fs crypto: allocate buffer
> for decrypting filename"):
>
> We got dentry pages from high_mem, and its address space directly goes into
> the
> decryption path via f2fs_fname_disk_to_usr.
> But, sg_init_one assumes the address is not from high_mem, so we can get this
> panic since it doesn't call kmap_high but kunmap_high is triggered at the
> end.
>
> kernel BUG at ../../../../../../kernel/mm/highmem.c:290!
> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
> ...
> (kunmap_high+0xb0/0xb8) from [] (__kunmap_atomic+0xa0/0xa4)
> (__kunmap_atomic+0xa0/0xa4) from []
> (blkcipher_walk_done+0x128/0x1ec)
> (blkcipher_walk_done+0x128/0x1ec) from []
> (crypto_cbc_decrypt+0xc0/0x170)
> (crypto_cbc_decrypt+0xc0/0x170) from []
> (crypto_cts_decrypt+0xc0/0x114)
> (crypto_cts_decrypt+0xc0/0x114) from [] (async_decrypt+0x40/0x48)
> (async_decrypt+0x40/0x48) from []
> (f2fs_fname_disk_to_usr+0x124/0x304)
> (f2fs_fname_disk_to_usr+0x124/0x304) from []
> (f2fs_fill_dentries+0xac/0x188)
> (f2fs_fill_dentries+0xac/0x188) from [] (f2fs_readdir+0x1f0/0x300)
> (f2fs_readdir+0x1f0/0x300) from [] (vfs_readdir+0x90/0xb4)
> (vfs_readdir+0x90/0xb4) from [] (SyS_getdents64+0x64/0xcc)
> (SyS_getdents64+0x64/0xcc) from [] (ret_fast_syscall+0x0/0x30)
>
> Howerver, later patches:
> commit 922ec355f86365388203672119b5bca346a45085 ("f2fs crypto: avoid
> unneeded memory allocation when {en/de}crypting symlink")
> commit e06f86e61d7a67fe6e826010f57aa39c674f4b1b ("f2fs crypto: avoid
> unneeded memory allocation in ->readdir")
>
> reverts the codes, which causes panic again in arm, so let's add the old
> patch again.
>
> Signed-off-by: Yunlong Song
> ---
> fs/f2fs/dir.c | 7 +++
> fs/f2fs/namei.c | 10 +-
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> index f00b5ed..c0cf3e7b 100644
> --- a/fs/f2fs/dir.c
> +++ b/fs/f2fs/dir.c
> @@ -825,9 +825,16 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct
> f2fs_dentry_ptr *d,
> int save_len = fstr->len;
> int err;
>
> + de_name.name = kmalloc(de_name.len, GFP_NOFS);
> + if (!de_name.name)
> + return -ENOMEM;
> +
> + memcpy(de_name.name, d->filename[bit_pos], de_name.len);
> +
> err = fscrypt_fname_disk_to_usr(d->inode,
> (u32)de->hash_code, 0,
> _name, fstr);
> + kfree(de_name.name);
> if (err)
> return err;
>
> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> index c4c94c7..2cb70c1 100644
> --- a/fs/f2fs/namei.c
> +++ b/fs/f2fs/namei.c
> @@ -1170,8 +1170,13 @@ static const char *f2fs_encrypted_get_link(struct
> dentry *dentry,
>
> /* Symlink is encrypted */
> sd = (struct fscrypt_symlink_data *)caddr;
> - cstr.name = sd->encrypted_path;
> cstr.len = le16_to_cpu(sd->len);
> + cstr.name = kmalloc(cstr.len, GFP_NOFS);
> + if (!cstr.name) {
> + res = -ENOMEM;
> + goto errout;
> + }
> + memcpy(cstr.name, sd->encrypted_path, cstr.len);
>
> /* this is broken symlink case */
> if (unlikely(cstr.len == 0)) {
> @@ -1198,6 +1203,8 @@ static const char *f2fs_encrypted_get_link(struct
> dentry *dentry,
> goto errout;
> }
>
> + kfree(cstr.name);
> +
> paddr = pstr.name;
>
> /* Null-terminate the name */
> @@ -1207,6 +1214,7 @@ static const char *f2fs_encrypted_get_link(struct
> dentry *dentry,
> set_delayed_call(done, kfree_link, paddr);
> return paddr;
> errout:
> + kfree(cstr.name);
> fscrypt_fname_free_buffer();
> put_page(cpage);
> return ERR_PTR(res);
> --
> 1.8.5.2
>
The pagecache for symlinks in f2fs already uses lowmem only, so the change to
->get_link() isn't needed. Also that part of the patch doesn't apply to
upstream.
For directories we may need your fix. Note: kmalloc + memcpy should be replaced
with kmemdup. But alternatively, directory pages could be restricted to lowmem
which would match ext4.
Eric
[PATCH] f2fs: allocate buffer for decrypting filename to avoid panic
In some platforms (such as arm), high memory is used, then the
decrypting filename will cause panic, the reason see commit
569cf1876a32e574ba8a7fb825cd91bafd003882 ("f2fs crypto: allocate buffer
for decrypting filename"):
We got dentry pages from high_mem, and its address space directly goes into the
decryption path via f2fs_fname_disk_to_usr.
But, sg_init_one assumes the address is not from high_mem, so we can get this
panic since it doesn't call kmap_high but kunmap_high is triggered at the end.
kernel BUG at ../../../../../../kernel/mm/highmem.c:290!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
...
(kunmap_high+0xb0/0xb8) from [] (__kunmap_atomic+0xa0/0xa4)
(__kunmap_atomic+0xa0/0xa4) from []
(blkcipher_walk_done+0x128/0x1ec)
(blkcipher_walk_done+0x128/0x1ec) from []
(crypto_cbc_decrypt+0xc0/0x170)
(crypto_cbc_decrypt+0xc0/0x170) from []
(crypto_cts_decrypt+0xc0/0x114)
(crypto_cts_decrypt+0xc0/0x114) from [] (async_decrypt+0x40/0x48)
(async_decrypt+0x40/0x48) from []
(f2fs_fname_disk_to_usr+0x124/0x304)
(f2fs_fname_disk_to_usr+0x124/0x304) from []
(f2fs_fill_dentries+0xac/0x188)
(f2fs_fill_dentries+0xac/0x188) from [] (f2fs_readdir+0x1f0/0x300)
(f2fs_readdir+0x1f0/0x300) from [] (vfs_readdir+0x90/0xb4)
(vfs_readdir+0x90/0xb4) from [] (SyS_getdents64+0x64/0xcc)
(SyS_getdents64+0x64/0xcc) from [] (ret_fast_syscall+0x0/0x30)
Howerver, later patches:
commit 922ec355f86365388203672119b5bca346a45085 ("f2fs crypto: avoid
unneeded memory allocation when {en/de}crypting symlink")
commit e06f86e61d7a67fe6e826010f57aa39c674f4b1b ("f2fs crypto: avoid
unneeded memory allocation in ->readdir")
reverts the codes, which causes panic again in arm, so let's add the old
patch again.
Signed-off-by: Yunlong Song
---
fs/f2fs/dir.c | 7 +++
fs/f2fs/namei.c | 10 +-
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index f00b5ed..c0cf3e7b 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -825,9 +825,16 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct
f2fs_dentry_ptr *d,
int save_len = fstr->len;
int err;
+ de_name.name = kmalloc(de_name.len, GFP_NOFS);
+ if (!de_name.name)
+ return -ENOMEM;
+
+ memcpy(de_name.name, d->filename[bit_pos], de_name.len);
+
err = fscrypt_fname_disk_to_usr(d->inode,
(u32)de->hash_code, 0,
_name, fstr);
+ kfree(de_name.name);
if (err)
return err;
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index c4c94c7..2cb70c1 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -1170,8 +1170,13 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
/* Symlink is encrypted */
sd = (struct fscrypt_symlink_data *)caddr;
- cstr.name = sd->encrypted_path;
cstr.len = le16_to_cpu(sd->len);
+ cstr.name = kmalloc(cstr.len, GFP_NOFS);
+ if (!cstr.name) {
+ res = -ENOMEM;
+ goto errout;
+ }
+ memcpy(cstr.name, sd->encrypted_path, cstr.len);
/* this is broken symlink case */
if (unlikely(cstr.len == 0)) {
@@ -1198,6 +1203,8 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
goto errout;
}
+ kfree(cstr.name);
+
paddr = pstr.name;
/* Null-terminate the name */
@@ -1207,6 +1214,7 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
set_delayed_call(done, kfree_link, paddr);
return paddr;
errout:
+ kfree(cstr.name);
fscrypt_fname_free_buffer();
put_page(cpage);
return ERR_PTR(res);
--
1.8.5.2
[PATCH] f2fs: allocate buffer for decrypting filename to avoid panic
In some platforms (such as arm), high memory is used, then the
decrypting filename will cause panic, the reason see commit
569cf1876a32e574ba8a7fb825cd91bafd003882 ("f2fs crypto: allocate buffer
for decrypting filename"):
We got dentry pages from high_mem, and its address space directly goes into the
decryption path via f2fs_fname_disk_to_usr.
But, sg_init_one assumes the address is not from high_mem, so we can get this
panic since it doesn't call kmap_high but kunmap_high is triggered at the end.
kernel BUG at ../../../../../../kernel/mm/highmem.c:290!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
...
(kunmap_high+0xb0/0xb8) from [] (__kunmap_atomic+0xa0/0xa4)
(__kunmap_atomic+0xa0/0xa4) from []
(blkcipher_walk_done+0x128/0x1ec)
(blkcipher_walk_done+0x128/0x1ec) from []
(crypto_cbc_decrypt+0xc0/0x170)
(crypto_cbc_decrypt+0xc0/0x170) from []
(crypto_cts_decrypt+0xc0/0x114)
(crypto_cts_decrypt+0xc0/0x114) from [] (async_decrypt+0x40/0x48)
(async_decrypt+0x40/0x48) from []
(f2fs_fname_disk_to_usr+0x124/0x304)
(f2fs_fname_disk_to_usr+0x124/0x304) from []
(f2fs_fill_dentries+0xac/0x188)
(f2fs_fill_dentries+0xac/0x188) from [] (f2fs_readdir+0x1f0/0x300)
(f2fs_readdir+0x1f0/0x300) from [] (vfs_readdir+0x90/0xb4)
(vfs_readdir+0x90/0xb4) from [] (SyS_getdents64+0x64/0xcc)
(SyS_getdents64+0x64/0xcc) from [] (ret_fast_syscall+0x0/0x30)
Howerver, later patches:
commit 922ec355f86365388203672119b5bca346a45085 ("f2fs crypto: avoid
unneeded memory allocation when {en/de}crypting symlink")
commit e06f86e61d7a67fe6e826010f57aa39c674f4b1b ("f2fs crypto: avoid
unneeded memory allocation in ->readdir")
reverts the codes, which causes panic again in arm, so let's add the old
patch again.
Signed-off-by: Yunlong Song
---
fs/f2fs/dir.c | 7 +++
fs/f2fs/namei.c | 10 +-
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index f00b5ed..c0cf3e7b 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -825,9 +825,16 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct
f2fs_dentry_ptr *d,
int save_len = fstr->len;
int err;
+ de_name.name = kmalloc(de_name.len, GFP_NOFS);
+ if (!de_name.name)
+ return -ENOMEM;
+
+ memcpy(de_name.name, d->filename[bit_pos], de_name.len);
+
err = fscrypt_fname_disk_to_usr(d->inode,
(u32)de->hash_code, 0,
_name, fstr);
+ kfree(de_name.name);
if (err)
return err;
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index c4c94c7..2cb70c1 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -1170,8 +1170,13 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
/* Symlink is encrypted */
sd = (struct fscrypt_symlink_data *)caddr;
- cstr.name = sd->encrypted_path;
cstr.len = le16_to_cpu(sd->len);
+ cstr.name = kmalloc(cstr.len, GFP_NOFS);
+ if (!cstr.name) {
+ res = -ENOMEM;
+ goto errout;
+ }
+ memcpy(cstr.name, sd->encrypted_path, cstr.len);
/* this is broken symlink case */
if (unlikely(cstr.len == 0)) {
@@ -1198,6 +1203,8 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
goto errout;
}
+ kfree(cstr.name);
+
paddr = pstr.name;
/* Null-terminate the name */
@@ -1207,6 +1214,7 @@ static const char *f2fs_encrypted_get_link(struct dentry
*dentry,
set_delayed_call(done, kfree_link, paddr);
return paddr;
errout:
+ kfree(cstr.name);
fscrypt_fname_free_buffer();
put_page(cpage);
return ERR_PTR(res);
--
1.8.5.2
