From: Chao Yu <[email protected]>
commit c6ad7fd16657ebd34a87a97d9588195aae87597d upstream.
As Wenqing Liu reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=216456
BUG: KASAN: use-after-free in recover_data+0x63ae/0x6ae0 [f2fs]
Read of size 4 at addr ffff8881464dcd80 by task mount/1013
CPU: 3 PID: 1013 Comm: mount Tainted: G W 6.0.0-rc4 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
Call Trace:
dump_stack_lvl+0x45/0x5e
print_report.cold+0xf3/0x68d
kasan_report+0xa8/0x130
recover_data+0x63ae/0x6ae0 [f2fs]
f2fs_recover_fsync_data+0x120d/0x1fc0 [f2fs]
f2fs_fill_super+0x4665/0x61e0 [f2fs]
mount_bdev+0x2cf/0x3b0
legacy_get_tree+0xed/0x1d0
vfs_get_tree+0x81/0x2b0
path_mount+0x47e/0x19d0
do_mount+0xce/0xf0
__x64_sys_mount+0x12c/0x1a0
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
The root cause is: in fuzzed image, SSA table is corrupted: ofs_in_node
is larger than ADDRS_PER_PAGE(), result in out-of-range access on 4k-size
page.
- recover_data
- do_recover_data
- check_index_in_prev_nodes
- f2fs_data_blkaddr
This patch adds sanity check on summary info in recovery and GC flow
in where the flows rely on them.
After patch:
[ 29.310883] F2FS-fs (loop0): Inconsistent ofs_in_node:65286 in summary, ino:0, nid:6, max:1018
Cc: [email protected]
Reported-by: Wenqing Liu <[email protected]>
Signed-off-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/f2fs/gc.c | 10 +++++++++-
fs/f2fs/recovery.c | 15 ++++++++++++---
2 files changed, 21 insertions(+), 4 deletions(-)
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -977,7 +977,7 @@ static bool is_alive(struct f2fs_sb_info
{
struct page *node_page;
nid_t nid;
- unsigned int ofs_in_node;
+ unsigned int ofs_in_node, max_addrs;
block_t source_blkaddr;
nid = le32_to_cpu(sum->nid);
@@ -1003,6 +1003,14 @@ static bool is_alive(struct f2fs_sb_info
return false;
}
+ max_addrs = IS_INODE(node_page) ? DEF_ADDRS_PER_INODE :
+ DEF_ADDRS_PER_BLOCK;
+ if (ofs_in_node >= max_addrs) {
+ f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u",
+ ofs_in_node, dni->ino, dni->nid, max_addrs);
+ return false;
+ }
+
*nofs = ofs_of_node(node_page);
source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
f2fs_put_page(node_page, 1);
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -437,7 +437,7 @@ static int check_index_in_prev_nodes(str
struct dnode_of_data tdn = *dn;
nid_t ino, nid;
struct inode *inode;
- unsigned int offset;
+ unsigned int offset, ofs_in_node, max_addrs;
block_t bidx;
int i;
@@ -463,15 +463,24 @@ static int check_index_in_prev_nodes(str
got_it:
/* Use the locked dnode page and inode */
nid = le32_to_cpu(sum.nid);
+ ofs_in_node = le16_to_cpu(sum.ofs_in_node);
+
+ max_addrs = ADDRS_PER_PAGE(dn->node_page, dn->inode);
+ if (ofs_in_node >= max_addrs) {
+ f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%lu, nid:%u, max:%u",
+ ofs_in_node, dn->inode->i_ino, nid, max_addrs);
+ return -EFSCORRUPTED;
+ }
+
if (dn->inode->i_ino == nid) {
tdn.nid = nid;
if (!dn->inode_page_locked)
lock_page(dn->inode_page);
tdn.node_page = dn->inode_page;
- tdn.ofs_in_node = le16_to_cpu(sum.ofs_in_node);
+ tdn.ofs_in_node = ofs_in_node;
goto truncate_out;
} else if (dn->nid == nid) {
- tdn.ofs_in_node = le16_to_cpu(sum.ofs_in_node);
+ tdn.ofs_in_node = ofs_in_node;
goto truncate_out;
}
Hi!
> From: Chao Yu <[email protected]>
>
> commit c6ad7fd16657ebd34a87a97d9588195aae87597d upstream.
>
> As Wenqing Liu reported in bugzilla:
>
> https://bugzilla.kernel.org/show_bug.cgi?id=216456
>
> BUG: KASAN: use-after-free in recover_data+0x63ae/0x6ae0 [f2fs]
> Read of size 4 at addr ffff8881464dcd80 by task mount/1013
I believe this is missing put_page on the error path:
> +++ b/fs/f2fs/gc.c
> @@ -1003,6 +1003,14 @@ static bool is_alive(struct f2fs_sb_info
> return false;
> }
>
> + max_addrs = IS_INODE(node_page) ? DEF_ADDRS_PER_INODE :
> + DEF_ADDRS_PER_BLOCK;
> + if (ofs_in_node >= max_addrs) {
> + f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u",
> + ofs_in_node, dni->ino, dni->nid, max_addrs);
> + return false;
> + }
> +
> *nofs = ofs_of_node(node_page);
> source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
> f2fs_put_page(node_page, 1);
So something like this is needed. (Feel free to test/adapt/apply).
Signed-off-by: Pavel Machek <[email protected]>
Best regards,
Pavel
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 4546e01b2ee0..dab794225cce 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1110,6 +1110,7 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
if (ofs_in_node >= max_addrs) {
f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u",
ofs_in_node, dni->ino, dni->nid, max_addrs);
+ f2fs_put_page(node_page, 1);
return false;
}
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
On 10/24, Pavel Machek wrote:
> Hi!
>
> > From: Chao Yu <[email protected]>
> >
> > commit c6ad7fd16657ebd34a87a97d9588195aae87597d upstream.
> >
> > As Wenqing Liu reported in bugzilla:
> >
> > https://bugzilla.kernel.org/show_bug.cgi?id=216456
> >
> > BUG: KASAN: use-after-free in recover_data+0x63ae/0x6ae0 [f2fs]
> > Read of size 4 at addr ffff8881464dcd80 by task mount/1013
>
> I believe this is missing put_page on the error path:
>
> > +++ b/fs/f2fs/gc.c
> > @@ -1003,6 +1003,14 @@ static bool is_alive(struct f2fs_sb_info
> > return false;
> > }
> >
> > + max_addrs = IS_INODE(node_page) ? DEF_ADDRS_PER_INODE :
> > + DEF_ADDRS_PER_BLOCK;
> > + if (ofs_in_node >= max_addrs) {
> > + f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u",
> > + ofs_in_node, dni->ino, dni->nid, max_addrs);
> > + return false;
> > + }
> > +
> > *nofs = ofs_of_node(node_page);
> > source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
> > f2fs_put_page(node_page, 1);
>
> So something like this is needed. (Feel free to test/adapt/apply).
Urg.. thank you so much for pointing this out. Applied the change to the tree.
https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=dev&id=a22aeafb3d3569aecf811dca1aceff656695cdb4
>
> Signed-off-by: Pavel Machek <[email protected]>
>
> Best regards,
> Pavel
>
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 4546e01b2ee0..dab794225cce 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -1110,6 +1110,7 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
> if (ofs_in_node >= max_addrs) {
> f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u",
> ofs_in_node, dni->ino, dni->nid, max_addrs);
> + f2fs_put_page(node_page, 1);
> return false;
> }
>
>
> --
> DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
On 2022/10/25 1:30, Pavel Machek wrote:
> Hi!
>
>> From: Chao Yu <[email protected]>
>>
>> commit c6ad7fd16657ebd34a87a97d9588195aae87597d upstream.
>>
>> As Wenqing Liu reported in bugzilla:
>>
>> https://bugzilla.kernel.org/show_bug.cgi?id=216456
>>
>> BUG: KASAN: use-after-free in recover_data+0x63ae/0x6ae0 [f2fs]
>> Read of size 4 at addr ffff8881464dcd80 by task mount/1013
>
> I believe this is missing put_page on the error path:
>
>> +++ b/fs/f2fs/gc.c
>> @@ -1003,6 +1003,14 @@ static bool is_alive(struct f2fs_sb_info
>> return false;
>> }
>>
>> + max_addrs = IS_INODE(node_page) ? DEF_ADDRS_PER_INODE :
>> + DEF_ADDRS_PER_BLOCK;
>> + if (ofs_in_node >= max_addrs) {
>> + f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u",
>> + ofs_in_node, dni->ino, dni->nid, max_addrs);
>> + return false;
>> + }
>> +
>> *nofs = ofs_of_node(node_page);
>> source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
>> f2fs_put_page(node_page, 1);
>
> So something like this is needed. (Feel free to test/adapt/apply).
>
> Signed-off-by: Pavel Machek <[email protected]>
>
> Best regards,
> Pavel
>
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 4546e01b2ee0..dab794225cce 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -1110,6 +1110,7 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
> if (ofs_in_node >= max_addrs) {
> f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u",
> ofs_in_node, dni->ino, dni->nid, max_addrs);
> + f2fs_put_page(node_page, 1);
> return false;
> }
My bad, thanks for fixing this.
Reviewed-by: Chao Yu <[email protected]>
Thanks,
>
>