| Message ID | 20221206015806.3420321-2-yebin@huaweicloud.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Fix two issue about ext4 extended attribute | expand |
On Tue 06-12-22 09:58:01, Ye Bin wrote: > From: Ye Bin <yebin10@huawei.com> > > Syzbot found the following issue: > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 3631 at mm/page_alloc.c:5534 __alloc_pages+0x30a/0x560 mm/page_alloc.c:5534 > Modules linked in: > CPU: 1 PID: 3631 Comm: syz-executor261 Not tainted 6.1.0-rc6-syzkaller-00308-g644e9524388a #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 > RIP: 0010:__alloc_pages+0x30a/0x560 mm/page_alloc.c:5534 > RSP: 0018:ffffc90003ccf080 EFLAGS: 00010246 > RAX: ffffc90003ccf0e0 RBX: 000000000000000c RCX: 0000000000000000 > RDX: 0000000000000028 RSI: 0000000000000000 RDI: ffffc90003ccf108 > RBP: ffffc90003ccf198 R08: dffffc0000000000 R09: ffffc90003ccf0e0 > R10: fffff52000799e21 R11: 1ffff92000799e1c R12: 0000000000040c40 > R13: 1ffff92000799e18 R14: dffffc0000000000 R15: 1ffff92000799e14 > FS: 0000555555c10300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007ffc36f70000 CR3: 00000000744ad000 CR4: 00000000003506e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > __alloc_pages_node include/linux/gfp.h:223 [inline] > alloc_pages_node include/linux/gfp.h:246 [inline] > __kmalloc_large_node+0x8a/0x1a0 mm/slab_common.c:1096 > __do_kmalloc_node mm/slab_common.c:943 [inline] > __kmalloc+0xfe/0x1a0 mm/slab_common.c:968 > kmalloc include/linux/slab.h:558 [inline] > ext4_xattr_move_to_block fs/ext4/xattr.c:2558 [inline] > ext4_xattr_make_inode_space fs/ext4/xattr.c:2673 [inline] > ext4_expand_extra_isize_ea+0xe3f/0x1cd0 fs/ext4/xattr.c:2765 > __ext4_expand_extra_isize+0x2b8/0x3f0 fs/ext4/inode.c:5857 > ext4_try_to_expand_extra_isize fs/ext4/inode.c:5900 [inline] > __ext4_mark_inode_dirty+0x51a/0x670 fs/ext4/inode.c:5978 > ext4_inline_data_truncate+0x548/0xd00 fs/ext4/inline.c:2021 > ext4_truncate+0x341/0xeb0 fs/ext4/inode.c:4221 > ext4_process_orphan+0x1aa/0x2d0 fs/ext4/orphan.c:339 > ext4_orphan_cleanup+0xb60/0x1340 fs/ext4/orphan.c:474 > __ext4_fill_super fs/ext4/super.c:5515 [inline] > ext4_fill_super+0x80ed/0x8610 fs/ext4/super.c:5643 > get_tree_bdev+0x400/0x620 fs/super.c:1324 > vfs_get_tree+0x88/0x270 fs/super.c:1531 > do_new_mount+0x289/0xad0 fs/namespace.c:3040 > do_mount fs/namespace.c:3383 [inline] > __do_sys_mount fs/namespace.c:3591 [inline] > __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > </TASK> > > Reason is allocate 16M memory by kmalloc, but MAX_ORDER is 11, kmalloc > can allocate maxium size memory is 4M. > XATTR_SIZE_MAX is currently 64k, but EXT4_XATTR_SIZE_MAX is '(1 << 24)', > so 'ext4_xattr_check_entries()' regards this length as legal. Then trigger > warning in 'ext4_xattr_move_to_block()'. > To solve above issue, according to Jan Kara's suggestion use kvmalloc() > to allocate memory in ext4_xattr_move_to_block(). > > Reported-by: syzbot+4d99a966fd74bdeeec36@syzkaller.appspotmail.com > Fixes: 54dd0e0a1b25 ("ext4: add extra checks to ext4_xattr_block_get()") > Signed-off-by: Ye Bin <yebin10@huawei.com> The changelog speak about kvmalloc() while your patch changes EXT4_XATTR_SIZE_MAX. This needs to be fixed. If Ted is find with this change, I have no problem with it either but I remember there were some discussions about what EXT4_XATTR_SIZE_MAX should be when ea_inode feature has been developed. Ted might remember. Also the change from kmalloc() to kvmalloc() is a desirable one anyway. It is not always easy to find physically contiguous 64k of memory so kvmalloc() makes the allocation much more likely to succeed. Honza
On 2022/12/6 20:04, Jan Kara wrote: > On Tue 06-12-22 09:58:01, Ye Bin wrote: >> From: Ye Bin <yebin10@huawei.com> >> >> Syzbot found the following issue: >> ------------[ cut here ]------------ >> WARNING: CPU: 1 PID: 3631 at mm/page_alloc.c:5534 __alloc_pages+0x30a/0x560 mm/page_alloc.c:5534 >> Modules linked in: >> CPU: 1 PID: 3631 Comm: syz-executor261 Not tainted 6.1.0-rc6-syzkaller-00308-g644e9524388a #0 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 >> RIP: 0010:__alloc_pages+0x30a/0x560 mm/page_alloc.c:5534 >> RSP: 0018:ffffc90003ccf080 EFLAGS: 00010246 >> RAX: ffffc90003ccf0e0 RBX: 000000000000000c RCX: 0000000000000000 >> RDX: 0000000000000028 RSI: 0000000000000000 RDI: ffffc90003ccf108 >> RBP: ffffc90003ccf198 R08: dffffc0000000000 R09: ffffc90003ccf0e0 >> R10: fffff52000799e21 R11: 1ffff92000799e1c R12: 0000000000040c40 >> R13: 1ffff92000799e18 R14: dffffc0000000000 R15: 1ffff92000799e14 >> FS: 0000555555c10300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00007ffc36f70000 CR3: 00000000744ad000 CR4: 00000000003506e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> Call Trace: >> <TASK> >> __alloc_pages_node include/linux/gfp.h:223 [inline] >> alloc_pages_node include/linux/gfp.h:246 [inline] >> __kmalloc_large_node+0x8a/0x1a0 mm/slab_common.c:1096 >> __do_kmalloc_node mm/slab_common.c:943 [inline] >> __kmalloc+0xfe/0x1a0 mm/slab_common.c:968 >> kmalloc include/linux/slab.h:558 [inline] >> ext4_xattr_move_to_block fs/ext4/xattr.c:2558 [inline] >> ext4_xattr_make_inode_space fs/ext4/xattr.c:2673 [inline] >> ext4_expand_extra_isize_ea+0xe3f/0x1cd0 fs/ext4/xattr.c:2765 >> __ext4_expand_extra_isize+0x2b8/0x3f0 fs/ext4/inode.c:5857 >> ext4_try_to_expand_extra_isize fs/ext4/inode.c:5900 [inline] >> __ext4_mark_inode_dirty+0x51a/0x670 fs/ext4/inode.c:5978 >> ext4_inline_data_truncate+0x548/0xd00 fs/ext4/inline.c:2021 >> ext4_truncate+0x341/0xeb0 fs/ext4/inode.c:4221 >> ext4_process_orphan+0x1aa/0x2d0 fs/ext4/orphan.c:339 >> ext4_orphan_cleanup+0xb60/0x1340 fs/ext4/orphan.c:474 >> __ext4_fill_super fs/ext4/super.c:5515 [inline] >> ext4_fill_super+0x80ed/0x8610 fs/ext4/super.c:5643 >> get_tree_bdev+0x400/0x620 fs/super.c:1324 >> vfs_get_tree+0x88/0x270 fs/super.c:1531 >> do_new_mount+0x289/0xad0 fs/namespace.c:3040 >> do_mount fs/namespace.c:3383 [inline] >> __do_sys_mount fs/namespace.c:3591 [inline] >> __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568 >> do_syscall_x64 arch/x86/entry/common.c:50 [inline] >> do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 >> entry_SYSCALL_64_after_hwframe+0x63/0xcd >> </TASK> >> >> Reason is allocate 16M memory by kmalloc, but MAX_ORDER is 11, kmalloc >> can allocate maxium size memory is 4M. >> XATTR_SIZE_MAX is currently 64k, but EXT4_XATTR_SIZE_MAX is '(1 << 24)', >> so 'ext4_xattr_check_entries()' regards this length as legal. Then trigger >> warning in 'ext4_xattr_move_to_block()'. >> To solve above issue, according to Jan Kara's suggestion use kvmalloc() >> to allocate memory in ext4_xattr_move_to_block(). >> >> Reported-by: syzbot+4d99a966fd74bdeeec36@syzkaller.appspotmail.com >> Fixes: 54dd0e0a1b25 ("ext4: add extra checks to ext4_xattr_block_get()") >> Signed-off-by: Ye Bin <yebin10@huawei.com> > The changelog speak about kvmalloc() while your patch changes > EXT4_XATTR_SIZE_MAX. This needs to be fixed. If Ted is find with this > change, I have no problem with it either but I remember there were some > discussions about what EXT4_XATTR_SIZE_MAX should be when ea_inode feature > has been developed. Ted might remember. I'm sorry I forgot to modify the commit message, I will modify the changelog again. > Also the change from kmalloc() to kvmalloc() is a desirable one anyway. It > is not always easy to find physically contiguous 64k of memory so > kvmalloc() makes the allocation much more likely to succeed. > > Honza A later patch use kvmalloc to allocate extended attribute value memory.
diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h index 824faf0b15a8..444ee46838c3 100644 --- a/fs/ext4/xattr.h +++ b/fs/ext4/xattr.h @@ -71,15 +71,10 @@ struct ext4_xattr_entry { #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1)) /* - * XATTR_SIZE_MAX is currently 64k, but for the purposes of checking - * for file system consistency errors, we use a somewhat bigger value. - * This allows XATTR_SIZE_MAX to grow in the future, but by using this - * instead of INT_MAX for certain consistency checks, we don't need to - * worry about arithmetic overflows. (Actually XATTR_SIZE_MAX is - * defined in include/uapi/linux/limits.h, so changing it is going - * not going to be trivial....) + * Use XATTR_SIZE_MAX to checking for file system consistency errors. Extended + * attribute length exceed XATTR_SIZE_MAX is ilegal. */ -#define EXT4_XATTR_SIZE_MAX (1 << 24) +#define EXT4_XATTR_SIZE_MAX XATTR_SIZE_MAX /* * The minimum size of EA value when you start storing it in an external inode