CVE-2022-49352

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ext4: fix warning in ext4_handle_inode_extension<br /> <br /> We got issue as follows:<br /> EXT4-fs error (device loop0) in ext4_reserve_inode_write:5741: Out of memory<br /> EXT4-fs error (device loop0): ext4_setattr:5462: inode #13: comm syz-executor.0: mark_inode_dirty error<br /> EXT4-fs error (device loop0) in ext4_setattr:5519: Out of memory<br /> EXT4-fs error (device loop0): ext4_ind_map_blocks:595: inode #13: comm syz-executor.0: Can&amp;#39;t allocate blocks for non-extent mapped inodes with bigalloc<br /> ------------[ cut here ]------------<br /> WARNING: CPU: 1 PID: 4361 at fs/ext4/file.c:301 ext4_file_write_iter+0x11c9/0x1220<br /> Modules linked in:<br /> CPU: 1 PID: 4361 Comm: syz-executor.0 Not tainted 5.10.0+ #1<br /> RIP: 0010:ext4_file_write_iter+0x11c9/0x1220<br /> RSP: 0018:ffff924d80b27c00 EFLAGS: 00010282<br /> RAX: ffffffff815a3379 RBX: 0000000000000000 RCX: 000000003b000000<br /> RDX: ffff924d81601000 RSI: 00000000000009cc RDI: 00000000000009cd<br /> RBP: 000000000000000d R08: ffffffffbc5a2c6b R09: 0000902e0e52a96f<br /> R10: ffff902e2b7c1b40 R11: ffff902e2b7c1b40 R12: 000000000000000a<br /> R13: 0000000000000001 R14: ffff902e0e52aa10 R15: ffffffffffffff8b<br /> FS: 00007f81a7f65700(0000) GS:ffff902e3bc80000(0000) knlGS:0000000000000000<br /> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033<br /> CR2: ffffffffff600400 CR3: 000000012db88001 CR4: 00000000003706e0<br /> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000<br /> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400<br /> Call Trace:<br /> do_iter_readv_writev+0x2e5/0x360<br /> do_iter_write+0x112/0x4c0<br /> do_pwritev+0x1e5/0x390<br /> __x64_sys_pwritev2+0x7e/0xa0<br /> do_syscall_64+0x37/0x50<br /> entry_SYSCALL_64_after_hwframe+0x44/0xa9<br /> <br /> Above issue may happen as follows:<br /> Assume<br /> inode.i_size=4096<br /> EXT4_I(inode)-&gt;i_disksize=4096<br /> <br /> step 1: set inode-&gt;i_isize = 8192<br /> ext4_setattr<br /> if (attr-&gt;ia_size != inode-&gt;i_size)<br /> EXT4_I(inode)-&gt;i_disksize = attr-&gt;ia_size;<br /> rc = ext4_mark_inode_dirty<br /> ext4_reserve_inode_write<br /> ext4_get_inode_loc<br /> __ext4_get_inode_loc<br /> sb_getblk --&gt; return -ENOMEM<br /> ...<br /> if (!error) -&gt;will not update i_size<br /> i_size_write(inode, attr-&gt;ia_size);<br /> Now:<br /> inode.i_size=4096<br /> EXT4_I(inode)-&gt;i_disksize=8192<br /> <br /> step 2: Direct write 4096 bytes<br /> ext4_file_write_iter<br /> ext4_dio_write_iter<br /> iomap_dio_rw -&gt;return error<br /> if (extend)<br /> ext4_handle_inode_extension<br /> WARN_ON_ONCE(i_size_read(inode) i_disksize);<br /> -&gt;Then trigger warning.<br /> <br /> To solve above issue, if mark inode dirty failed in ext4_setattr just<br /> set &amp;#39;EXT4_I(inode)-&gt;i_disksize&amp;#39; with old value.