Messages in this thread | | | From | shankarapailoor <> | Date | Mon, 4 Jun 2018 21:53:53 -0700 | Subject | general protection fault in sockfs_setattr |
| |
Hi,
I have been fuzzing Linux 4.17-rc7 with Syzkaller and found the following crash: https://pastebin.com/ixX3RB9j
Syzkaller isolated the cause of the bug to the following program:
socketpair$unix(0x1, 0x1, 0x0, &(0x7f0000000000)={<r0=>0xffffffffffffffff, <r1=>0xffffffffffffffff}) getresuid(&(0x7f0000000080)=<r2=>0x0, &(0x7f00000000c0), &(0x7f0000000700))r3 = getegid() fchownat(r0, &(0x7f0000000040)='\x00', r2, r3, 0x1000) dup3(r1, r0, 0x80000)
The problematic area appears to be here:
static int sockfs_setattr(struct dentry *dentry, struct iattr *iattr) { int err = simple_setattr(dentry, iattr);
if (!err && (iattr->ia_valid & ATTR_UID)) { struct socket *sock = SOCKET_I(d_inode(dentry));
sock->sk->sk_uid = iattr->ia_uid; //KASAN GPF } return err; }
If dup3 is called concurrently with fchownat then can sock->sk be NULL?
-- Regards, Shankara Pailoor
| |