5.10-stable review patch. If anyone has any objections, please let me know.
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From: Paulo Alcantara pc@manguebit.com
[ Upstream commit 3a42709fa909e22b0be4bb1e2795aa04ada732a3 ]
Validate @ioctl_rsp->OutputOffset and @ioctl_rsp->OutputCount so that their sum does not wrap to a number that is smaller than @reparse_buf and we end up with a wild pointer as follows:
BUG: unable to handle page fault for address: ffff88809c5cd45f #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 4a01067 P4D 4a01067 PUD 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 2 PID: 1260 Comm: mount.cifs Not tainted 6.7.0-rc4 #2 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 RIP: 0010:smb2_query_reparse_point+0x3e0/0x4c0 [cifs] Code: ff ff e8 f3 51 fe ff 41 89 c6 58 5a 45 85 f6 0f 85 14 fe ff ff 49 8b 57 48 8b 42 60 44 8b 42 64 42 8d 0c 00 49 39 4f 50 72 40 <8b> 04 02 48 8b 9d f0 fe ff ff 49 8b 57 50 89 03 48 8b 9d e8 fe ff RSP: 0018:ffffc90000347a90 EFLAGS: 00010212 RAX: 000000008000001f RBX: ffff88800ae11000 RCX: 00000000000000ec RDX: ffff88801c5cd440 RSI: 0000000000000000 RDI: ffffffff82004aa4 RBP: ffffc90000347bb0 R08: 00000000800000cd R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000024 R12: ffff8880114d4100 R13: ffff8880114d4198 R14: 0000000000000000 R15: ffff8880114d4000 FS: 00007f02c07babc0(0000) GS:ffff88806ba00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88809c5cd45f CR3: 0000000011750000 CR4: 0000000000750ef0 PKRU: 55555554 Call Trace: <TASK> ? __die+0x23/0x70 ? page_fault_oops+0x181/0x480 ? search_module_extables+0x19/0x60 ? srso_alias_return_thunk+0x5/0xfbef5 ? exc_page_fault+0x1b6/0x1c0 ? asm_exc_page_fault+0x26/0x30 ? _raw_spin_unlock_irqrestore+0x44/0x60 ? smb2_query_reparse_point+0x3e0/0x4c0 [cifs] cifs_get_fattr+0x16e/0xa50 [cifs] ? srso_alias_return_thunk+0x5/0xfbef5 ? lock_acquire+0xbf/0x2b0 cifs_root_iget+0x163/0x5f0 [cifs] cifs_smb3_do_mount+0x5bd/0x780 [cifs] smb3_get_tree+0xd9/0x290 [cifs] vfs_get_tree+0x2c/0x100 ? capable+0x37/0x70 path_mount+0x2d7/0xb80 ? srso_alias_return_thunk+0x5/0xfbef5 ? _raw_spin_unlock_irqrestore+0x44/0x60 __x64_sys_mount+0x11a/0x150 do_syscall_64+0x47/0xf0 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7f02c08d5b1e
Fixes: 2e4564b31b64 ("smb3: add support for stat of WSL reparse points for special file types") Cc: stable@vger.kernel.org Reported-by: Robert Morris rtm@csail.mit.edu Signed-off-by: Paulo Alcantara (SUSE) pc@manguebit.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/cifs/smb2ops.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index e58525a958270..26edaeb4245d8 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -3099,7 +3099,7 @@ smb2_query_reparse_tag(const unsigned int xid, struct cifs_tcon *tcon, struct kvec close_iov[1]; struct smb2_ioctl_rsp *ioctl_rsp; struct reparse_data_buffer *reparse_buf; - u32 plen; + u32 off, count, len;
cifs_dbg(FYI, "%s: path: %s\n", __func__, full_path);
@@ -3178,16 +3178,22 @@ smb2_query_reparse_tag(const unsigned int xid, struct cifs_tcon *tcon, */ if (rc == 0) { /* See MS-FSCC 2.3.23 */ + off = le32_to_cpu(ioctl_rsp->OutputOffset); + count = le32_to_cpu(ioctl_rsp->OutputCount); + if (check_add_overflow(off, count, &len) || + len > rsp_iov[1].iov_len) { + cifs_tcon_dbg(VFS, "%s: invalid ioctl: off=%d count=%d\n", + __func__, off, count); + rc = -EIO; + goto query_rp_exit; + }
- reparse_buf = (struct reparse_data_buffer *) - ((char *)ioctl_rsp + - le32_to_cpu(ioctl_rsp->OutputOffset)); - plen = le32_to_cpu(ioctl_rsp->OutputCount); - - if (plen + le32_to_cpu(ioctl_rsp->OutputOffset) > - rsp_iov[1].iov_len) { - cifs_tcon_dbg(FYI, "srv returned invalid ioctl len: %d\n", - plen); + reparse_buf = (void *)((u8 *)ioctl_rsp + off); + len = sizeof(*reparse_buf); + if (count < len || + count < le16_to_cpu(reparse_buf->ReparseDataLength) + len) { + cifs_tcon_dbg(VFS, "%s: invalid ioctl: off=%d count=%d\n", + __func__, off, count); rc = -EIO; goto query_rp_exit; }