libceph: Avoid using invalid osd indices from primary_temp

Overview

In the Linux kernel, the following vulnerability has been resolved:

libceph: Avoid using invalid osd indices from primary_temp

A corrupted osdmap received from a Ceph monitor or OSD may contain osd indices in its pg_temp, primary_temp, pg_upmap, and pg_upmap_items parts that don't exist, i.e., that are greater than max_osd or smaller than CEPH_HOMELESS_OSD (-1). These indices are used to create the up and acting set in ceph_pg_to_up_acting_osds(), called from calc_target(). While most of these osd indices are checked, the one from primary_temp is not. Subsequently, this may lead to calc_target() returning this (potentially invalid) index as target osd for a (linger) request. Because the osd_state, osd_weight, and osd_addr arrays only contain max_osd entries (with indices 0 to max_osd -1), this leads to out-of-bounds accesses when trying to read values from these arrays.

This patch fixes the issue by adding a check to get_temp_osds(), so that only valid osd indices from primary_temp are used, and it falls back to using the primary from pg_temp or the up set if it is invalid.

[ idryomov: changelog ]

Affected

• Linux >= 5e8d4d36bf23bb7baf027c479d54395840219928 < 505fc50b8ff8e687b7e3ef6866269dea27366224
• Linux >= 5e8d4d36bf23bb7baf027c479d54395840219928 < 1c705fe8e59c6b16f48964973fb23c8ec4735b73
• Linux >= 5e8d4d36bf23bb7baf027c479d54395840219928 < dfe1877d351b99eb1b1a62a3fc2d174220e88e20
• Linux >= 5e8d4d36bf23bb7baf027c479d54395840219928 < e2ffeec85201b2bb748e99e12539ee1b92f62796
• Linux >= 5e8d4d36bf23bb7baf027c479d54395840219928 < 6799d4a916ffcb3d450d8440f9fe0f0862f768d6
• Linux >= 5e8d4d36bf23bb7baf027c479d54395840219928 < 4f392fec075562dc93bb0c69f37423ca2af9b48f
• Linux >= 5e8d4d36bf23bb7baf027c479d54395840219928 < e009c5f0ad634c62f5c48a41f1f3c019ecf52555
• Linux >= 5e8d4d36bf23bb7baf027c479d54395840219928 < 3660b98d1204b419f6a77e9a295f148dcf38d042
• Linux 3.15

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.