Description
In the Linux kernel, the following vulnerability has been resolved: net: team: fix NULL pointer dereference in team_xmit during mode change __team_change_mode() clears team->ops with memset() before restoring safe dummy handlers via team_adjust_ops(). A concurrent team_xmit() running under RCU on another CPU can read team->ops.transmit during this window and call a NULL function pointer, crashing the kernel. The race requires a mode change (CAP_NET_ADMIN) concurrent with transmit on the team device. BUG: kernel NULL pointer dereference, address: 0000000000000000 Oops: 0010 [#1] SMP KASAN NOPTI RIP: 0010:0x0 Call Trace: team_xmit (drivers/net/team/team_core.c:1853) dev_hard_start_xmit (net/core/dev.c:3904) __dev_queue_xmit (net/core/dev.c:4871) packet_sendmsg (net/packet/af_packet.c:3109) __sys_sendto (net/socket.c:2265) The original code assumed that no ports means no traffic, so mode changes could freely memset()/memcpy() the ops. AF_PACKET with forced carrier breaks that assumption. Prevent the race instead of making it safe: replace memset()/memcpy() with per-field updates that never touch transmit or receive. Those two handlers are managed solely by team_adjust_ops(), which already installs dummies when tx_en_port_count == 0 (always true during mode change since no ports are present). WRITE_ONCE/READ_ONCE prevent store/load tearing on the handler pointers. synchronize_net() before exit_op() drains in-flight readers that may still reference old mode state from before port removal switched the handlers to dummies.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 to < d61bf3bc17de1e18cbdac94cf5389bb9dc2ddfe7affected3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 to < ac342f86638f5e184c8511cff12a421aea56acc6affected3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 to < a879f78c478cee77f4bd43e92225a640c23f45d4affected3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 to < 9486377e5e971988a3add171c398eb654a866fabaffected3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 to < cde5c7f0286c4203d0abc7248201542aa8bf33bbaffected3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 to < 03e9405c518c4d61f28079492f252d6d4e2bac5caffected3d249d4ca7d0ed6629a135ea1ea21c72286c0d80 to < 25fe708bbc59289d3d1ea4b126fbc1b460a072a5affected
Linux Linux
Default version status: affected
3.3affected0 to < 3.3unaffected5.10.273 to ≤ 5.10.*unaffected5.15.224 to ≤ 5.15.*unaffected6.1.191 to ≤ 6.1.*unaffected6.6.160 to ≤ 6.6.*unaffected6.12.114 to ≤ 6.12.*unaffected6.18.35 to ≤ 6.18.*unaffected7.1 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/d61bf3bc17de1e18cbdac94cf5389bb9dc2ddfe7 ↗
- https://git.kernel.org/stable/c/ac342f86638f5e184c8511cff12a421aea56acc6 ↗
- https://git.kernel.org/stable/c/a879f78c478cee77f4bd43e92225a640c23f45d4 ↗
- https://git.kernel.org/stable/c/9486377e5e971988a3add171c398eb654a866fab ↗
- https://git.kernel.org/stable/c/cde5c7f0286c4203d0abc7248201542aa8bf33bb ↗
- https://git.kernel.org/stable/c/03e9405c518c4d61f28079492f252d6d4e2bac5c ↗
- https://git.kernel.org/stable/c/25fe708bbc59289d3d1ea4b126fbc1b460a072a5 ↗