Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: net: qrtr: fix refcount saturation and potential UAF in qrtr_port_remove In qrtr_port_remove(), the socket reference count is decremented via __sock_put() before the port is removed from the qrtr_ports XArray and before the RCU grace period elapses. This breaks the fundamental RCU update paradigm. It exposes a race window where a concurrent RCU reader (such as qrtr_reset_ports() or qrtr_port_lookup()) can obtain a pointer to the socket from the XArray, and attempt to call sock_hold() on a socket whose reference count has already dropped to zero. This exact race condition was hit during syzkaller fuzzing, leading to the following refcount saturation warning and a potential Use-After-Free: refcount_t: saturated; leaking memory. WARNING: CPU: 3 PID: 1273 at lib/refcount.c:22 refcount_warn_saturate+0xae/0x1d0 Modules linked in: qrtr(+) bochs drm_shmem_helper ... Call Trace: <TASK> qrtr_reset_ports net/qrtr/af_qrtr.c:768 [inline] [qrtr] __qrtr_bind.isra.0+0x48b/0x570 net/qrtr/af_qrtr.c:805 [qrtr] qrtr_bind+0x17d/0x210 net/qrtr/af_qrtr.c:901 [qrtr] kernel_bind+0xe4/0x120 net/socket.c:3592 qrtr_ns_init+0x1a6/0x380 net/qrtr/ns.c:715 [qrtr] qrtr_proto_init+0x3b/0xff0 net/qrtr/af_qrtr.c:169 [qrtr] do_one_initcall+0xf5/0x5e0 init/main.c:1283 ... </TASK> Fix this by deferring the reference count decrement until after the xa_erase() and the synchronize_rcu() complete. (Note: The v1 of this patch incorrectly replaced __sock_put() with sock_put(). As Simon Horman pointed out, the callers of qrtr_port_remove() still hold a reference to the socket, so freeing the socket memory here would lead to a subsequent UAF in the caller. Thus, the __sock_put() is kept, but only repositioned to close the RCU race.)
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected bdabad3e363d825ddf9679dd431cca0b2c30f881 before 2aa4c12723fe432e623462a3be42a197a128722b; affected bdabad3e363d825ddf9679dd431cca0b2c30f881 before 03bfa95e452e2b6ccd76a332060ae4feaf5ad84d; affected bdabad3e363d825ddf9679dd431cca0b2c30f881 before 474293d90880622fde9d2430fb0165767090f7b3; affected bdabad3e363d825ddf9679dd431cca0b2c30f881 before 2047c2aa0963bb2872fd722300a15bcb441a4c00; affected bdabad3e363d825ddf9679dd431cca0b2c30f881 before 7de2d447072be3b1a76793f034432338fc9c494b; affected bdabad3e363d825ddf9679dd431cca0b2c30f881 before ab269990ed58143a92a263be1bee626d82ac03da; affected bdabad3e363d825ddf9679dd431cca0b2c30f881 before 3b20ec8f31e8a6a6782243f473b0abd3463621df; affected bdabad3e363d825ddf9679dd431cca0b2c30f881 before a2171131ecda1ed61a594a1eb715e75fdad0fef5 |
| Linux / Linux | affected 4.7; unaffected 0 before 4.7; unaffected 5.10.259 through 5.10.*; unaffected 5.15.210 through 5.15.*; unaffected 6.1.176 through 6.1.*; unaffected 6.6.143 through 6.6.*; unaffected 6.12.94 through 6.12.*; unaffected 6.18.36 through 6.18.*; unaffected 7.0.13 through 7.0.*; unaffected 7.1 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/2aa4c12723fe432e623462a3be42a197a128722b
- https://git.kernel.org/stable/c/03bfa95e452e2b6ccd76a332060ae4feaf5ad84d
- https://git.kernel.org/stable/c/474293d90880622fde9d2430fb0165767090f7b3
- https://git.kernel.org/stable/c/2047c2aa0963bb2872fd722300a15bcb441a4c00
- https://git.kernel.org/stable/c/7de2d447072be3b1a76793f034432338fc9c494b
- https://git.kernel.org/stable/c/ab269990ed58143a92a263be1bee626d82ac03da
- https://git.kernel.org/stable/c/3b20ec8f31e8a6a6782243f473b0abd3463621df
- https://git.kernel.org/stable/c/a2171131ecda1ed61a594a1eb715e75fdad0fef5
ADP enrichment
No English description supplied.
No English description supplied.
No references supplied.