This is a note to let you know that I've just added the patch titled
net/smc: fix potential panic dues to unprotected smc_llc_srv_add_link()
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-smc-fix-potential-panic-dues-to-unprotected-smc_.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit bf665239f4fd4b2466a0f2f0fdb0cf1772740dfe
Author: D. Wythe <alibuda@xxxxxxxxxxxxxxxxx>
Date: Thu Feb 16 14:37:36 2023 +0800
net/smc: fix potential panic dues to unprotected smc_llc_srv_add_link()
[ Upstream commit e40b801b3603a8f90b46acbacdea3505c27f01c0 ]
There is a certain chance to trigger the following panic:
PID: 5900 TASK: ffff88c1c8af4100 CPU: 1 COMMAND: "kworker/1:48"
#0 [ffff9456c1cc79a0] machine_kexec at ffffffff870665b7
#1 [ffff9456c1cc79f0] __crash_kexec at ffffffff871b4c7a
#2 [ffff9456c1cc7ab0] crash_kexec at ffffffff871b5b60
#3 [ffff9456c1cc7ac0] oops_end at ffffffff87026ce7
#4 [ffff9456c1cc7ae0] page_fault_oops at ffffffff87075715
#5 [ffff9456c1cc7b58] exc_page_fault at ffffffff87ad0654
#6 [ffff9456c1cc7b80] asm_exc_page_fault at ffffffff87c00b62
[exception RIP: ib_alloc_mr+19]
RIP: ffffffffc0c9cce3 RSP: ffff9456c1cc7c38 RFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000004
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88c1ea281d00 R8: 000000020a34ffff R9: ffff88c1350bbb20
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000010 R14: ffff88c1ab040a50 R15: ffff88c1ea281d00
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#7 [ffff9456c1cc7c60] smc_ib_get_memory_region at ffffffffc0aff6df [smc]
#8 [ffff9456c1cc7c88] smcr_buf_map_link at ffffffffc0b0278c [smc]
#9 [ffff9456c1cc7ce0] __smc_buf_create at ffffffffc0b03586 [smc]
The reason here is that when the server tries to create a second link,
smc_llc_srv_add_link() has no protection and may add a new link to
link group. This breaks the security environment protected by
llc_conf_mutex.
Fixes: 2d2209f20189 ("net/smc: first part of add link processing as SMC server")
Signed-off-by: D. Wythe <alibuda@xxxxxxxxxxxxxxxxx>
Reviewed-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx>
Reviewed-by: Wenjia Zhang <wenjia@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index e12d4fa5aece6..d9413d43b1045 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1826,8 +1826,10 @@ static int smcr_serv_conf_first_link(struct smc_sock *smc)
smc_llc_link_active(link);
smcr_lgr_set_type(link->lgr, SMC_LGR_SINGLE);
+ mutex_lock(&link->lgr->llc_conf_mutex);
/* initial contact - try to establish second link */
smc_llc_srv_add_link(link, NULL);
+ mutex_unlock(&link->lgr->llc_conf_mutex);
return 0;
}
