linux-kernel - [KJ] audit return code handling for kernel

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <200607282008.k6SK85lh009691@ra.tuxdriver.com>
Date:	Fri, 28 Jul 2006 16:08:05 -0400
From:	nhorman@...driver.com
To:	fpavlic@...ibm.com, kernel-janitors@...l.org,
	linux-kernel@...r.kernel.org, nhorman@...driver.com
Subject: [KJ] audit return code handling for kernel_thread [9/11]

Audit/Cleanup of kernel_thread calls, specifically checking of return codes.
    Problems seemed to fall into 3 main categories:
    
    1) callers of kernel_thread were inconsistent about meaning of a zero return
    code.  Some callers considered a zero return code to mean success, others took
    it to mean failure.  a zero return code, while not actually possible in the
    current implementation, should be considered a success (pid 0 is/should be
    valid). fixed all callers to treat zero return as success
    
    2) caller of kernel_thread saved return code of kernel_thread for later use
    without ever checking its value.  Callers who did this tended to assume a
    non-zero return was success, and would often wait for a completion queue to be
    woken up, implying that an error (negative return code) from kernel_thread could
    lead to deadlock.  Repaired by checking return code at call time, and setting
    saved return code to zero in the event of an error.
    
    3) callers of kernel_thread never bothered to check the return code at all.
    This can lead to seemingly unrelated errors later in execution.  Fixed by
    checking return code at call time and printing a warning message on failure.

Regards
Neil
    
Signed-off-by: Neil Horman <nhorman@...driver.com>


 drivers/s390/net/qeth_main.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/drivers/s390/net/qeth_main.c
+++ b/drivers/s390/net/qeth_main.c
@@ -1048,11 +1048,14 @@ qeth_start_kernel_thread(struct qeth_car
 		return;
 
 	if (qeth_do_start_thread(card, QETH_SET_IP_THREAD))
-		kernel_thread(qeth_register_ip_addresses, (void *)card,SIGCHLD);
+		if (kernel_thread(qeth_register_ip_addresses, (void *)card,SIGCHLD) < 0)
+			printk(KERN_WARNING "Could not start qeth register thread\n");
 	if (qeth_do_start_thread(card, QETH_SET_PROMISC_MODE_THREAD))
-		kernel_thread(qeth_set_promisc_mode, (void *)card, SIGCHLD);
+		if (kernel_thread(qeth_set_promisc_mode, (void *)card, SIGCHLD) < 0)
+			printk(KERN_WARNING "Could not start qeth prmisc thread\n");
 	if (qeth_do_start_thread(card, QETH_RECOVER_THREAD))
-		kernel_thread(qeth_recover, (void *) card, SIGCHLD);
+		if (kernel_thread(qeth_recover, (void *) card, SIGCHLD) < 0)
+			printk(KERN_WARNING "Could not start qeth recovery thread\n");
 }
 
 
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/