From 814596495dd2b9d4aab92d8f89cf19060d25d2ea Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 14 May 2018 20:09:24 -0700 Subject: cfg80211: further limit wiphy names to 64 bytes wiphy names were recently limited to 128 bytes by commit a7cfebcb7594 ("cfg80211: limit wiphy names to 128 bytes"). As it turns out though, this isn't sufficient because dev_vprintk_emit() needs the syslog header string "SUBSYSTEM=ieee80211\0DEVICE=+ieee80211:$devname" to fit into 128 bytes. This triggered the "device/subsystem name too long" WARN when the device name was >= 90 bytes. As before, this was reproduced by syzbot by sending an HWSIM_CMD_NEW_RADIO command to the MAC80211_HWSIM generic netlink family. Fix it by further limiting wiphy names to 64 bytes. Reported-by: syzbot+e64565577af34b3768dc@syzkaller.appspotmail.com Fixes: a7cfebcb7594 ("cfg80211: limit wiphy names to 128 bytes") Signed-off-by: Eric Biggers Signed-off-by: Johannes Berg --- include/uapi/linux/nl80211.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/uapi') diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h index 9c3630146cec..271b93783d28 100644 --- a/include/uapi/linux/nl80211.h +++ b/include/uapi/linux/nl80211.h @@ -2698,7 +2698,7 @@ enum nl80211_attrs { #define NL80211_ATTR_KEYS NL80211_ATTR_KEYS #define NL80211_ATTR_FEATURE_FLAGS NL80211_ATTR_FEATURE_FLAGS -#define NL80211_WIPHY_NAME_MAXLEN 128 +#define NL80211_WIPHY_NAME_MAXLEN 64 #define NL80211_MAX_SUPP_RATES 32 #define NL80211_MAX_SUPP_HT_RATES 77 -- cgit v1.2.3 From af8d3c7c001ae7df1ed2b2715f058113efc86187 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 23 May 2018 14:37:38 -0700 Subject: ppp: remove the PPPIOCDETACH ioctl The PPPIOCDETACH ioctl effectively tries to "close" the given ppp file before f_count has reached 0, which is fundamentally a bad idea. It does check 'f_count < 2', which excludes concurrent operations on the file since they would only be possible with a shared fd table, in which case each fdget() would take a file reference. However, it fails to account for the fact that even with 'f_count == 1' the file can still be linked into epoll instances. As reported by syzbot, this can trivially be used to cause a use-after-free. Yet, the only known user of PPPIOCDETACH is pppd versions older than ppp-2.4.2, which was released almost 15 years ago (November 2003). Also, PPPIOCDETACH apparently stopped working reliably at around the same time, when the f_count check was added to the kernel, e.g. see https://lkml.org/lkml/2002/12/31/83. Also, the current 'f_count < 2' check makes PPPIOCDETACH only work in single-threaded applications; it always fails if called from a multithreaded application. All pppd versions released in the last 15 years just close() the file descriptor instead. Therefore, instead of hacking around this bug by exporting epoll internals to modules, and probably missing other related bugs, just remove the PPPIOCDETACH ioctl and see if anyone actually notices. Leave a stub in place that prints a one-time warning and returns EINVAL. Reported-by: syzbot+16363c99d4134717c05b@syzkaller.appspotmail.com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Biggers Acked-by: Paul Mackerras Reviewed-by: Guillaume Nault Tested-by: Guillaume Nault Signed-off-by: David S. Miller --- Documentation/networking/ppp_generic.txt | 6 ------ drivers/net/ppp/ppp_generic.c | 27 +++++---------------------- include/uapi/linux/ppp-ioctl.h | 2 +- 3 files changed, 6 insertions(+), 29 deletions(-) (limited to 'include/uapi') diff --git a/Documentation/networking/ppp_generic.txt b/Documentation/networking/ppp_generic.txt index 091d20273dcb..61daf4b39600 100644 --- a/Documentation/networking/ppp_generic.txt +++ b/Documentation/networking/ppp_generic.txt @@ -300,12 +300,6 @@ unattached instance are: The ioctl calls available on an instance of /dev/ppp attached to a channel are: -* PPPIOCDETACH detaches the instance from the channel. This ioctl is - deprecated since the same effect can be achieved by closing the - instance. In order to prevent possible races this ioctl will fail - with an EINVAL error if more than one file descriptor refers to this - instance (i.e. as a result of dup(), dup2() or fork()). - * PPPIOCCONNECT connects this channel to a PPP interface. The argument should point to an int containing the interface unit number. It will return an EINVAL error if the channel is already diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index dc7c7ec43202..02ad03a2fab7 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -605,30 +605,13 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) if (cmd == PPPIOCDETACH) { /* - * We have to be careful here... if the file descriptor - * has been dup'd, we could have another process in the - * middle of a poll using the same file *, so we had - * better not free the interface data structures - - * instead we fail the ioctl. Even in this case, we - * shut down the interface if we are the owner of it. - * Actually, we should get rid of PPPIOCDETACH, userland - * (i.e. pppd) could achieve the same effect by closing - * this fd and reopening /dev/ppp. + * PPPIOCDETACH is no longer supported as it was heavily broken, + * and is only known to have been used by pppd older than + * ppp-2.4.2 (released November 2003). */ + pr_warn_once("%s (%d) used obsolete PPPIOCDETACH ioctl\n", + current->comm, current->pid); err = -EINVAL; - if (pf->kind == INTERFACE) { - ppp = PF_TO_PPP(pf); - rtnl_lock(); - if (file == ppp->owner) - unregister_netdevice(ppp->dev); - rtnl_unlock(); - } - if (atomic_long_read(&file->f_count) < 2) { - ppp_release(NULL, file); - err = 0; - } else - pr_warn("PPPIOCDETACH file->f_count=%ld\n", - atomic_long_read(&file->f_count)); goto out; } diff --git a/include/uapi/linux/ppp-ioctl.h b/include/uapi/linux/ppp-ioctl.h index b19a9c249b15..784c2e3e572e 100644 --- a/include/uapi/linux/ppp-ioctl.h +++ b/include/uapi/linux/ppp-ioctl.h @@ -106,7 +106,7 @@ struct pppol2tp_ioc_stats { #define PPPIOCGIDLE _IOR('t', 63, struct ppp_idle) /* get idle time */ #define PPPIOCNEWUNIT _IOWR('t', 62, int) /* create new ppp unit */ #define PPPIOCATTACH _IOW('t', 61, int) /* attach to ppp unit */ -#define PPPIOCDETACH _IOW('t', 60, int) /* detach from ppp unit/chan */ +#define PPPIOCDETACH _IOW('t', 60, int) /* obsolete, do not use */ #define PPPIOCSMRRU _IOW('t', 59, int) /* set multilink MRU */ #define PPPIOCCONNECT _IOW('t', 58, int) /* connect channel to unit */ #define PPPIOCDISCONN _IO('t', 57) /* disconnect channel */ -- cgit v1.2.3