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
| ||
|
Date: Tue, 13 May 2008 12:07:35 +0800 From: "Yang, Graf" <Graf.Yang@...log.com> To: "Marcel Holtmann" <marcel@...tmann.org>, "Bryan Wu" <cooloney@...nel.org> Cc: <samuel@...tiz.org>, <irda-users@...ts.sourceforge.net>, <linux-kernel@...r.kernel.org>, "Graf Yang" <graf.yang@...log.com> Subject: RE: [PATCH 1/1] [net/irda]: Fix a misalign access issue. Hi Marcel, The root cause is __u8 hints[2] are unaligned because of __u8 charset defined in file include/linux/irda.h:132 struct irda_device_info { __u32 saddr; /* Address of local interface */ __u32 daddr; /* Address of remote device */ char info[22]; /* Description */ __u8 charset; /* Charset used for description */ __u8 hints[2]; /* Hint bits */ }; And code may access hints[2] as u16. As put_unaligned/get_unaligned would set/get value through several instructions which decreases the performance. So I'd like to modify the irda_device_info instead of using put_unaligned/get_unaligned in irlmp.c/discovery.c. I have tried struct irda_device_info { __u32 saddr; /* Address of local interface */ __u32 daddr; /* Address of remote device */ char info[22]; /* Description */ __u8 charset; /* Charset used for description */ __u8 reserve; /* For align data */ __u8 hints[2]; /* Hint bits */ }; It works with my irda driver. Can I modify it like this? There are many methods to modify this structure, which method are better? It seems u16ho is useless, I would remove them from net/irda. I can't enable irnet, so didn't touch net/irda/irnet/irnet_irda.c. Would you give some information about how to enable irnet? BRs, Graf -----Original Message----- From: Marcel Holtmann [mailto:marcel@...tmann.org] Sent: Mon 5/12/2008 9:15 PM To: Bryan Wu Cc: samuel@...tiz.org; irda-users@...ts.sourceforge.net; linux-kernel@...r.kernel.org; Graf Yang Subject: Re: [PATCH 1/1] [net/irda]: Fix a misalign access issue. Hi Bryan, > From: Graf Yang <graf.yang@...log.com> > > Signed-off-by: Graf Yang <graf.yang@...log.com> > Signed-off-by: Bryan Wu <cooloney@...nel.org> > --- > net/irda/discovery.c | 8 +++++--- > net/irda/irlmp.c | 2 +- > 2 files changed, 6 insertions(+), 4 deletions(-) > > diff --git a/net/irda/discovery.c b/net/irda/discovery.c > index bfacef8..a6f99b5 100644 > --- a/net/irda/discovery.c > +++ b/net/irda/discovery.c > @@ -40,6 +40,8 @@ > > #include <net/irda/discovery.h> > > +#include <asm/unaligned.h> > + > /* > * Function irlmp_add_discovery (cachelog, discovery) > * > @@ -87,7 +89,7 @@ void irlmp_add_discovery(hashbin_t *cachelog, discovery_t *new) > */ > hashbin_remove_this(cachelog, (irda_queue_t *) node); > /* Check if hints bits are unchanged */ > - if(u16ho(node->data.hints) == u16ho(new->data.hints)) > + if (get_unaligned((__u16 *)node->data.hints) == get_unaligned((__u16 *)new->data.hints)) > /* Set time of first discovery for this node */ > new->firststamp = node->firststamp; > kfree(node); > @@ -281,9 +283,9 @@ struct irda_device_info *irlmp_copy_discoveries(hashbin_t *log, int *pn, > /* Mask out the ones we don't want : > * We want to match the discovery mask, and to get only > * the most recent one (unless we want old ones) */ > - if ((u16ho(discovery->data.hints) & mask) && > + if ((get_unaligned((__u16 *)discovery->data.hints) & mask) && > ((old_entries) || > - ((jiffies - discovery->firststamp) < j_timeout)) ) { > + ((jiffies - discovery->firststamp) < j_timeout))) { > /* Create buffer as needed. > * As this function get called a lot and most time > * we don't have anything to put in the log (we are > diff --git a/net/irda/irlmp.c b/net/irda/irlmp.c > index 1f81f8e..7b95cd6 100644 > --- a/net/irda/irlmp.c > +++ b/net/irda/irlmp.c > @@ -1086,7 +1086,7 @@ discovery_t *irlmp_get_discovery_response(void) > > IRDA_ASSERT(irlmp != NULL, return NULL;); > > - u16ho(irlmp->discovery_rsp.data.hints) = irlmp->hints.word; > + put_unaligned(irlmp->hints.word, (__u16 *)irlmp->discovery_rsp.data.hints); > > /* > * Set character set for device name (we use ASCII), and what about net/irda/irnet/irnet_irda.c and why not also kill the u16ho macro at the same time. Regards Marcel -- 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/
Powered by blists - more mailing lists