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authorChris Metcalf <cmetcalf@tilera.com>2011-05-29 10:55:44 +0000
committerDavid S. Miller <davem@zippy.davemloft.net>2011-05-31 15:11:02 -0700
commit48bdf072c3f1f8f739f76d19c74f4c79605cac46 (patch)
tree0cf0f1600892a781949451df0087b2407522a5ed /net/ipv4
parent11ad2f52826ac6d58d6780d3d8a3e098c88d9142 (diff)
ip_options_compile: properly handle unaligned pointer
The current code takes an unaligned pointer and does htonl() on it to make it big-endian, then does a memcpy(). The problem is that the compiler decides that since the pointer is to a __be32, it is legal to optimize the copy into a processor word store. However, on an architecture that does not handled unaligned writes in kernel space, this produces an unaligned exception fault. The solution is to track the pointer as a "char *" (which removes a bunch of unpleasant casts in any case), and then just use put_unaligned_be32() to write the value to memory. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Signed-off-by: David S. Miller <davem@zippy.davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/ip_options.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c
index c3118e1cd3bb..ec93335901dd 100644
--- a/net/ipv4/ip_options.c
+++ b/net/ipv4/ip_options.c
@@ -14,6 +14,7 @@
#include <linux/slab.h>
#include <linux/types.h>
#include <asm/uaccess.h>
+#include <asm/unaligned.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/icmp.h>
@@ -350,7 +351,7 @@ int ip_options_compile(struct net *net,
goto error;
}
if (optptr[2] <= optlen) {
- __be32 *timeptr = NULL;
+ unsigned char *timeptr = NULL;
if (optptr[2]+3 > optptr[1]) {
pp_ptr = optptr + 2;
goto error;
@@ -359,7 +360,7 @@ int ip_options_compile(struct net *net,
case IPOPT_TS_TSONLY:
opt->ts = optptr - iph;
if (skb)
- timeptr = (__be32*)&optptr[optptr[2]-1];
+ timeptr = &optptr[optptr[2]-1];
opt->ts_needtime = 1;
optptr[2] += 4;
break;
@@ -371,7 +372,7 @@ int ip_options_compile(struct net *net,
opt->ts = optptr - iph;
if (rt) {
memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
- timeptr = (__be32*)&optptr[optptr[2]+3];
+ timeptr = &optptr[optptr[2]+3];
}
opt->ts_needaddr = 1;
opt->ts_needtime = 1;
@@ -389,7 +390,7 @@ int ip_options_compile(struct net *net,
if (inet_addr_type(net, addr) == RTN_UNICAST)
break;
if (skb)
- timeptr = (__be32*)&optptr[optptr[2]+3];
+ timeptr = &optptr[optptr[2]+3];
}
opt->ts_needtime = 1;
optptr[2] += 8;
@@ -403,10 +404,10 @@ int ip_options_compile(struct net *net,
}
if (timeptr) {
struct timespec tv;
- __be32 midtime;
+ u32 midtime;
getnstimeofday(&tv);
- midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC);
- memcpy(timeptr, &midtime, sizeof(__be32));
+ midtime = (tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC;
+ put_unaligned_be32(midtime, timeptr);
opt->is_changed = 1;
}
} else {