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authorChris Metcalf <cmetcalf@tilera.com>2011-05-29 06:55:44 -0400
committerDavid S. Miller <davem@zippy.davemloft.net>2011-05-31 18:11:02 -0400
commit48bdf072c3f1f8f739f76d19c74f4c79605cac46 (patch)
tree0cf0f1600892a781949451df0087b2407522a5ed /net
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')
-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 @@
14#include <linux/slab.h> 14#include <linux/slab.h>
15#include <linux/types.h> 15#include <linux/types.h>
16#include <asm/uaccess.h> 16#include <asm/uaccess.h>
17#include <asm/unaligned.h>
17#include <linux/skbuff.h> 18#include <linux/skbuff.h>
18#include <linux/ip.h> 19#include <linux/ip.h>
19#include <linux/icmp.h> 20#include <linux/icmp.h>
@@ -350,7 +351,7 @@ int ip_options_compile(struct net *net,
350 goto error; 351 goto error;
351 } 352 }
352 if (optptr[2] <= optlen) { 353 if (optptr[2] <= optlen) {
353 __be32 *timeptr = NULL; 354 unsigned char *timeptr = NULL;
354 if (optptr[2]+3 > optptr[1]) { 355 if (optptr[2]+3 > optptr[1]) {
355 pp_ptr = optptr + 2; 356 pp_ptr = optptr + 2;
356 goto error; 357 goto error;
@@ -359,7 +360,7 @@ int ip_options_compile(struct net *net,
359 case IPOPT_TS_TSONLY: 360 case IPOPT_TS_TSONLY:
360 opt->ts = optptr - iph; 361 opt->ts = optptr - iph;
361 if (skb) 362 if (skb)
362 timeptr = (__be32*)&optptr[optptr[2]-1]; 363 timeptr = &optptr[optptr[2]-1];
363 opt->ts_needtime = 1; 364 opt->ts_needtime = 1;
364 optptr[2] += 4; 365 optptr[2] += 4;
365 break; 366 break;
@@ -371,7 +372,7 @@ int ip_options_compile(struct net *net,
371 opt->ts = optptr - iph; 372 opt->ts = optptr - iph;
372 if (rt) { 373 if (rt) {
373 memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4); 374 memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
374 timeptr = (__be32*)&optptr[optptr[2]+3]; 375 timeptr = &optptr[optptr[2]+3];
375 } 376 }
376 opt->ts_needaddr = 1; 377 opt->ts_needaddr = 1;
377 opt->ts_needtime = 1; 378 opt->ts_needtime = 1;
@@ -389,7 +390,7 @@ int ip_options_compile(struct net *net,
389 if (inet_addr_type(net, addr) == RTN_UNICAST) 390 if (inet_addr_type(net, addr) == RTN_UNICAST)
390 break; 391 break;
391 if (skb) 392 if (skb)
392 timeptr = (__be32*)&optptr[optptr[2]+3]; 393 timeptr = &optptr[optptr[2]+3];
393 } 394 }
394 opt->ts_needtime = 1; 395 opt->ts_needtime = 1;
395 optptr[2] += 8; 396 optptr[2] += 8;
@@ -403,10 +404,10 @@ int ip_options_compile(struct net *net,
403 } 404 }
404 if (timeptr) { 405 if (timeptr) {
405 struct timespec tv; 406 struct timespec tv;
406 __be32 midtime; 407 u32 midtime;
407 getnstimeofday(&tv); 408 getnstimeofday(&tv);
408 midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC); 409 midtime = (tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC;
409 memcpy(timeptr, &midtime, sizeof(__be32)); 410 put_unaligned_be32(midtime, timeptr);
410 opt->is_changed = 1; 411 opt->is_changed = 1;
411 } 412 }
412 } else { 413 } else {