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| author | Chris Metcalf <cmetcalf@tilera.com> | 2011-05-29 12:55:44 +0200 |
|---|---|---|
| committer | David S. Miller <davem@zippy.davemloft.net> | 2011-06-01 00:11:02 +0200 |
| commit | 48bdf072c3f1f8f739f76d19c74f4c79605cac46 (patch) | |
| tree | 0cf0f1600892a781949451df0087b2407522a5ed /net | |
| parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.... (diff) | |
| download | linux-48bdf072c3f1f8f739f76d19c74f4c79605cac46.tar.xz linux-48bdf072c3f1f8f739f76d19c74f4c79605cac46.zip | |
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.c | 15 |
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 { |