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| author | Philippe De Muyter <phdm@macqel.be> | 2005-11-08 09:40:26 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2005-11-08 09:40:26 -0800 |
| commit | 6722e78c90054101e6797d5944cdc81af9897a0a (patch) | |
| tree | 853b2618ecf9ec9e051ad49f1cca64d3854544a9 /drivers/net/ppp_async.c | |
| parent | dc8103f25fd7cfac2c2b295f33edc10f255b4c80 (diff) | |
| download | lwn-6722e78c90054101e6797d5944cdc81af9897a0a.tar.gz lwn-6722e78c90054101e6797d5944cdc81af9897a0a.zip | |
[PPP]: handle misaligned accesses
From: "Philippe De Muyter" <phdm@macqel.be>
This patch avoids ppp-generated kernel crashes on machines where unaligned
accesses are forbidden (ie: m68000), by fixing ppp alignment setting for
reused skb's.
Signed-off-by: Philippe De Muyter <phdm@macqel.be>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ppp_async.c')
| -rw-r--r-- | drivers/net/ppp_async.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/drivers/net/ppp_async.c b/drivers/net/ppp_async.c index 59e8183c639e..400f652282d7 100644 --- a/drivers/net/ppp_async.c +++ b/drivers/net/ppp_async.c @@ -31,6 +31,7 @@ #include <linux/spinlock.h> #include <linux/init.h> #include <asm/uaccess.h> +#include <asm/string.h> #define PPP_VERSION "2.4.2" @@ -835,8 +836,11 @@ process_input_packet(struct asyncppp *ap) err: /* frame had an error, remember that, reset SC_TOSS & SC_ESCAPE */ ap->state = SC_PREV_ERROR; - if (skb) + if (skb) { + /* make skb appear as freshly allocated */ skb_trim(skb, 0); + skb_reserve(skb, - skb_headroom(skb)); + } } /* Called when the tty driver has data for us. Runs parallel with the @@ -889,10 +893,17 @@ ppp_async_input(struct asyncppp *ap, const unsigned char *buf, skb = dev_alloc_skb(ap->mru + PPP_HDRLEN + 2); if (skb == 0) goto nomem; - /* Try to get the payload 4-byte aligned */ + ap->rpkt = skb; + } + if (skb->len == 0) { + /* Try to get the payload 4-byte aligned. + * This should match the + * PPP_ALLSTATIONS/PPP_UI/compressed tests in + * process_input_packet, but we do not have + * enough chars here to test buf[1] and buf[2]. + */ if (buf[0] != PPP_ALLSTATIONS) skb_reserve(skb, 2 + (buf[0] & 1)); - ap->rpkt = skb; } if (n > skb_tailroom(skb)) { /* packet overflowed MRU */ |