| Message ID | 1371673956-471-1-git-send-email-steve.moorby@ntlworld.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Stephen Moorby <steve.moorby@ntlworld.com> Date: Wed, 19 Jun 2013 21:32:36 +0100 > This problem was discovered when a linux box was incorrectly rejecting > calls from some X.25 equipment. The problem was diagnosed to an incorrect > address length calculation in 'x25_parse_address_block', the calculation > did not account for the address digits being BCD encoded. The correct > calculation is already performed on line 155. > > Patched on linux-next 18-Jun-2013 > Tested on 2.6.32-45-generic > > Signed-off-by: Stephen Moorby <steve.moorby@ntlworld.com> This change has two problems: 1) If there is existing code that does the calculation correctly, don't get creative and express the calculation differently than the existing code. 2) If there are two places doing the same thing, write a helper function that does it in one place. The exact reason this bug exists is because of code duplication, you are making it even worse by writing the same calculation two different ways. Please fix this up and resubmit, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c index 1d964e2..eb6c1f9 100644 --- a/net/x25/af_x25.c +++ b/net/x25/af_x25.c @@ -98,7 +98,8 @@ int x25_parse_address_block(struct sk_buff *skb, } len = *skb->data; - needed = 1 + (len >> 4) + (len & 0x0f); + /* need 1 for address length + bytes for BCD encoding of 2 addresses */ + needed = 1 + (((len >> 4) + (len & 0x0f) + 1) >> 1); if (!pskb_may_pull(skb, needed)) { /* packet is too short to hold the addresses it claims
This problem was discovered when a linux box was incorrectly rejecting calls from some X.25 equipment. The problem was diagnosed to an incorrect address length calculation in 'x25_parse_address_block', the calculation did not account for the address digits being BCD encoded. The correct calculation is already performed on line 155. Patched on linux-next 18-Jun-2013 Tested on 2.6.32-45-generic Signed-off-by: Stephen Moorby <steve.moorby@ntlworld.com> --- net/x25/af_x25.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)