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path: root/net/xfrm/xfrm_replay.c
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2013-01-18net/xfrm/xfrm_replay: avoid division by zeroNickolai Zeldovich
All of the xfrm_replay->advance functions in xfrm_replay.c check if x->replay_esn->replay_window is zero (and return if so). However, one of them, xfrm_replay_advance_bmp(), divides by that value (in the '%' operator) before doing the check, which can potentially trigger a divide-by-zero exception. Some compilers will also assume that the earlier division means the value cannot be zero later, and thus will eliminate the subsequent zero check as dead code. This patch moves the division to after the check. Signed-off-by: Nickolai Zeldovich <nickolai@csail.mit.edu> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2012-11-08xfrm: remove redundant replay_esn checkUlrich Weber
x->replay_esn is already checked in if clause, so remove check and ident properly Signed-off-by: Ulrich Weber <ulrich.weber@sophos.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2012-09-04xfrm: Workaround incompatibility of ESN and async cryptoSteffen Klassert
ESN for esp is defined in RFC 4303. This RFC assumes that the sequence number counters are always up to date. However, this is not true if an async crypto algorithm is employed. If the sequence number counters are not up to date on sequence number check, we may incorrectly update the upper 32 bit of the sequence number. This leads to a DOS. We workaround this by comparing the upper sequence number, (used for authentication) with the upper sequence number computed after the async processing. We drop the packet if these numbers are different. To do this, we introduce a recheck function that does this check in the ESN case. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-03-22xfrm: Access the replay notify functions via the registered callbacksSteffen Klassert
We call the wrong replay notify function when we use ESN replay handling. This leads to the fact that we don't send notifications if we use ESN. Fix this by calling the registered callbacks instead of xfrm_replay_notify(). Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-10-31net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modulesPaul Gortmaker
These files are non modular, but need to export symbols using the macros now living in export.h -- call out the include so that things won't break when we remove the implicit presence of module.h from everywhere. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-18xfrm: Simplify the replay check and advance functionsSteffen Klassert
The replay check and replay advance functions had some code duplications. This patch removes the duplications. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-06-07xfrm: Fix off by one in the replay advance functionsSteffen Klassert
We may write 4 byte too much when we reinitialize the anti replay window in the replay advance functions. This patch fixes this by adjusting the last index of the initialization loop. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-05-10xfrm: Don't allow esn with disabled anti replay detectionSteffen Klassert
Unlike the standard case, disabled anti replay detection needs some nontrivial extra treatment on ESN. RFC 4303 states: Note: If a receiver chooses to not enable anti-replay for an SA, then the receiver SHOULD NOT negotiate ESN in an SA management protocol. Use of ESN creates a need for the receiver to manage the anti-replay window (in order to determine the correct value for the high-order bits of the ESN, which are employed in the ICV computation), which is generally contrary to the notion of disabling anti-replay for an SA. So return an error if an ESN state with disabled anti replay detection is inserted for now and add the extra treatment later if we need it. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-04-26xfrm: Fix replay window size calculation on initializationSteffen Klassert
On replay initialization, we compute the size of the replay buffer to see if the replay window fits into the buffer. This computation lacks a mutliplication by 8 because we need the size in bit, not in byte. So we might return an error even though the replay window would fit into the buffer. This patch fixes this issue. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-03-28xfrm: Move the test on replay window size into the replay check functionsSteffen Klassert
As it is, the replay check is just performed if the replay window of the legacy implementation is nonzero. So we move the test on a nonzero replay window inside the replay check functions to be sure we are testing for the right implementation. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-03-13xfrm: Add support for IPsec extended sequence numbersSteffen Klassert
This patch adds support for IPsec extended sequence numbers (esn) as defined in RFC 4303. The bits to manage the anti-replay window are based on a patch from Alex Badea. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-03-13xfrm: Support anti-replay window size bigger than 32 packetsSteffen Klassert
As it is, the anti-replay bitmap in struct xfrm_replay_state can only accomodate 32 packets. Even though it is possible to configure anti-replay window sizes up to 255 packets from userspace. So we reject any packet with a sequence number within the configured window but outside the bitmap. With this patch, we represent the anti-replay window as a bitmap of variable length that can be accessed via the new struct xfrm_replay_state_esn. Thus, we have no limit on the window size anymore. To use the new anti-replay window implementantion, new userspace tools are required. We leave the old implementation untouched to stay in sync with old userspace tools. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-03-13xfrm: Move IPsec replay detection functions to a separate fileSteffen Klassert
To support multiple versions of replay detection, we move the replay detection functions to a separate file and make them accessible via function pointers contained in the struct xfrm_replay. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>