| From | Andi Kleen <> | Subject | [PATCH] [113/275] sctp: Fix out-of-bounds reading in sctp_asoc_get_hmac() | Date | Wed, 30 Mar 2011 14:05:52 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Dan Rosenberg <drosenberg@vsecurity.com>
commit 51e97a12bef19b7e43199fc153cf9bd5f2140362 upstream.
The sctp_asoc_get_hmac() function iterates through a peer's hmac_ids array and attempts to ensure that only a supported hmac entry is returned. The current code fails to do this properly - if the last id in the array is out of range (greater than SCTP_AUTH_HMAC_ID_MAX), the id integer remains set after exiting the loop, and the address of an out-of-bounds entry will be returned and subsequently used in the parent function, causing potentially ugly memory corruption. This patch resets the id integer to 0 on encountering an invalid id so that NULL will be returned after finishing the loop if no valid ids are found.
Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Acked-by: Vlad Yasevich <vladislav.yasevich@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andi Kleen <ak@linux.intel.com>
--- net/sctp/auth.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
Index: linux-2.6.35.y/net/sctp/auth.c =================================================================== --- linux-2.6.35.y.orig/net/sctp/auth.c 2011-03-29 22:51:23.475122499 -0700 +++ linux-2.6.35.y/net/sctp/auth.c 2011-03-29 23:03:00.538286398 -0700 @@ -543,16 +543,20 @@ id = ntohs(hmacs->hmac_ids[i]); /* Check the id is in the supported range */ - if (id > SCTP_AUTH_HMAC_ID_MAX) + if (id > SCTP_AUTH_HMAC_ID_MAX) { + id = 0; continue; + } /* See is we support the id. Supported IDs have name and * length fields set, so that we can allocated and use * them. We can safely just check for name, for without the * name, we can't allocate the TFM. */ - if (!sctp_hmac_list[id].hmac_name) + if (!sctp_hmac_list[id].hmac_name) { + id = 0; continue; + } break; }
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