Patch "sctp: use the correct skb for security_sctp_assoc_request" has been added to the 5.17-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    sctp: use the correct skb for security_sctp_assoc_request

to the 5.17-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sctp-use-the-correct-skb-for-security_sctp_assoc_req.patch
and it can be found in the queue-5.17 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 2d128bd144a7b26fb8cca7c6f894bc7e140c39fe
Author: Xin Long <lucien.xin@xxxxxxxxx>
Date:   Thu Apr 7 09:24:22 2022 -0400

    sctp: use the correct skb for security_sctp_assoc_request
    
    [ Upstream commit e2d88f9ce678cd33763826ae2f0412f181251314 ]
    
    Yi Chen reported an unexpected sctp connection abort, and it occurred when
    COOKIE_ECHO is bundled with DATA Fragment by SCTP HW GSO. As the IP header
    is included in chunk->head_skb instead of chunk->skb, it failed to check
    IP header version in security_sctp_assoc_request().
    
    According to Ondrej, SELinux only looks at IP header (address and IPsec
    options) and XFRM state data, and these are all included in head_skb for
    SCTP HW GSO packets. So fix it by using head_skb when calling
    security_sctp_assoc_request() in processing COOKIE_ECHO.
    
    v1->v2:
      - As Ondrej noticed, chunk->head_skb should also be used for
        security_sctp_assoc_established() in sctp_sf_do_5_1E_ca().
    
    Fixes: e215dab1c490 ("security: call security_sctp_assoc_request in sctp_sf_do_5_1D_ce")
    Reported-by: Yi Chen <yiche@xxxxxxxxxx>
    Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
    Reviewed-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
    Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
    Link: https://lore.kernel.org/r/71becb489e51284edf0c11fc15246f4ed4cef5b6.1649337862.git.lucien.xin@xxxxxxxxx
    Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 7f342bc12735..52edee1322fc 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -781,7 +781,7 @@ enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
 		}
 	}
 
-	if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
+	if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) {
 		sctp_association_free(new_asoc);
 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 	}
@@ -932,7 +932,7 @@ enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
 
 	/* Set peer label for connection. */
 	if (security_sctp_assoc_established((struct sctp_association *)asoc,
-					    chunk->skb))
+					    chunk->head_skb ?: chunk->skb))
 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 
 	/* Verify that the chunk length for the COOKIE-ACK is OK.
@@ -2262,7 +2262,7 @@ enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
 	}
 
 	/* Update socket peer label if first association. */
-	if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
+	if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) {
 		sctp_association_free(new_asoc);
 		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
 	}