Patch "cipso: fix total option length computation" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    cipso: fix total option length computation

to the 5.10-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:
     cipso-fix-total-option-length-computation.patch
and it can be found in the queue-5.10 subdirectory.

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



commit cc54163f5cf02a4bf54b96d7e05cee5eadd0a60e
Author: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
Date:   Fri Jun 7 18:07:52 2024 +0200

    cipso: fix total option length computation
    
    [ Upstream commit 9f36169912331fa035d7b73a91252d7c2512eb1a ]
    
    As evident from the definition of ip_options_get(), the IP option
    IPOPT_END is used to pad the IP option data array, not IPOPT_NOP. Yet
    the loop that walks the IP options to determine the total IP options
    length in cipso_v4_delopt() doesn't take IPOPT_END into account.
    
    Fix it by recognizing the IPOPT_END value as the end of actual options.
    
    Fixes: 014ab19a69c3 ("selinux: Set socket NetLabel based on connection endpoint")
    Signed-off-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index d4a4160159a92..c5da958e3bbdb 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -2016,12 +2016,16 @@ static int cipso_v4_delopt(struct ip_options_rcu __rcu **opt_ptr)
 		 * from there we can determine the new total option length */
 		iter = 0;
 		optlen_new = 0;
-		while (iter < opt->opt.optlen)
-			if (opt->opt.__data[iter] != IPOPT_NOP) {
+		while (iter < opt->opt.optlen) {
+			if (opt->opt.__data[iter] == IPOPT_END) {
+				break;
+			} else if (opt->opt.__data[iter] == IPOPT_NOP) {
+				iter++;
+			} else {
 				iter += opt->opt.__data[iter + 1];
 				optlen_new = iter;
-			} else
-				iter++;
+			}
+		}
 		hdr_delta = opt->opt.optlen;
 		opt->opt.optlen = (optlen_new + 3) & ~3;
 		hdr_delta -= opt->opt.optlen;