Commit 7bca91d63341 for kernel

commit 7bca91d63341274e857f4aeaad54d229405e93dc
Author: chanyoung <ppoo1220@gmail.com>
Date:   Tue Aug 4 14:28:35 2026 +0900

    tls: don't leave a full plaintext sk_msg ring unpushed

    When the copy path in tls_sw_sendmsg_locked() adds the fragment that fills
    the plaintext sk_msg ring, it does not set full_record, so the record is
    left full and unpushed.  A later splice() then adds to an already full
    ring: sk_msg_page_add() has no fullness check of its own, so sg.end wraps
    onto sg.start and the ring appears empty.  Fragments added after that
    overwrite live entries, and sg.size no longer matches what is reachable
    between sg.start and sg.end, so pushing the record runs the scatterwalk off
    the end of the scatterlist.

    An unprivileged user can trigger this on a loopback TCP socket with the
    "tls" ULP attached:

      BUG: kernel NULL pointer dereference, address: 0000000000000008
      RIP: 0010:memcpy_from_scatterwalk+0x32/0xc0
      Call Trace:
       skcipher_walk_next+0x1d1/0x2c0
       gcm_encrypt_aesni_avx+0x1e9/0x220
       bpf_exec_tx_verdict+0x3bb/0x860
       tls_sw_sendmsg+0xa1a/0xca0
       __sys_sendto+0x1da/0x1f0

    Set full_record in the copy path when the ring becomes full, and push a
    record that is already full on entry to the sendmsg loop.

    Suggested-by: Sabrina Dubroca <sd@queasysnail.net>
    Fixes: fe1e81d4f73b ("tls/sw: Support MSG_SPLICE_PAGES")
    Cc: stable@vger.kernel.org
    Signed-off-by: chanyoung <ppoo1220@gmail.com>
    Link: https://patch.msgid.link/20260804052837.49015-2-ppoo1220@gmail.com
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index d4afc90fd796..d2e399be8ef6 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -832,6 +832,14 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
 		if (!sk_stream_memory_free(sk))
 			goto wait_for_sndbuf;

+		/* open record may be full if we couldn't push it in the last sendmsg call */
+		if (sk_msg_full(msg_pl)) {
+			full_record = true;
+			sk_msg_trim(sk, msg_en,
+				    msg_pl->sg.size + prot->overhead_size);
+			goto copied;
+		}
+
 alloc_encrypted:
 		ret = tls_alloc_encrypted_msg(sk, required_size);
 		if (ret) {
@@ -921,6 +929,12 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
 						       msg_pl, try_to_copy);
 			if (ret < 0)
 				goto trim_sgl;
+
+			if (sk_msg_full(msg_pl)) {
+				full_record = true;
+				sk_msg_trim(sk, msg_en,
+					    msg_pl->sg.size + prot->overhead_size);
+			}
 		}

 		/* Open records defined only if successfully copied, otherwise