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author | Jann Horn <jannh@google.com> | 2023-11-22 22:44:47 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-12-03 07:33:07 +0100 |
commit | 2214e2bb5489145aba944874d0ee1652a0a63dc8 (patch) | |
tree | b97ad7537f91a4439e14519bb17aa7a6bad9f187 /net/tls | |
parent | fe5b55bcfe242fc4a02770a3f79ac76e28334271 (diff) | |
download | linux-stable-2214e2bb5489145aba944874d0ee1652a0a63dc8.tar.gz linux-stable-2214e2bb5489145aba944874d0ee1652a0a63dc8.tar.bz2 linux-stable-2214e2bb5489145aba944874d0ee1652a0a63dc8.zip |
tls: fix NULL deref on tls_sw_splice_eof() with empty record
commit 53f2cb491b500897a619ff6abd72f565933760f0 upstream.
syzkaller discovered that if tls_sw_splice_eof() is executed as part of
sendfile() when the plaintext/ciphertext sk_msg are empty, the send path
gets confused because the empty ciphertext buffer does not have enough
space for the encryption overhead. This causes tls_push_record() to go on
the `split = true` path (which is only supposed to be used when interacting
with an attached BPF program), and then get further confused and hit the
tls_merge_open_record() path, which then assumes that there must be at
least one populated buffer element, leading to a NULL deref.
It is possible to have empty plaintext/ciphertext buffers if we previously
bailed from tls_sw_sendmsg_locked() via the tls_trim_both_msgs() path.
tls_sw_push_pending_record() already handles this case correctly; let's do
the same check in tls_sw_splice_eof().
Fixes: df720d288dbb ("tls/sw: Use splice_eof() to flush")
Cc: stable@vger.kernel.org
Reported-by: syzbot+40d43509a099ea756317@syzkaller.appspotmail.com
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/r/20231122214447.675768-1-jannh@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/tls')
-rw-r--r-- | net/tls/tls_sw.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index 9634dfd636fd..779815b885e9 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -1232,11 +1232,14 @@ void tls_sw_splice_eof(struct socket *sock) lock_sock(sk); retry: + /* same checks as in tls_sw_push_pending_record() */ rec = ctx->open_rec; if (!rec) goto unlock; msg_pl = &rec->msg_plaintext; + if (msg_pl->sg.size == 0) + goto unlock; /* Check the BPF advisor and perform transmission. */ ret = bpf_exec_tx_verdict(msg_pl, sk, false, TLS_RECORD_TYPE_DATA, |