53f2cb491b
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:
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|---|---|---|
| .. | ||
| Kconfig | ||
| Makefile | ||
| tls.h | ||
| tls_device.c | ||
| tls_device_fallback.c | ||
| tls_main.c | ||
| tls_proc.c | ||
| tls_strp.c | ||
| tls_sw.c | ||
| tls_toe.c | ||
| trace.c | ||
| trace.h | ||