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| author | Aleksandr Mishin <amishin@t-argos.ru> | 2024-08-27 10:48:22 +0200 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2024-08-29 12:08:44 +0200 |
| commit | febccb39255f9df35527b88c953b2e0deae50e53 (patch) | |
| tree | 4d183d96abafffbda47a26fc0f2c0eebf342e371 | |
| parent | Merge tag 'nf-24-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/netf... (diff) | |
| download | linux-febccb39255f9df35527b88c953b2e0deae50e53.tar.xz linux-febccb39255f9df35527b88c953b2e0deae50e53.zip | |
nfc: pn533: Add poll mod list filling check
In case of im_protocols value is 1 and tm_protocols value is 0 this
combination successfully passes the check
'if (!im_protocols && !tm_protocols)' in the nfc_start_poll().
But then after pn533_poll_create_mod_list() call in pn533_start_poll()
poll mod list will remain empty and dev->poll_mod_count will remain 0
which lead to division by zero.
Normally no im protocol has value 1 in the mask, so this combination is
not expected by driver. But these protocol values actually come from
userspace via Netlink interface (NFC_CMD_START_POLL operation). So a
broken or malicious program may pass a message containing a "bad"
combination of protocol parameter values so that dev->poll_mod_count
is not incremented inside pn533_poll_create_mod_list(), thus leading
to division by zero.
Call trace looks like:
nfc_genl_start_poll()
nfc_start_poll()
->start_poll()
pn533_start_poll()
Add poll mod list filling check.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: dfccd0f58044 ("NFC: pn533: Add some polling entropy")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20240827084822.18785-1-amishin@t-argos.ru
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
| -rw-r--r-- | drivers/nfc/pn533/pn533.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/nfc/pn533/pn533.c b/drivers/nfc/pn533/pn533.c index b19c39dcfbd9..e2bc67300a91 100644 --- a/drivers/nfc/pn533/pn533.c +++ b/drivers/nfc/pn533/pn533.c @@ -1723,6 +1723,11 @@ static int pn533_start_poll(struct nfc_dev *nfc_dev, } pn533_poll_create_mod_list(dev, im_protocols, tm_protocols); + if (!dev->poll_mod_count) { + nfc_err(dev->dev, + "Poll mod list is empty\n"); + return -EINVAL; + } /* Do not always start polling from the same modulation */ get_random_bytes(&rand_mod, sizeof(rand_mod)); |