nfc_llcp_wks_sap() passes service_name to pr_debug() using the %s format specifier. The service_name buffer is allocated via kmemdup() in llcp_sock_bind() and is not null-terminated, causing __dynamic_pr_debug() to read beyond the allocated region: KASAN: slab-out-of-bounds Read in __dynamic_pr_debug Fix by using %.*s with service_name_len to limit the output to the actual length of the string. Reported-by: syzbot+1e3df0852e82c21ca418@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=1e3df0852e82c21ca418 Signed-off-by: Ömer Mete Kaya --- net/nfc/llcp_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c index cac1b5487064..fda236e4d9fd 100644 --- a/net/nfc/llcp_core.c +++ b/net/nfc/llcp_core.c @@ -341,7 +341,7 @@ static int nfc_llcp_wks_sap(const char *service_name, size_t service_name_len) { int sap, num_wks; - pr_debug("%s\n", service_name); + pr_debug("%.*s\n", (int)service_name_len, service_name); if (service_name == NULL) return -EINVAL; -- 2.55.0