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KASAN detects a null-ptr-deref when eBPF tracing fentry/fexit programs are attached to points such as __mmap_region and file_map_prot_check kernel functions. This can result in a NULL file pointer flowing from context to the helper. A minimal check before dereferencing can fix this. Fixes: b60da4955f53 ("bpf: Only provide bpf_sock_from_file with CONFIG_NET") Reviewed-by: Emil Tsalapatis Signed-off-by: Syeda Mahnur Asif --- v2: - Added Reviewed-by from Emil Tsalapatis - Fixed name in Signed-off-by net/core/filter.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/core/filter.c b/net/core/filter.c index 16845987b244..7c3caae4bafc 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -12182,7 +12182,10 @@ const struct bpf_func_proto bpf_skc_to_mptcp_sock_proto = { BPF_CALL_1(bpf_sock_from_file, struct file *, file) { - return (unsigned long)sock_from_file(file); + if (file) + return (unsigned long)sock_from_file(file); + + return (unsigned long)NULL; } BTF_ID_LIST(bpf_sock_from_file_btf_ids) -- 2.53.0