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authorDaniel Borkmann <daniel@iogearbox.net>2018-12-01 03:18:53 +0300
committerAlexei Starovoitov <ast@kernel.org>2018-12-01 04:04:35 +0300
commitb7df9ada9a7700dbcca1ba53d217c01e3d48179c (patch)
treeae0094e40a2e96aa1769113c1cbc6ba1c693fc04 /include/linux
parentc01ac66b38660f2b507ccd0b75d28e3002d56fbb (diff)
downloadlinux-b7df9ada9a7700dbcca1ba53d217c01e3d48179c.tar.xz
bpf: fix pointer offsets in context for 32 bit
Currently, pointer offsets in three BPF context structures are broken in two scenarios: i) 32 bit compiled applications running on 64 bit kernels, and ii) LLVM compiled BPF programs running on 32 bit kernels. The latter is due to BPF target machine being strictly 64 bit. So in each of the cases the offsets will mismatch in verifier when checking / rewriting context access. Fix this by providing a helper macro __bpf_md_ptr() that will enforce padding up to 64 bit and proper alignment, and for context access a macro bpf_ctx_range_ptr() which will cover full 64 bit member range on 32 bit archs. For flow_keys, we additionally need to force the size check to sizeof(__u64) as with other pointer types. Fixes: d58e468b1112 ("flow_dissector: implements flow dissector BPF hook") Fixes: 4f738adba30a ("bpf: create tcp_bpf_ulp allowing BPF to monitor socket TX/RX data") Fixes: 2dbb9b9e6df6 ("bpf: Introduce BPF_PROG_TYPE_SK_REUSEPORT") Reported-by: David S. Miller <davem@davemloft.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: David S. Miller <davem@davemloft.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/filter.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 448dcc448f1f..795ff0b869bb 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -449,6 +449,13 @@ struct sock_reuseport;
offsetof(TYPE, MEMBER) ... offsetofend(TYPE, MEMBER) - 1
#define bpf_ctx_range_till(TYPE, MEMBER1, MEMBER2) \
offsetof(TYPE, MEMBER1) ... offsetofend(TYPE, MEMBER2) - 1
+#if BITS_PER_LONG == 64
+# define bpf_ctx_range_ptr(TYPE, MEMBER) \
+ offsetof(TYPE, MEMBER) ... offsetofend(TYPE, MEMBER) - 1
+#else
+# define bpf_ctx_range_ptr(TYPE, MEMBER) \
+ offsetof(TYPE, MEMBER) ... offsetof(TYPE, MEMBER) + 8 - 1
+#endif /* BITS_PER_LONG == 64 */
#define bpf_target_off(TYPE, MEMBER, SIZE, PTR_SIZE) \
({ \