diff options
| author | Alexei Starovoitov <ast@fb.com> | 2016-06-16 03:25:38 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-06-16 08:37:54 +0200 |
| commit | 19de99f70b87fcc3338da52a89c439b088cbff71 (patch) | |
| tree | 43b5ff80043ee9ea62e09fe568502c9d68a188ee /net/core | |
| parent | gre: fix error handler (diff) | |
| download | linux-19de99f70b87fcc3338da52a89c439b088cbff71.tar.xz linux-19de99f70b87fcc3338da52a89c439b088cbff71.zip | |
bpf: fix matching of data/data_end in verifier
The ctx structure passed into bpf programs is different depending on bpf
program type. The verifier incorrectly marked ctx->data and ctx->data_end
access based on ctx offset only. That caused loads in tracing programs
int bpf_prog(struct pt_regs *ctx) { .. ctx->ax .. }
to be incorrectly marked as PTR_TO_PACKET which later caused verifier
to reject the program that was actually valid in tracing context.
Fix this by doing program type specific matching of ctx offsets.
Fixes: 969bf05eb3ce ("bpf: direct packet access")
Reported-by: Sasha Goldshtein <goldshtn@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/filter.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index 68adb5f52110..c4b330c85c02 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2085,7 +2085,8 @@ static bool __is_valid_access(int off, int size, enum bpf_access_type type) } static bool sk_filter_is_valid_access(int off, int size, - enum bpf_access_type type) + enum bpf_access_type type, + enum bpf_reg_type *reg_type) { switch (off) { case offsetof(struct __sk_buff, tc_classid): @@ -2108,7 +2109,8 @@ static bool sk_filter_is_valid_access(int off, int size, } static bool tc_cls_act_is_valid_access(int off, int size, - enum bpf_access_type type) + enum bpf_access_type type, + enum bpf_reg_type *reg_type) { if (type == BPF_WRITE) { switch (off) { @@ -2123,6 +2125,16 @@ static bool tc_cls_act_is_valid_access(int off, int size, return false; } } + + switch (off) { + case offsetof(struct __sk_buff, data): + *reg_type = PTR_TO_PACKET; + break; + case offsetof(struct __sk_buff, data_end): + *reg_type = PTR_TO_PACKET_END; + break; + } + return __is_valid_access(off, size, type); } |