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authorAlexei Starovoitov <ast@fb.com>2016-06-15 18:25:38 -0700
committerDavid S. Miller <davem@davemloft.net>2016-06-15 23:37:54 -0700
commit19de99f70b87fcc3338da52a89c439b088cbff71 (patch)
tree43b5ff80043ee9ea62e09fe568502c9d68a188ee /net
parente582615ad33dbd39623084a02e95567b116e1eea (diff)
downloadlinux-19de99f70b87fcc3338da52a89c439b088cbff71.tar.gz
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')
-rw-r--r--net/core/filter.c16
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);
}