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authorStanislav Fomichev <sdf@google.com>2019-07-01 10:38:39 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2019-07-08 16:22:55 +0200
commit600c70bad6594cb124c641ed05355ca134650ea4 (patch)
tree64b117309f808caca760fc11a37284880654eda3 /net/core
parentd2850ce0bdd772a85043b1f07af99205b96e6e2a (diff)
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bpf: allow wide (u64) aligned stores for some fields of bpf_sock_addr
Since commit cd17d7770578 ("bpf/tools: sync bpf.h") clang decided that it can do a single u64 store into user_ip6[2] instead of two separate u32 ones: # 17: (18) r2 = 0x100000000000000 # ; ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2); # 19: (7b) *(u64 *)(r1 +16) = r2 # invalid bpf_context access off=16 size=8 >From the compiler point of view it does look like a correct thing to do, so let's support it on the kernel side. Credit to Andrii Nakryiko for a proper implementation of bpf_ctx_wide_store_ok. Cc: Andrii Nakryiko <andriin@fb.com> Cc: Yonghong Song <yhs@fb.com> Fixes: cd17d7770578 ("bpf/tools: sync bpf.h") Reported-by: kernel test robot <rong.a.chen@intel.com> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/filter.c22
1 files changed, 14 insertions, 8 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 089aaea0ccc6..4481e950f020 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6890,6 +6890,16 @@ static bool sock_addr_is_valid_access(int off, int size,
if (!bpf_ctx_narrow_access_ok(off, size, size_default))
return false;
} else {
+ if (bpf_ctx_wide_store_ok(off, size,
+ struct bpf_sock_addr,
+ user_ip6))
+ return true;
+
+ if (bpf_ctx_wide_store_ok(off, size,
+ struct bpf_sock_addr,
+ msg_src_ip6))
+ return true;
+
if (size != size_default)
return false;
}
@@ -7730,9 +7740,6 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type,
/* SOCK_ADDR_STORE_NESTED_FIELD_OFF() has semantic similar to
* SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF() but for store operation.
*
- * It doesn't support SIZE argument though since narrow stores are not
- * supported for now.
- *
* In addition it uses Temporary Field TF (member of struct S) as the 3rd
* "register" since two registers available in convert_ctx_access are not
* enough: we can't override neither SRC, since it contains value to store, nor
@@ -7740,7 +7747,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type,
* instructions. But we need a temporary place to save pointer to nested
* structure whose field we want to store to.
*/
-#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, TF) \
+#define SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, OFF, TF) \
do { \
int tmp_reg = BPF_REG_9; \
if (si->src_reg == tmp_reg || si->dst_reg == tmp_reg) \
@@ -7751,8 +7758,7 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type,
offsetof(S, TF)); \
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(S, F), tmp_reg, \
si->dst_reg, offsetof(S, F)); \
- *insn++ = BPF_STX_MEM( \
- BPF_FIELD_SIZEOF(NS, NF), tmp_reg, si->src_reg, \
+ *insn++ = BPF_STX_MEM(SIZE, tmp_reg, si->src_reg, \
bpf_target_off(NS, NF, FIELD_SIZEOF(NS, NF), \
target_size) \
+ OFF); \
@@ -7764,8 +7770,8 @@ static u32 xdp_convert_ctx_access(enum bpf_access_type type,
TF) \
do { \
if (type == BPF_WRITE) { \
- SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, OFF, \
- TF); \
+ SOCK_ADDR_STORE_NESTED_FIELD_OFF(S, NS, F, NF, SIZE, \
+ OFF, TF); \
} else { \
SOCK_ADDR_LOAD_NESTED_FIELD_SIZE_OFF( \
S, NS, F, NF, SIZE, OFF); \