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-rw-r--r--include/linux/filter.h16
-rw-r--r--kernel/bpf/verifier.c21
-rw-r--r--tools/testing/selftests/bpf/test_sock_addr.c28
-rw-r--r--tools/testing/selftests/bpf/test_verifier.c48
4 files changed, 79 insertions, 34 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h
index de629b706d1d..cc17f5f32fbb 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -668,24 +668,10 @@ static inline u32 bpf_ctx_off_adjust_machine(u32 size)
return size;
}
-static inline bool bpf_ctx_narrow_align_ok(u32 off, u32 size_access,
- u32 size_default)
-{
- size_default = bpf_ctx_off_adjust_machine(size_default);
- size_access = bpf_ctx_off_adjust_machine(size_access);
-
-#ifdef __LITTLE_ENDIAN
- return (off & (size_default - 1)) == 0;
-#else
- return (off & (size_default - 1)) + size_access == size_default;
-#endif
-}
-
static inline bool
bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default)
{
- return bpf_ctx_narrow_align_ok(off, size, size_default) &&
- size <= size_default && (size & (size - 1)) == 0;
+ return size <= size_default && (size & (size - 1)) == 0;
}
#define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 8d0977980cfa..b5222aa61d54 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5718,10 +5718,10 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
int i, cnt, size, ctx_field_size, delta = 0;
const int insn_cnt = env->prog->len;
struct bpf_insn insn_buf[16], *insn;
+ u32 target_size, size_default, off;
struct bpf_prog *new_prog;
enum bpf_access_type type;
bool is_narrower_load;
- u32 target_size;
if (ops->gen_prologue || env->seen_direct_write) {
if (!ops->gen_prologue) {
@@ -5814,9 +5814,9 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
* we will apply proper mask to the result.
*/
is_narrower_load = size < ctx_field_size;
+ size_default = bpf_ctx_off_adjust_machine(ctx_field_size);
+ off = insn->off;
if (is_narrower_load) {
- u32 size_default = bpf_ctx_off_adjust_machine(ctx_field_size);
- u32 off = insn->off;
u8 size_code;
if (type == BPF_WRITE) {
@@ -5844,12 +5844,23 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
}
if (is_narrower_load && size < target_size) {
- if (ctx_field_size <= 4)
+ u8 shift = (off & (size_default - 1)) * 8;
+
+ if (ctx_field_size <= 4) {
+ if (shift)
+ insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH,
+ insn->dst_reg,
+ shift);
insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
(1 << size * 8) - 1);
- else
+ } else {
+ if (shift)
+ insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH,
+ insn->dst_reg,
+ shift);
insn_buf[cnt++] = BPF_ALU64_IMM(BPF_AND, insn->dst_reg,
(1 << size * 8) - 1);
+ }
}
new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
diff --git a/tools/testing/selftests/bpf/test_sock_addr.c b/tools/testing/selftests/bpf/test_sock_addr.c
index aeeb76a54d63..73b7493d4120 100644
--- a/tools/testing/selftests/bpf/test_sock_addr.c
+++ b/tools/testing/selftests/bpf/test_sock_addr.c
@@ -574,24 +574,44 @@ static int bind4_prog_load(const struct sock_addr_test *test)
/* if (sk.family == AF_INET && */
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, family)),
- BPF_JMP_IMM(BPF_JNE, BPF_REG_7, AF_INET, 16),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_7, AF_INET, 24),
/* (sk.type == SOCK_DGRAM || sk.type == SOCK_STREAM) && */
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, type)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_7, SOCK_DGRAM, 1),
BPF_JMP_A(1),
- BPF_JMP_IMM(BPF_JNE, BPF_REG_7, SOCK_STREAM, 12),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_7, SOCK_STREAM, 20),
/* 1st_byte_of_user_ip4 == expected && */
BPF_LDX_MEM(BPF_B, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, user_ip4)),
- BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip4.u4_addr8[0], 10),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip4.u4_addr8[0], 18),
+
+ /* 2nd_byte_of_user_ip4 == expected && */
+ BPF_LDX_MEM(BPF_B, BPF_REG_7, BPF_REG_6,
+ offsetof(struct bpf_sock_addr, user_ip4) + 1),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip4.u4_addr8[1], 16),
+
+ /* 3rd_byte_of_user_ip4 == expected && */
+ BPF_LDX_MEM(BPF_B, BPF_REG_7, BPF_REG_6,
+ offsetof(struct bpf_sock_addr, user_ip4) + 2),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip4.u4_addr8[2], 14),
+
+ /* 4th_byte_of_user_ip4 == expected && */
+ BPF_LDX_MEM(BPF_B, BPF_REG_7, BPF_REG_6,
+ offsetof(struct bpf_sock_addr, user_ip4) + 3),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip4.u4_addr8[3], 12),
/* 1st_half_of_user_ip4 == expected && */
BPF_LDX_MEM(BPF_H, BPF_REG_7, BPF_REG_6,
offsetof(struct bpf_sock_addr, user_ip4)),
- BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip4.u4_addr16[0], 8),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip4.u4_addr16[0], 10),
+
+ /* 2nd_half_of_user_ip4 == expected && */
+ BPF_LDX_MEM(BPF_H, BPF_REG_7, BPF_REG_6,
+ offsetof(struct bpf_sock_addr, user_ip4) + 2),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_7, ip4.u4_addr16[1], 8),
/* whole_user_ip4 == expected) { */
BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 6f61df62f690..54d16fbdef8b 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -2026,29 +2026,27 @@ static struct bpf_test tests[] = {
.result = ACCEPT,
},
{
- "check skb->hash byte load not permitted 1",
+ "check skb->hash byte load permitted 1",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash) + 1),
BPF_EXIT_INSN(),
},
- .errstr = "invalid bpf_context access",
- .result = REJECT,
+ .result = ACCEPT,
},
{
- "check skb->hash byte load not permitted 2",
+ "check skb->hash byte load permitted 2",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
offsetof(struct __sk_buff, hash) + 2),
BPF_EXIT_INSN(),
},
- .errstr = "invalid bpf_context access",
- .result = REJECT,
+ .result = ACCEPT,
},
{
- "check skb->hash byte load not permitted 3",
+ "check skb->hash byte load permitted 3",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
#if __BYTE_ORDER == __LITTLE_ENDIAN
@@ -2060,8 +2058,7 @@ static struct bpf_test tests[] = {
#endif
BPF_EXIT_INSN(),
},
- .errstr = "invalid bpf_context access",
- .result = REJECT,
+ .result = ACCEPT,
},
{
"check cb access: byte, wrong type",
@@ -2173,7 +2170,7 @@ static struct bpf_test tests[] = {
.result = ACCEPT,
},
{
- "check skb->hash half load not permitted",
+ "check skb->hash half load permitted 2",
.insns = {
BPF_MOV64_IMM(BPF_REG_0, 0),
#if __BYTE_ORDER == __LITTLE_ENDIAN
@@ -2185,6 +2182,37 @@ static struct bpf_test tests[] = {
#endif
BPF_EXIT_INSN(),
},
+ .result = ACCEPT,
+ },
+ {
+ "check skb->hash half load not permitted, unaligned 1",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+ BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+ offsetof(struct __sk_buff, hash) + 1),
+#else
+ BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+ offsetof(struct __sk_buff, hash) + 3),
+#endif
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ },
+ {
+ "check skb->hash half load not permitted, unaligned 3",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+ BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+ offsetof(struct __sk_buff, hash) + 3),
+#else
+ BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+ offsetof(struct __sk_buff, hash) + 1),
+#endif
+ BPF_EXIT_INSN(),
+ },
.errstr = "invalid bpf_context access",
.result = REJECT,
},
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.