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bpf: prepare reg_set_min_max for second set of registers
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Similarly to is_branch_taken()-related refactorings, start preparing
reg_set_min_max() to handle more generic case of two non-const
registers. Start with renaming arguments to accommodate later addition
of second register as an input argument.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231102033759.2541186-17-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored and Alexei Starovoitov committed Nov 10, 2023
1 parent 4d34588 commit 811476e
Showing 1 changed file with 40 additions and 40 deletions.
80 changes: 40 additions & 40 deletions kernel/bpf/verifier.c
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Original file line number Diff line number Diff line change
Expand Up @@ -14405,25 +14405,25 @@ static int is_branch_taken(struct bpf_reg_state *reg1, struct bpf_reg_state *reg
* simply doing a BPF_K check.
* In JEQ/JNE cases we also adjust the var_off values.
*/
static void reg_set_min_max(struct bpf_reg_state *true_reg,
struct bpf_reg_state *false_reg,
static void reg_set_min_max(struct bpf_reg_state *true_reg1,
struct bpf_reg_state *false_reg1,
u64 uval, u32 uval32,
u8 opcode, bool is_jmp32)
{
struct tnum false_32off = tnum_subreg(false_reg->var_off);
struct tnum false_64off = false_reg->var_off;
struct tnum true_32off = tnum_subreg(true_reg->var_off);
struct tnum true_64off = true_reg->var_off;
struct tnum false_32off = tnum_subreg(false_reg1->var_off);
struct tnum false_64off = false_reg1->var_off;
struct tnum true_32off = tnum_subreg(true_reg1->var_off);
struct tnum true_64off = true_reg1->var_off;
s64 sval = (s64)uval;
s32 sval32 = (s32)uval32;

/* If the dst_reg is a pointer, we can't learn anything about its
* variable offset from the compare (unless src_reg were a pointer into
* the same object, but we don't bother with that.
* Since false_reg and true_reg have the same type by construction, we
* Since false_reg1 and true_reg1 have the same type by construction, we
* only need to check one of them for pointerness.
*/
if (__is_pointer_value(false, false_reg))
if (__is_pointer_value(false, false_reg1))
return;

switch (opcode) {
Expand All @@ -14438,20 +14438,20 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
*/
case BPF_JEQ:
if (is_jmp32) {
__mark_reg32_known(true_reg, uval32);
true_32off = tnum_subreg(true_reg->var_off);
__mark_reg32_known(true_reg1, uval32);
true_32off = tnum_subreg(true_reg1->var_off);
} else {
___mark_reg_known(true_reg, uval);
true_64off = true_reg->var_off;
___mark_reg_known(true_reg1, uval);
true_64off = true_reg1->var_off;
}
break;
case BPF_JNE:
if (is_jmp32) {
__mark_reg32_known(false_reg, uval32);
false_32off = tnum_subreg(false_reg->var_off);
__mark_reg32_known(false_reg1, uval32);
false_32off = tnum_subreg(false_reg1->var_off);
} else {
___mark_reg_known(false_reg, uval);
false_64off = false_reg->var_off;
___mark_reg_known(false_reg1, uval);
false_64off = false_reg1->var_off;
}
break;
case BPF_JSET:
Expand All @@ -14474,16 +14474,16 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
u32 false_umax = opcode == BPF_JGT ? uval32 : uval32 - 1;
u32 true_umin = opcode == BPF_JGT ? uval32 + 1 : uval32;

false_reg->u32_max_value = min(false_reg->u32_max_value,
false_reg1->u32_max_value = min(false_reg1->u32_max_value,
false_umax);
true_reg->u32_min_value = max(true_reg->u32_min_value,
true_reg1->u32_min_value = max(true_reg1->u32_min_value,
true_umin);
} else {
u64 false_umax = opcode == BPF_JGT ? uval : uval - 1;
u64 true_umin = opcode == BPF_JGT ? uval + 1 : uval;

false_reg->umax_value = min(false_reg->umax_value, false_umax);
true_reg->umin_value = max(true_reg->umin_value, true_umin);
false_reg1->umax_value = min(false_reg1->umax_value, false_umax);
true_reg1->umin_value = max(true_reg1->umin_value, true_umin);
}
break;
}
Expand All @@ -14494,14 +14494,14 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
s32 false_smax = opcode == BPF_JSGT ? sval32 : sval32 - 1;
s32 true_smin = opcode == BPF_JSGT ? sval32 + 1 : sval32;

false_reg->s32_max_value = min(false_reg->s32_max_value, false_smax);
true_reg->s32_min_value = max(true_reg->s32_min_value, true_smin);
false_reg1->s32_max_value = min(false_reg1->s32_max_value, false_smax);
true_reg1->s32_min_value = max(true_reg1->s32_min_value, true_smin);
} else {
s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1;
s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval;

false_reg->smax_value = min(false_reg->smax_value, false_smax);
true_reg->smin_value = max(true_reg->smin_value, true_smin);
false_reg1->smax_value = min(false_reg1->smax_value, false_smax);
true_reg1->smin_value = max(true_reg1->smin_value, true_smin);
}
break;
}
Expand All @@ -14512,16 +14512,16 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
u32 false_umin = opcode == BPF_JLT ? uval32 : uval32 + 1;
u32 true_umax = opcode == BPF_JLT ? uval32 - 1 : uval32;

false_reg->u32_min_value = max(false_reg->u32_min_value,
false_reg1->u32_min_value = max(false_reg1->u32_min_value,
false_umin);
true_reg->u32_max_value = min(true_reg->u32_max_value,
true_reg1->u32_max_value = min(true_reg1->u32_max_value,
true_umax);
} else {
u64 false_umin = opcode == BPF_JLT ? uval : uval + 1;
u64 true_umax = opcode == BPF_JLT ? uval - 1 : uval;

false_reg->umin_value = max(false_reg->umin_value, false_umin);
true_reg->umax_value = min(true_reg->umax_value, true_umax);
false_reg1->umin_value = max(false_reg1->umin_value, false_umin);
true_reg1->umax_value = min(true_reg1->umax_value, true_umax);
}
break;
}
Expand All @@ -14532,14 +14532,14 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
s32 false_smin = opcode == BPF_JSLT ? sval32 : sval32 + 1;
s32 true_smax = opcode == BPF_JSLT ? sval32 - 1 : sval32;

false_reg->s32_min_value = max(false_reg->s32_min_value, false_smin);
true_reg->s32_max_value = min(true_reg->s32_max_value, true_smax);
false_reg1->s32_min_value = max(false_reg1->s32_min_value, false_smin);
true_reg1->s32_max_value = min(true_reg1->s32_max_value, true_smax);
} else {
s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1;
s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval;

false_reg->smin_value = max(false_reg->smin_value, false_smin);
true_reg->smax_value = min(true_reg->smax_value, true_smax);
false_reg1->smin_value = max(false_reg1->smin_value, false_smin);
true_reg1->smax_value = min(true_reg1->smax_value, true_smax);
}
break;
}
Expand All @@ -14548,17 +14548,17 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
}

if (is_jmp32) {
false_reg->var_off = tnum_or(tnum_clear_subreg(false_64off),
false_reg1->var_off = tnum_or(tnum_clear_subreg(false_64off),
tnum_subreg(false_32off));
true_reg->var_off = tnum_or(tnum_clear_subreg(true_64off),
true_reg1->var_off = tnum_or(tnum_clear_subreg(true_64off),
tnum_subreg(true_32off));
reg_bounds_sync(false_reg);
reg_bounds_sync(true_reg);
reg_bounds_sync(false_reg1);
reg_bounds_sync(true_reg1);
} else {
false_reg->var_off = false_64off;
true_reg->var_off = true_64off;
reg_bounds_sync(false_reg);
reg_bounds_sync(true_reg);
false_reg1->var_off = false_64off;
true_reg1->var_off = true_64off;
reg_bounds_sync(false_reg1);
reg_bounds_sync(true_reg1);
}
}

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