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authorBen Hutchings <ben.hutchings@codethink.co.uk>2018-12-05 22:45:15 +0000
committerMichael Bestas <mkbestas@lineageos.org>2022-04-19 00:51:26 +0300
commit2e201a9af1294e9061b2887af85905ea721b243c (patch)
tree0bc3de7167bb141447b66ed1f63150267b15e0ef
parent61ca638c1dfe77a3a461b479f21243875b9ae64a (diff)
bpf/verifier: Add spi variable to check_stack_write()
Extracted from commit dc503a8ad984 "bpf/verifier: track liveness for pruning". Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
-rw-r--r--kernel/bpf/verifier.c8
1 files changed, 3 insertions, 5 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index dafa2708ce9e..768704e9a2c7 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -543,7 +543,7 @@ static bool is_spillable_regtype(enum bpf_reg_type type)
static int check_stack_write(struct bpf_verifier_state *state, int off,
int size, int value_regno)
{
- int i;
+ int i, spi = (MAX_BPF_STACK + off) / BPF_REG_SIZE;
/* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
* so it's aligned access and [off, off + size) are within stack limits
*/
@@ -558,15 +558,13 @@ static int check_stack_write(struct bpf_verifier_state *state, int off,
}
/* save register state */
- state->spilled_regs[(MAX_BPF_STACK + off) / BPF_REG_SIZE] =
- state->regs[value_regno];
+ state->spilled_regs[spi] = state->regs[value_regno];
for (i = 0; i < BPF_REG_SIZE; i++)
state->stack_slot_type[MAX_BPF_STACK + off + i] = STACK_SPILL;
} else {
/* regular write of data into stack */
- state->spilled_regs[(MAX_BPF_STACK + off) / BPF_REG_SIZE] =
- (struct bpf_reg_state) {};
+ state->spilled_regs[spi] = (struct bpf_reg_state) {};
for (i = 0; i < size; i++)
state->stack_slot_type[MAX_BPF_STACK + off + i] = STACK_MISC;