@@ -352,7 +352,7 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
* bpf_convert_filter - convert filter program
* @prog: the user passed filter program
* @len: the length of the user passed filter program
- * @new_prog: buffer where converted program will be stored
+ * @new_prog: allocated 'struct bpf_prog' or NULL
* @new_len: pointer to store length of converted program
*
* Remap 'sock_filter' style classic BPF (cBPF) instruction set to 'bpf_insn'
@@ -364,14 +364,13 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
*
* 2) 2nd pass to remap in two passes: 1st pass finds new
* jump offsets, 2nd pass remapping:
- * new_prog = kmalloc(sizeof(struct bpf_insn) * new_len);
* bpf_convert_filter(old_prog, old_len, new_prog, &new_len);
*/
static int bpf_convert_filter(struct sock_filter *prog, int len,
- struct bpf_insn *new_prog, int *new_len)
+ struct bpf_prog *new_prog, int *new_len)
{
- int new_flen = 0, pass = 0, target, i;
- struct bpf_insn *new_insn;
+ int new_flen = 0, pass = 0, target, i, stack_off;
+ struct bpf_insn *new_insn, *first_insn = NULL;
struct sock_filter *fp;
int *addrs = NULL;
u8 bpf_src;
@@ -383,6 +382,7 @@ static int bpf_convert_filter(struct sock_filter *prog, int len,
return -EINVAL;
if (new_prog) {
+ first_insn = new_prog->insnsi;
addrs = kcalloc(len, sizeof(*addrs),
GFP_KERNEL | __GFP_NOWARN);
if (!addrs)
@@ -390,11 +390,11 @@ static int bpf_convert_filter(struct sock_filter *prog, int len,
}
do_pass:
- new_insn = new_prog;
+ new_insn = first_insn;
fp = prog;
/* Classic BPF related prologue emission. */
- if (new_insn) {
+ if (new_prog) {
/* Classic BPF expects A and X to be reset first. These need
* to be guaranteed to be the first two instructions.
*/
@@ -415,7 +415,7 @@ static int bpf_convert_filter(struct sock_filter *prog, int len,
struct bpf_insn *insn = tmp_insns;
if (addrs)
- addrs[i] = new_insn - new_prog;
+ addrs[i] = new_insn - first_insn;
switch (fp->code) {
/* All arithmetic insns and skb loads map as-is. */
@@ -561,17 +561,25 @@ static int bpf_convert_filter(struct sock_filter *prog, int len,
/* Store to stack. */
case BPF_ST:
case BPF_STX:
+ stack_off = fp->k * 4 + 4;
*insn = BPF_STX_MEM(BPF_W, BPF_REG_FP, BPF_CLASS(fp->code) ==
BPF_ST ? BPF_REG_A : BPF_REG_X,
- -(BPF_MEMWORDS - fp->k) * 4);
+ -stack_off);
+ /* check_load_and_stores() verifies that classic BPF can
+ * load from stack only after write, so tracking
+ * stack_depth for ST|STX insns is enough
+ */
+ if (new_prog && new_prog->aux->stack_depth < stack_off)
+ new_prog->aux->stack_depth = stack_off;
break;
/* Load from stack. */
case BPF_LD | BPF_MEM:
case BPF_LDX | BPF_MEM:
+ stack_off = fp->k * 4 + 4;
*insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
BPF_REG_A : BPF_REG_X, BPF_REG_FP,
- -(BPF_MEMWORDS - fp->k) * 4);
+ -stack_off);
break;
/* A = K or X = K */
@@ -619,13 +627,13 @@ static int bpf_convert_filter(struct sock_filter *prog, int len,
if (!new_prog) {
/* Only calculating new length. */
- *new_len = new_insn - new_prog;
+ *new_len = new_insn - first_insn;
return 0;
}
pass++;
- if (new_flen != new_insn - new_prog) {
- new_flen = new_insn - new_prog;
+ if (new_flen != new_insn - first_insn) {
+ new_flen = new_insn - first_insn;
if (pass > 2)
goto err;
goto do_pass;
@@ -1017,7 +1025,7 @@ static struct bpf_prog *bpf_migrate_filter(struct bpf_prog *fp)
fp->len = new_len;
/* 2nd pass: remap sock_filter insns into bpf_insn insns. */
- err = bpf_convert_filter(old_prog, old_len, fp->insnsi, &new_len);
+ err = bpf_convert_filter(old_prog, old_len, fp, &new_len);
if (err)
/* 2nd bpf_convert_filter() can fail only if it fails
* to allocate memory, remapping must succeed. Note,