diff options
| -rw-r--r-- | net/core/filter.c | 36 |
1 files changed, 22 insertions, 14 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index a6bb95fa87b26..946f758d44f2f 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -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 @@ do_pass: 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 @@ do_pass: /* 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 @@ do_pass: 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, |