diff --git a/include/linux/bpf.h b/include/linux/bpf.h index fd06ada941ad..f15432d90728 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -989,6 +989,8 @@ extern const struct bpf_func_proto bpf_sk_redirect_map_proto; extern const struct bpf_func_proto bpf_spin_lock_proto; extern const struct bpf_func_proto bpf_spin_unlock_proto; extern const struct bpf_func_proto bpf_get_local_storage_proto; +extern const struct bpf_func_proto bpf_strtol_proto; +extern const struct bpf_func_proto bpf_strtoul_proto; /* Shared helpers among cBPF and eBPF. */ void bpf_user_rnd_init_once(void); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 89976de909af..c26be24fd5e2 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2575,6 +2575,53 @@ union bpf_attr { * **-E2BIG** if the *buf_len* is too big. * * **-EINVAL** if sysctl is being read. + * + * int bpf_strtol(const char *buf, size_t buf_len, u64 flags, long *res) + * Description + * Convert the initial part of the string from buffer *buf* of + * size *buf_len* to a long integer according to the given base + * and save the result in *res*. + * + * The string may begin with an arbitrary amount of white space + * (as determined by isspace(3)) followed by a single optional '-' + * sign. + * + * Five least significant bits of *flags* encode base, other bits + * are currently unused. + * + * Base must be either 8, 10, 16 or 0 to detect it automatically + * similar to user space strtol(3). + * Return + * Number of characters consumed on success. Must be positive but + * no more than buf_len. + * + * **-EINVAL** if no valid digits were found or unsupported base + * was provided. + * + * **-ERANGE** if resulting value was out of range. + * + * int bpf_strtoul(const char *buf, size_t buf_len, u64 flags, unsigned long *res) + * Description + * Convert the initial part of the string from buffer *buf* of + * size *buf_len* to an unsigned long integer according to the + * given base and save the result in *res*. + * + * The string may begin with an arbitrary amount of white space + * (as determined by isspace(3)). + * + * Five least significant bits of *flags* encode base, other bits + * are currently unused. + * + * Base must be either 8, 10, 16 or 0 to detect it automatically + * similar to user space strtoul(3). + * Return + * Number of characters consumed on success. Must be positive but + * no more than buf_len. + * + * **-EINVAL** if no valid digits were found or unsupported base + * was provided. + * + * **-ERANGE** if resulting value was out of range. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -2681,7 +2728,9 @@ union bpf_attr { FN(sysctl_get_name), \ FN(sysctl_get_current_value), \ FN(sysctl_get_new_value), \ - FN(sysctl_set_new_value), + FN(sysctl_set_new_value), \ + FN(strtol), \ + FN(strtoul), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index b2adf22139b3..789d4ab2336e 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -1016,6 +1016,10 @@ static const struct bpf_func_proto * sysctl_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { + case BPF_FUNC_strtol: + return &bpf_strtol_proto; + case BPF_FUNC_strtoul: + return &bpf_strtoul_proto; case BPF_FUNC_sysctl_get_name: return &bpf_sysctl_get_name_proto; case BPF_FUNC_sysctl_get_current_value: diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index a411fc17d265..4266ffde07ca 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -18,6 +18,9 @@ #include #include #include +#include + +#include "../../lib/kstrtox.h" /* If kernel subsystem is allowing eBPF programs to call this function, * inside its own verifier_ops->get_func_proto() callback it should return @@ -363,4 +366,132 @@ const struct bpf_func_proto bpf_get_local_storage_proto = { .arg2_type = ARG_ANYTHING, }; #endif + +#define BPF_STRTOX_BASE_MASK 0x1F + +static int __bpf_strtoull(const char *buf, size_t buf_len, u64 flags, + unsigned long long *res, bool *is_negative) +{ + unsigned int base = flags & BPF_STRTOX_BASE_MASK; + const char *cur_buf = buf; + size_t cur_len = buf_len; + unsigned int consumed; + size_t val_len; + char str[64]; + + if (!buf || !buf_len || !res || !is_negative) + return -EINVAL; + + if (base != 0 && base != 8 && base != 10 && base != 16) + return -EINVAL; + + if (flags & ~BPF_STRTOX_BASE_MASK) + return -EINVAL; + + while (cur_buf < buf + buf_len && isspace(*cur_buf)) + ++cur_buf; + + *is_negative = (cur_buf < buf + buf_len && *cur_buf == '-'); + if (*is_negative) + ++cur_buf; + + consumed = cur_buf - buf; + cur_len -= consumed; + if (!cur_len) + return -EINVAL; + + cur_len = min(cur_len, sizeof(str) - 1); + memcpy(str, cur_buf, cur_len); + str[cur_len] = '\0'; + cur_buf = str; + + cur_buf = _parse_integer_fixup_radix(cur_buf, &base); + val_len = _parse_integer(cur_buf, base, res); + + if (val_len & KSTRTOX_OVERFLOW) + return -ERANGE; + + if (val_len == 0) + return -EINVAL; + + cur_buf += val_len; + consumed += cur_buf - str; + + return consumed; +} + +static int __bpf_strtoll(const char *buf, size_t buf_len, u64 flags, + long long *res) +{ + unsigned long long _res; + bool is_negative; + int err; + + err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative); + if (err < 0) + return err; + if (is_negative) { + if ((long long)-_res > 0) + return -ERANGE; + *res = -_res; + } else { + if ((long long)_res < 0) + return -ERANGE; + *res = _res; + } + return err; +} + +BPF_CALL_4(bpf_strtol, const char *, buf, size_t, buf_len, u64, flags, + long *, res) +{ + long long _res; + int err; + + err = __bpf_strtoll(buf, buf_len, flags, &_res); + if (err < 0) + return err; + if (_res != (long)_res) + return -ERANGE; + *res = _res; + return err; +} + +const struct bpf_func_proto bpf_strtol_proto = { + .func = bpf_strtol, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_MEM, + .arg2_type = ARG_CONST_SIZE, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_PTR_TO_LONG, +}; + +BPF_CALL_4(bpf_strtoul, const char *, buf, size_t, buf_len, u64, flags, + unsigned long *, res) +{ + unsigned long long _res; + bool is_negative; + int err; + + err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative); + if (err < 0) + return err; + if (is_negative) + return -EINVAL; + if (_res != (unsigned long)_res) + return -ERANGE; + *res = _res; + return err; +} + +const struct bpf_func_proto bpf_strtoul_proto = { + .func = bpf_strtoul, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_MEM, + .arg2_type = ARG_CONST_SIZE, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_PTR_TO_LONG, +}; #endif