From 5696fee4c69fe3cc12e8cc821630633f616db8e2 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Thu, 23 Jul 2026 18:38:59 +0000 Subject: [PATCH] add print_hexstring helper hexstring_n2a() writes into a caller-supplied buffer and silently truncates when it is too small: the loop stops once fewer than three bytes remain and returns the partial string. Callers using a fixed SPRINT_BUF therefore drop trailing bytes for keys wider than 31 bytes. Add a new function print_hexstring() that formats and prints a binary attribute in one call. Convert the callers that dump a binary attribute straight to output over to print_hexstring(). Signed-off-by: Stephen Hemminger Reported-by: Gris Ge --- include/json_print.h | 3 +++ ip/ipaddress.c | 19 ++++++------------- ip/ipmacsec.c | 7 ++----- lib/bpf_legacy.c | 6 ++---- lib/json_print.c | 13 +++++++++++++ tc/f_bpf.c | 8 +++----- tc/m_action.c | 9 +++------ tc/m_bpf.c | 9 +++------ 8 files changed, 35 insertions(+), 39 deletions(-) diff --git a/include/json_print.h b/include/json_print.h index c0d6315f1..6a4581891 100644 --- a/include/json_print.h +++ b/include/json_print.h @@ -84,6 +84,9 @@ _PRINT_FUNC(float, double) _PRINT_FUNC(tv, const struct timeval *) #undef _PRINT_FUNC +void print_hexstring(const char *key, const char *fmt, + const __u8 *data, unsigned int len); + #define _PRINT_NAME_VALUE_FUNC(type_name, type, format_char) \ void print_##type_name##_name_value(const char *name, type value) \ diff --git a/ip/ipaddress.c b/ip/ipaddress.c index 6017bc837..7e4cb77c4 100644 --- a/ip/ipaddress.c +++ b/ip/ipaddress.c @@ -1263,22 +1263,15 @@ int print_linkinfo(struct nlmsghdr *n, void *arg) rta_getattr_str(tb[IFLA_PHYS_PORT_NAME])); if (tb[IFLA_PHYS_PORT_ID]) { - print_string(PRINT_ANY, - "phys_port_id", - "portid %s ", - hexstring_n2a( - RTA_DATA(tb[IFLA_PHYS_PORT_ID]), - RTA_PAYLOAD(tb[IFLA_PHYS_PORT_ID]), - b1, sizeof(b1))); + print_hexstring("phys_port_id", "portid %s ", + RTA_DATA(tb[IFLA_PHYS_PORT_ID]), + RTA_PAYLOAD(tb[IFLA_PHYS_PORT_ID])); } if (tb[IFLA_PHYS_SWITCH_ID]) { - print_string(PRINT_ANY, - "phys_switch_id", - "switchid %s ", - hexstring_n2a(RTA_DATA(tb[IFLA_PHYS_SWITCH_ID]), - RTA_PAYLOAD(tb[IFLA_PHYS_SWITCH_ID]), - b1, sizeof(b1))); + print_hexstring("phys_switch_id", "switchid %s ", + RTA_DATA(tb[IFLA_PHYS_SWITCH_ID]), + RTA_PAYLOAD(tb[IFLA_PHYS_SWITCH_ID])); } if (tb[IFLA_PARENT_DEV_BUS_NAME]) { diff --git a/ip/ipmacsec.c b/ip/ipmacsec.c index fc4c86314..1864ffd3c 100644 --- a/ip/ipmacsec.c +++ b/ip/ipmacsec.c @@ -661,11 +661,8 @@ static void print_flag(struct rtattr *attrs[], const char *desc, static void print_key(struct rtattr *key) { - SPRINT_BUF(keyid); - - print_string(PRINT_ANY, "key", " key %s\n", - hexstring_n2a(RTA_DATA(key), RTA_PAYLOAD(key), - keyid, sizeof(keyid))); + print_hexstring("key", " key %s\n", + RTA_DATA(key), RTA_PAYLOAD(key)); } #define CIPHER_NAME_GCM_AES_128 "GCM-AES-128" diff --git a/lib/bpf_legacy.c b/lib/bpf_legacy.c index 50ca82c1a..9d5fcf5f5 100644 --- a/lib/bpf_legacy.c +++ b/lib/bpf_legacy.c @@ -176,7 +176,6 @@ int bpf_dump_prog_info(FILE *f, uint32_t id) struct bpf_prog_info info = {}; uint32_t len = sizeof(info); int fd, ret, dump_ok = 0; - SPRINT_BUF(tmp); open_json_object("prog"); print_uint(PRINT_ANY, "id", "id %u ", id); @@ -190,9 +189,8 @@ int bpf_dump_prog_info(FILE *f, uint32_t id) int jited = !!info.jited_prog_len; print_string(PRINT_ANY, "name", "name %s ", info.name); - print_string(PRINT_ANY, "tag", "tag %s ", - hexstring_n2a(info.tag, sizeof(info.tag), - tmp, sizeof(tmp))); + print_hexstring("tag", "tag %s ", + info.tag, sizeof(info.tag)); print_uint(PRINT_JSON, "jited", NULL, jited); if (jited && !is_json_context()) fprintf(f, "jited "); diff --git a/lib/json_print.c b/lib/json_print.c index 810d496e9..f604f2652 100644 --- a/lib/json_print.c +++ b/lib/json_print.c @@ -179,6 +179,19 @@ int print_color_string(enum output_type type, return ret; } +/* Print binary data as a hex string. The buffer is sized to the input, + * so keys of any length are printed in full rather than truncated. + */ +void print_hexstring(const char *key, const char *fmt, + const __u8 *data, unsigned int len) +{ + int blen = 2 * len + 1; + char buf[blen]; + + print_string(PRINT_ANY, key, fmt, + hexstring_n2a(data, len, buf, blen)); +} + /* * value's type is bool. When using this function in FP context you can't pass * a value to it, you will need to use "is_json_context()" to have different diff --git a/tc/f_bpf.c b/tc/f_bpf.c index 6dd75445c..50fe01cae 100644 --- a/tc/f_bpf.c +++ b/tc/f_bpf.c @@ -241,11 +241,9 @@ static int bpf_print_opt(const struct filter_util *qu, FILE *f, if (tb[TCA_BPF_ID]) dump_ok = bpf_dump_prog_info(f, rta_getattr_u32(tb[TCA_BPF_ID])); if (!dump_ok && tb[TCA_BPF_TAG]) { - SPRINT_BUF(b); - - print_string(PRINT_ANY, "tag", "tag %s ", - hexstring_n2a(RTA_DATA(tb[TCA_BPF_TAG]), - RTA_PAYLOAD(tb[TCA_BPF_TAG]), b, sizeof(b))); + print_hexstring("tag", "tag %s ", + RTA_DATA(tb[TCA_BPF_TAG]), + RTA_PAYLOAD(tb[TCA_BPF_TAG])); } if (tb[TCA_BPF_POLICE]) { diff --git a/tc/m_action.c b/tc/m_action.c index 6f79fdae7..bbc8e6a68 100644 --- a/tc/m_action.c +++ b/tc/m_action.c @@ -401,12 +401,9 @@ static int tc_print_one_action(FILE *f, struct rtattr *arg, bool bind) print_nl(); } if (tb[TCA_ACT_COOKIE]) { - int strsz = RTA_PAYLOAD(tb[TCA_ACT_COOKIE]); - char b1[strsz * 2 + 1]; - - print_string(PRINT_ANY, "cookie", "\tcookie %s", - hexstring_n2a(RTA_DATA(tb[TCA_ACT_COOKIE]), - strsz, b1, sizeof(b1))); + print_hexstring("cookie", "\tcookie %s", + RTA_DATA(tb[TCA_ACT_COOKIE]), + RTA_PAYLOAD(tb[TCA_ACT_COOKIE])); print_nl(); } if (tb[TCA_ACT_FLAGS] || tb[TCA_ACT_IN_HW_COUNT]) { diff --git a/tc/m_bpf.c b/tc/m_bpf.c index a5de7da1f..83b21b57b 100644 --- a/tc/m_bpf.c +++ b/tc/m_bpf.c @@ -183,12 +183,9 @@ static int bpf_print_opt(const struct action_util *au, FILE *f, struct rtattr *a d_ok = bpf_dump_prog_info(f, rta_getattr_u32(tb[TCA_ACT_BPF_ID])); if (!d_ok && tb[TCA_ACT_BPF_TAG]) { - SPRINT_BUF(b); - - print_string(PRINT_ANY, "tag", "tag %s ", - hexstring_n2a(RTA_DATA(tb[TCA_ACT_BPF_TAG]), - RTA_PAYLOAD(tb[TCA_ACT_BPF_TAG]), - b, sizeof(b))); + print_hexstring("tag", "tag %s ", + RTA_DATA(tb[TCA_ACT_BPF_TAG]), + RTA_PAYLOAD(tb[TCA_ACT_BPF_TAG])); } print_action_control("default-action ", parm->action, _SL_); -- 2.47.3