diff options
| author | Stefan Sperling <ssperling@sysmocom.de> | 2018-01-08 19:20:02 +0100 |
|---|---|---|
| committer | Harald Welte <laforge@gnumonks.org> | 2018-01-12 13:48:59 +0000 |
| commit | 1e50e2ad4813c037b0fbc5559381ec22776225d7 (patch) | |
| tree | 389ada1e65127e552ef730f6d216280826760a8d | |
| parent | ffad574a4b68596d17671965bf145f11f0b00e57 (diff) | |
TLVP_PRESENT() should not return TRUE after tlv_parse() fails.
If the length provided in the patcket exceeds the buffer length,
tlv_parse() returns -2 but leaves tlv.val and tlv.len initializd.
Many callers of tlv_parse() do not check its return value, but
rely on TLVP_PRESENT() to see if a particular TLV was parsed
successfully. By clearing tlv.val and tlv.len we make it less
likely that those callers will use an overlong TLV length value.
Change-Id: I4dda6938e1650b4bcaac45809a4763f86f5a9794
| -rw-r--r-- | src/gsm/tlv_parser.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/src/gsm/tlv_parser.c b/src/gsm/tlv_parser.c index ead856c9..9b1fb17a 100644 --- a/src/gsm/tlv_parser.c +++ b/src/gsm/tlv_parser.c @@ -127,7 +127,7 @@ int osmo_tlvp_merge(struct tlv_parsed *dst, const struct tlv_parsed *src) * \param[in] def structure defining the valid TLV tags / configurations * \param[in] buf the input data buffer to be parsed * \param[in] buf_len length of the input data buffer - * \returns number of bytes consumed by the TLV entry / IE parsed + * \returns number of bytes consumed by the TLV entry / IE parsed; negative in case of error */ int tlv_parse_one(uint8_t *o_tag, uint16_t *o_len, const uint8_t **o_val, const struct tlv_definition *def, @@ -227,7 +227,7 @@ tlv: /* GSM TS 04.07 11.2.4: Type 4 TLV */ * \param[in] buf_len length of the input data buffer * \param[in] lv_tag an initial LV tag at the start of the buffer * \param[in] lv_tag2 a second initial LV tag following the \a lv_tag - * \returns number of bytes consumed by the TLV entry / IE parsed + * \returns number of bytes consumed by the TLV entry / IE parsed; negative in case of error */ int tlv_parse(struct tlv_parsed *dec, const struct tlv_definition *def, const uint8_t *buf, int buf_len, uint8_t lv_tag, @@ -244,8 +244,11 @@ int tlv_parse(struct tlv_parsed *dec, const struct tlv_definition *def, dec->lv[lv_tag].val = &buf[ofs+1]; dec->lv[lv_tag].len = buf[ofs]; len = dec->lv[lv_tag].len + 1; - if (ofs + len > buf_len) + if (ofs + len > buf_len) { + dec->lv[lv_tag].val = NULL; + dec->lv[lv_tag].len = 0; return -2; + } num_parsed++; ofs += len; } @@ -255,8 +258,11 @@ int tlv_parse(struct tlv_parsed *dec, const struct tlv_definition *def, dec->lv[lv_tag2].val = &buf[ofs+1]; dec->lv[lv_tag2].len = buf[ofs]; len = dec->lv[lv_tag2].len + 1; - if (ofs + len > buf_len) + if (ofs + len > buf_len) { + dec->lv[lv_tag2].val = NULL; + dec->lv[lv_tag2].len = 0; return -2; + } num_parsed++; ofs += len; } |