From 143b2da4f846acdcfccc9f1038d25f8a244a47de Mon Sep 17 00:00:00 2001 From: Stefan Sperling Date: Fri, 25 May 2018 14:10:53 +0200 Subject: [PATCH] fix a one-byte stack buffer overrun in osmo-pcu Address sanitizer uncovered a one-byte stack overrun due to an off-by-one in the size of the 'data' buffer in pcu_l1if_tx_pch(). Fix the problem and add an assertion which triggers before the overrun can occur. Change-Id: I08a879d72fcb916f78f175612fd90467d7bdd57c Related: OS#3289 --- src/pcu_l1_if.cpp | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/pcu_l1_if.cpp b/src/pcu_l1_if.cpp index 4b547074..27e86dd5 100644 --- a/src/pcu_l1_if.cpp +++ b/src/pcu_l1_if.cpp @@ -217,7 +217,7 @@ void pcu_l1if_tx_agch(bitvec * block, int plen) void pcu_l1if_tx_pch(bitvec * block, int plen, const char *imsi) { - uint8_t data[23+3]; /* prefix PLEN */ + uint8_t data[3+1+23]; /* prefix PLEN */ /* paging group */ if (!imsi || strlen(imsi) < 3) @@ -227,6 +227,7 @@ void pcu_l1if_tx_pch(bitvec * block, int plen, const char *imsi) data[1] = imsi[1]; data[2] = imsi[2]; + OSMO_ASSERT(block->data_len <= sizeof(data) - (3+1)); bitvec_pack(block, data + 3+1); data[3] = (plen << 2) | 0x01; pcu_tx_data_req(0, 0, PCU_IF_SAPI_PCH, 0, 0, 0, data, 23+3);