diff mbox series

[net,2/2] net/smc: use memcpy instead of snprintf to avoid out of bounds read

Message ID 20210112162122.26832-3-kgraul@linux.ibm.com (mailing list archive)
State Accepted
Commit 8a4465368964b4fbaf084760c94c7aabf61059fb
Delegated to: Netdev Maintainers
Headers show
Series net/smc: fix out of bound access in netlink interface | expand

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netdev/cover_letter success Link
netdev/fixes_present success Link
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netdev/tree_selection success Clearly marked for net
netdev/subject_prefix success Link
netdev/cc_maintainers warning 1 maintainers not CCed: guvenc@linux.ibm.com
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 76 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Karsten Graul Jan. 12, 2021, 4:21 p.m. UTC 
From: Guvenc Gulce <guvenc@linux.ibm.com>

Using snprintf() to convert not null-terminated strings to null
terminated strings may cause out of bounds read in the source string.
Therefore use memcpy() and terminate the target string with a null
afterwards.

Fixes: a3db10efcc4c ("net/smc: Add support for obtaining SMCR device list")
Signed-off-by: Guvenc Gulce <guvenc@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/smc_core.c | 17 +++++++++++------
 net/smc/smc_ib.c   |  6 +++---
 net/smc/smc_ism.c  |  3 ++-
 3 files changed, 16 insertions(+), 10 deletions(-)
diff mbox series

Patch

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 8d866b4ed8f6..0df85a12651e 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -258,7 +258,8 @@  int smc_nl_get_sys_info(struct sk_buff *skb, struct netlink_callback *cb)
 		smc_ism_get_system_eid(smcd_dev, &seid);
 	mutex_unlock(&smcd_dev_list.mutex);
 	if (seid && smc_ism_is_v2_capable()) {
-		snprintf(smc_seid, sizeof(smc_seid), "%s", seid);
+		memcpy(smc_seid, seid, SMC_MAX_EID_LEN);
+		smc_seid[SMC_MAX_EID_LEN] = 0;
 		if (nla_put_string(skb, SMC_NLA_SYS_SEID, smc_seid))
 			goto errattr;
 	}
@@ -296,7 +297,8 @@  static int smc_nl_fill_lgr(struct smc_link_group *lgr,
 		goto errattr;
 	if (nla_put_u8(skb, SMC_NLA_LGR_R_VLAN_ID, lgr->vlan_id))
 		goto errattr;
-	snprintf(smc_target, sizeof(smc_target), "%s", lgr->pnet_id);
+	memcpy(smc_target, lgr->pnet_id, SMC_MAX_PNETID_LEN);
+	smc_target[SMC_MAX_PNETID_LEN] = 0;
 	if (nla_put_string(skb, SMC_NLA_LGR_R_PNETID, smc_target))
 		goto errattr;
 
@@ -313,7 +315,7 @@  static int smc_nl_fill_lgr_link(struct smc_link_group *lgr,
 				struct sk_buff *skb,
 				struct netlink_callback *cb)
 {
-	char smc_ibname[IB_DEVICE_NAME_MAX + 1];
+	char smc_ibname[IB_DEVICE_NAME_MAX];
 	u8 smc_gid_target[41];
 	struct nlattr *attrs;
 	u32 link_uid = 0;
@@ -462,7 +464,8 @@  static int smc_nl_fill_smcd_lgr(struct smc_link_group *lgr,
 		goto errattr;
 	if (nla_put_u32(skb, SMC_NLA_LGR_D_CHID, smc_ism_get_chid(lgr->smcd)))
 		goto errattr;
-	snprintf(smc_pnet, sizeof(smc_pnet), "%s", lgr->smcd->pnetid);
+	memcpy(smc_pnet, lgr->smcd->pnetid, SMC_MAX_PNETID_LEN);
+	smc_pnet[SMC_MAX_PNETID_LEN] = 0;
 	if (nla_put_string(skb, SMC_NLA_LGR_D_PNETID, smc_pnet))
 		goto errattr;
 
@@ -475,10 +478,12 @@  static int smc_nl_fill_smcd_lgr(struct smc_link_group *lgr,
 		goto errv2attr;
 	if (nla_put_u8(skb, SMC_NLA_LGR_V2_OS, lgr->peer_os))
 		goto errv2attr;
-	snprintf(smc_host, sizeof(smc_host), "%s", lgr->peer_hostname);
+	memcpy(smc_host, lgr->peer_hostname, SMC_MAX_HOSTNAME_LEN);
+	smc_host[SMC_MAX_HOSTNAME_LEN] = 0;
 	if (nla_put_string(skb, SMC_NLA_LGR_V2_PEER_HOST, smc_host))
 		goto errv2attr;
-	snprintf(smc_eid, sizeof(smc_eid), "%s", lgr->negotiated_eid);
+	memcpy(smc_eid, lgr->negotiated_eid, SMC_MAX_EID_LEN);
+	smc_eid[SMC_MAX_EID_LEN] = 0;
 	if (nla_put_string(skb, SMC_NLA_LGR_V2_NEG_EID, smc_eid))
 		goto errv2attr;
 
diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index ddd7fac98b1d..7d7ba0320d5a 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -371,8 +371,8 @@  static int smc_nl_handle_dev_port(struct sk_buff *skb,
 	if (nla_put_u8(skb, SMC_NLA_DEV_PORT_PNET_USR,
 		       smcibdev->pnetid_by_user[port]))
 		goto errattr;
-	snprintf(smc_pnet, sizeof(smc_pnet), "%s",
-		 (char *)&smcibdev->pnetid[port]);
+	memcpy(smc_pnet, &smcibdev->pnetid[port], SMC_MAX_PNETID_LEN);
+	smc_pnet[SMC_MAX_PNETID_LEN] = 0;
 	if (nla_put_string(skb, SMC_NLA_DEV_PORT_PNETID, smc_pnet))
 		goto errattr;
 	if (nla_put_u32(skb, SMC_NLA_DEV_PORT_NETDEV,
@@ -414,7 +414,7 @@  static int smc_nl_handle_smcr_dev(struct smc_ib_device *smcibdev,
 				  struct sk_buff *skb,
 				  struct netlink_callback *cb)
 {
-	char smc_ibname[IB_DEVICE_NAME_MAX + 1];
+	char smc_ibname[IB_DEVICE_NAME_MAX];
 	struct smc_pci_dev smc_pci_dev;
 	struct pci_dev *pci_dev;
 	unsigned char is_crit;
diff --git a/net/smc/smc_ism.c b/net/smc/smc_ism.c
index 524ef64a191a..9c6e95882553 100644
--- a/net/smc/smc_ism.c
+++ b/net/smc/smc_ism.c
@@ -250,7 +250,8 @@  static int smc_nl_handle_smcd_dev(struct smcd_dev *smcd,
 		goto errattr;
 	if (nla_put_u8(skb, SMC_NLA_DEV_PORT_PNET_USR, smcd->pnetid_by_user))
 		goto errportattr;
-	snprintf(smc_pnet, sizeof(smc_pnet), "%s", smcd->pnetid);
+	memcpy(smc_pnet, smcd->pnetid, SMC_MAX_PNETID_LEN);
+	smc_pnet[SMC_MAX_PNETID_LEN] = 0;
 	if (nla_put_string(skb, SMC_NLA_DEV_PORT_PNETID, smc_pnet))
 		goto errportattr;