[dpdk-dev] [RFC 1/5] bus/pci: fix allocation of pci device path

[Stephen Hemminger <stephen@networkplumber.org>]

The pci_resource_by_index called strlen() on uninitialized
memory which would lead to the wrong size of memory allocated
for the path portion of the resource map. This would either cause
excessively large allocation, or worse memory corruption.

Coverity Issue: 300868
Fixes: ea9d56226e72 ("pci: introduce function to map uio resource by index")
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/bus/pci/linux/pci_uio.c | 29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/bus/pci/linux/pci_uio.c b/drivers/bus/pci/linux/pci_uio.c
index a7c14421aa79..112ac51dddcc 100644
--- a/drivers/bus/pci/linux/pci_uio.c
+++ b/drivers/bus/pci/linux/pci_uio.c
@@ -295,14 +295,6 @@ pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
 	loc = &dev->addr;
 	maps = uio_res->maps;
 
-	/* allocate memory to keep path */
-	maps[map_idx].path = rte_malloc(NULL, strlen(devname) + 1, 0);
-	if (maps[map_idx].path == NULL) {
-		RTE_LOG(ERR, EAL, "Cannot allocate memory for path: %s\n",
-				strerror(errno));
-		return -1;
-	}
-
 	/*
 	 * open resource file, to mmap it
 	 */
@@ -335,10 +327,19 @@ pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
 		if (fd < 0) {
 			RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
 				devname, strerror(errno));
-			goto error;
+			return -1;
 		}
 	}
 
+	/* allocate memory to keep path */
+	maps[map_idx].path = rte_malloc(NULL, strlen(devname) + 1, 0);
+	if (maps[map_idx].path == NULL) {
+		RTE_LOG(ERR, EAL, "Cannot allocate memory for path: %s\n",
+				strerror(errno));
+		close(fd);
+		return -1;
+	}
+
 	/* try mapping somewhere close to the end of hugepages */
 	if (pci_map_addr == NULL)
 		pci_map_addr = pci_find_max_end_va();
@@ -346,8 +347,10 @@ pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
 	mapaddr = pci_map_resource(pci_map_addr, fd, 0,
 			(size_t)dev->mem_resource[res_idx].len, 0);
 	close(fd);
-	if (mapaddr == MAP_FAILED)
-		goto error;
+	if (mapaddr == MAP_FAILED) {
+		rte_free(maps[map_idx].path);
+		return -1;
+	}
 
 	pci_map_addr = RTE_PTR_ADD(mapaddr,
 			(size_t)dev->mem_resource[res_idx].len);
@@ -360,10 +363,6 @@ pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
 	dev->mem_resource[res_idx].addr = mapaddr;
 
 	return 0;
-
-error:
-	rte_free(maps[map_idx].path);
-	return -1;
 }
 
 #if defined(RTE_ARCH_X86)
-- 
2.17.1