[PATCH 08/45] net/dpaa2: fix integer overflow in CCSR region mapping

[Prashant Gupta <prashant.gupta_3@nxp.com>]

From: Hemant Agrawal <hemant.agrawal@nxp.com>

In lsx_ccsr_map_region, PAGE_SIZE is defined as sysconf(_SC_PAGESIZE)
which may be negative on error. The value was used directly in size_t
comparisons and passed to mmap, causing an integer overflow (Coverity
CID 49765682).

Use sysconf() explicitly with a signed long, check for errors, and
compute map_len separately with unsigned arithmetic before passing to
mmap.

Coverity issue: 49765682
Fixes: f023d059769f ("net/dpaa2: support recycle loopback port")
Cc: stable@dpdk.org
Signed-off-by: Hemant Agrawal <hemant.agrawal@nxp.com>
---
 drivers/net/dpaa2/dpaa2_recycle.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/net/dpaa2/dpaa2_recycle.c b/drivers/net/dpaa2/dpaa2_recycle.c
index f78d12362e..80c20272ce 100644
--- a/drivers/net/dpaa2/dpaa2_recycle.c
+++ b/drivers/net/dpaa2/dpaa2_recycle.c
@@ -176,6 +176,8 @@ static void *lsx_ccsr_map_region(uint64_t addr, size_t len)
 	void *tmp;
 	uint64_t start;
 	uint64_t offset;
+	long page_size;
+	size_t map_len;
 
 	fd = open("/dev/mem", O_RDWR);
 	if (fd < 0) {
@@ -183,20 +185,27 @@ static void *lsx_ccsr_map_region(uint64_t addr, size_t len)
 		return NULL;
 	}
 
+	page_size = sysconf(_SC_PAGESIZE);
+	if (page_size <= 0) {
+		close(fd);
+		return NULL;
+	}
 	start = addr & PAGE_MASK;
 	offset = addr - start;
 	len = len & PAGE_MASK;
-	if (len < (size_t)PAGE_SIZE)
-		len = PAGE_SIZE;
 
-	tmp = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, start);
+	map_len = len & ~(page_size - 1);
+	if (map_len < (size_t)page_size)
+		map_len = (size_t)page_size;
+
+	tmp = mmap(NULL, map_len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, start);
 
 	close(fd);
 
-	if (tmp != MAP_FAILED)
-		return (uint8_t *)tmp + offset;
-	else
+	if (tmp == MAP_FAILED)
 		return NULL;
+
+	return (uint8_t *)tmp + offset;
 }
 
 static const uint8_t ls_sd1_prot_idx_map[] = {
-- 
2.43.0