[dpdk-dev] [PATCH] eal: fix check number of bytes from read function

[Michal Jastrzebski]

In rte_mem_virt2phy: Value returned from a function and indicating the
number of bytes was ignored. This could cause a wrong pfn (page frame
number) mask read from pagemap file.
When read returns less than the number of sizeof(uint64_t) bytes,
function rte_mem_virt2phy returns error.

Coverity issue: 13212
Fixes: 40b966a211ab ("ivshmem: library changes for mmaping using
ivshmem").

Signed-off-by: Michal Jastrzebski <michalx.k.jastrzebski at intel.com>
---
 lib/librte_eal/linuxapp/eal/eal_memory.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
index 42a29fa..05769fb 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -158,7 +158,7 @@ rte_mem_lock_page(const void *virt)
 phys_addr_t
 rte_mem_virt2phy(const void *virtaddr)
 {
-	int fd;
+	int fd, retval;
 	uint64_t page, physaddr;
 	unsigned long virt_pfn;
 	int page_size;
@@ -209,11 +209,19 @@ rte_mem_virt2phy(const void *virtaddr)
 		close(fd);
 		return RTE_BAD_PHYS_ADDR;
 	}
-	if (read(fd, &page, sizeof(uint64_t)) < 0) {
+
+	retval = read(fd, &page, sizeof(uint64_t));
+	if (retval < 0) {
 		RTE_LOG(ERR, EAL, "%s(): cannot read /proc/self/pagemap: %s\n",
 				__func__, strerror(errno));
 		close(fd);
 		return RTE_BAD_PHYS_ADDR;
+	}	else if (retval >= 0 && retval < (int)sizeof(uint64_t))	{
+		RTE_LOG(ERR, EAL, "%s(): read %d bytes from /proc/self/pagemap "
+				"but expected %d: %s\n",
+				__func__, retval, (int)sizeof(uint64_t), strerror(errno));
+		close(fd);
+		return RTE_BAD_PHYS_ADDR;
 	}
 
 	/*
-- 
1.7.9.5