[dpdk-dev] [PATCH v2] eal: fix check number of bytes from read function

[Michal Jastrzebski]

v2:
-moved close(fd) just after read.
-when read() from fd we expect 8 bytes, so PFN_MASK_SIZE macro 
was introduced instead sizeof(uint64_t).
-removed errno print when read returns less than 8 bytes

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 |   19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c 
b/lib/librte_eal/linuxapp/eal/eal_memory.c
index 42a29fa..e20a38c 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -99,6 +99,8 @@
 #include "eal_filesystem.h"
 #include "eal_hugepages.h"

+#define PFN_MASK_SIZE  8
+
 #ifdef RTE_LIBRTE_XEN_DOM0
 int rte_xen_dom0_supported(void)
 {
@@ -158,7 +160,7 @@ 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;
@@ -209,10 +211,19 @@ 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));
+       close(fd);
+       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 != PFN_MASK_SIZE) {
+               RTE_LOG(ERR, EAL, "%s(): read %d bytes from /proc/self/pagemap "
+                               "but expected %d:\n",
+                               __func__, retval, PFN_MASK_SIZE);
+
                return RTE_BAD_PHYS_ADDR;
        }

@@ -222,7 +233,7 @@ rte_mem_virt2phy(const void *virtaddr)
         */
        physaddr = ((page & 0x7fffffffffffffULL) * page_size)
                + ((unsigned long)virtaddr % page_size);
-       close(fd);
+
        return physaddr;
 }

-- 
1.7.9.5