[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