eal/linux: fix out of bound access in hugepage init

Using IBM advance toolchain on Ubuntu 14.04 (package 8.0-3), gcc is complaining
about out of bound accesses.

  CC eal_hugepage_info.o
lib/librte_eal/linuxapp/eal/eal_hugepage_info.c:
In function ‘eal_hugepage_info_init’:
lib/librte_eal/linuxapp/eal/eal_hugepage_info.c:350:35:
error: array subscript is above array bounds [-Werror=array-bounds]
      internal_config.hugepage_info[j].hugepage_sz)
                                   ^
lib/librte_eal/linuxapp/eal/eal_hugepage_info.c:350:35:
error: array subscript is above array bounds [-Werror=array-bounds]
lib/librte_eal/linuxapp/eal/eal_hugepage_info.c:349:37:
error: array subscript is above array bounds [-Werror=array-bounds]
    if (internal_config.hugepage_info[j-1].hugepage_sz <
                                     ^
lib/librte_eal/linuxapp/eal/eal_hugepage_info.c:350:35:
error: array subscript is above array bounds [-Werror=array-bounds]
      internal_config.hugepage_info[j].hugepage_sz)

Looking at the code, these warnings are invalid from my pov and they disappeared
when upgrading the toolchain to new version (8.0-4).

However, the code was buggy (sorting code is wrong), so fix this by using qsort
and adding a check on num_sizes to avoid potential out of bound accesses.

Signed-off-by: David Marchand <david.marchand@6wind.com>
Acked-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>

diff --git a/lib/librte_eal/linuxapp/eal/eal_hugepage_info.c b/lib/librte_eal/linuxapp/eal/eal_hugepage_info.c
index f097e71..cdaa47b 100644 (file)
--- a/lib/librte_eal/linuxapp/eal/eal_hugepage_info.c
+++ b/lib/librte_eal/linuxapp/eal/eal_hugepage_info.c
@@ -189,15 +189,6 @@ get_hugepage_dir(uint64_t hugepage_sz)
        return retval;
 }
 
-static inline void
-swap_hpi(struct hugepage_info *a, struct hugepage_info *b)
-{
-       char buf[sizeof(*a)];
-       memcpy(buf, a, sizeof(buf));
-       memcpy(a, b, sizeof(buf));
-       memcpy(b, buf, sizeof(buf));
-}
-
 /*
  * Clear the hugepage directory of whatever hugepage files
  * there are. Checks if the file is locked (i.e.
@@ -268,6 +259,15 @@ error:
        return -1;
 }
 
+static int
+compare_hpi(const void *a, const void *b)
+{
+       const struct hugepage_info *hpi_a = a;
+       const struct hugepage_info *hpi_b = b;
+
+       return hpi_b->hugepage_sz - hpi_a->hugepage_sz;
+}
+
 /*
  * when we initialize the hugepage info, everything goes
  * to socket 0 by default. it will later get sorted by memory
@@ -294,6 +294,9 @@ eal_hugepage_info_init(void)
                            dirent_start_len) != 0)
                        continue;
 
+               if (num_sizes >= MAX_HUGEPAGE_SIZES)
+                       break;
+
                hpi = &internal_config.hugepage_info[num_sizes];
                hpi->hugepage_sz =
                        rte_str_to_size(&dirent->d_name[dirent_start_len]);
@@ -348,14 +351,8 @@ eal_hugepage_info_init(void)
        internal_config.num_hugepage_sizes = num_sizes;
 
        /* sort the page directory entries by size, largest to smallest */
-       for (i = 0; i < num_sizes; i++) {
-               unsigned j;
-               for (j = i+1; j < num_sizes; j++)
-                       if (internal_config.hugepage_info[j-1].hugepage_sz <
-                            internal_config.hugepage_info[j].hugepage_sz)
-                               swap_hpi(&internal_config.hugepage_info[j-1],
-                                        &internal_config.hugepage_info[j]);
-       }
+       qsort(&internal_config.hugepage_info[0], num_sizes,
+             sizeof(internal_config.hugepage_info[0]), compare_hpi);
 
        /* now we have all info, check we have at least one valid size */
        for (i = 0; i < num_sizes; i++)