[PATCH] libelf: Check ndx using INVALID_NDX in gelf_getauxv and gelf_update_auxv

[Mark Wielaard]

gelf_getauxv and gelf_update_auxv check whether the given ndx fits
checking whether the multiplication of the ndx by the sizeof type is
larger than d_size. But these multiplications can overflow. Use the
INVALID_NDX macro instead.

        * libelf/gelf_getauxv.c (gelf_getauxv): Check using INVALID_NDX.
        * libelf/gelf_update_auxv.c (gelf_update_auxv): Likewise.

Signed-off-by: Mark Wielaard <m...@klomp.org>
---
 libelf/gelf_getauxv.c     | 4 ++--
 libelf/gelf_update_auxv.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/libelf/gelf_getauxv.c b/libelf/gelf_getauxv.c
index 405ec6465c83..d3a178b5fc46 100644
--- a/libelf/gelf_getauxv.c
+++ b/libelf/gelf_getauxv.c
@@ -67,7 +67,7 @@ gelf_getauxv (Elf_Data *data, int ndx, GElf_auxv_t *dst)
         entries has to be converted.  The user better have provided a
         buffer where we can store the information.  While copying the data
         we convert the format.  */
-      if (unlikely ((ndx + 1) * sizeof (Elf32_auxv_t) > data_scn->d.d_size))
+      if (INVALID_NDX (ndx, Elf32_auxv_t, &data_scn->d))
        {
          __libelf_seterrno (ELF_E_INVALID_INDEX);
          goto out;
@@ -87,7 +87,7 @@ gelf_getauxv (Elf_Data *data, int ndx, GElf_auxv_t *dst)
 
       /* The data is already in the correct form.  Just make sure the
         index is OK.  */
-      if (unlikely ((ndx + 1) * sizeof (GElf_auxv_t) > data_scn->d.d_size))
+      if (INVALID_NDX (ndx, GElf_auxv_t, &data_scn->d))
        {
          __libelf_seterrno (ELF_E_INVALID_INDEX);
          goto out;
diff --git a/libelf/gelf_update_auxv.c b/libelf/gelf_update_auxv.c
index e4e5229c623f..1254ef466b36 100644
--- a/libelf/gelf_update_auxv.c
+++ b/libelf/gelf_update_auxv.c
@@ -76,7 +76,7 @@ gelf_update_auxv (Elf_Data *data, int ndx, GElf_auxv_t *src)
        }
 
       /* Check whether we have to resize the data buffer.  */
-      if (unlikely ((ndx + 1) * sizeof (Elf32_auxv_t) > data_scn->d.d_size))
+      if (INVALID_NDX (ndx, Elf32_auxv_t, &data_scn->d))
        {
          __libelf_seterrno (ELF_E_INVALID_INDEX);
          goto out;
@@ -90,7 +90,7 @@ gelf_update_auxv (Elf_Data *data, int ndx, GElf_auxv_t *src)
   else
     {
       /* Check whether we have to resize the data buffer.  */
-      if (unlikely ((ndx + 1) * sizeof (Elf64_auxv_t) > data_scn->d.d_size))
+      if (INVALID_NDX (ndx, Elf64_auxv_t, &data_scn->d))
        {
          __libelf_seterrno (ELF_E_INVALID_INDEX);
          goto out;
-- 
2.56.0