binfmt_elf: fix corner case kfree of uninitialized data

If elf_core_dump() is called and fill_note_info() fails in the kmalloc()
then it returns 0 but has not yet initialised all the needed fields.  As a
result we do a kfree(randomness) after correctly skipping the thread data.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index fbd9f60bd763310c452a08dbb34fc8bbf2515560..5c072186389778efc41ee57e64a8e2738832415c 100644 (file)
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1600,8 +1600,10 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
        info->thread = NULL;
 
        psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
-       if (psinfo == NULL)
+       if (psinfo == NULL) {
+               info->psinfo.data = NULL;       /* So we don't free this wrongly */
                return 0;
+        }
 
        fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);