binfmt_elf: Fix corner case kfree of uninitialized data

PATCH New Alan Cox 1 participant 1 message Oct 16, 2012

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Alan Cox

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2012-10-16 10:24 UTC #0 lore raw

PATCH 1/1 binfmt_elf: Fix corner case kfree of uninitialized data

From: Alan Cox <[email protected]>

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 <[email protected]>

---

 fs/binfmt_elf.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

fs/binfmt_elf.c +3 -1

index fbd9f60..5c07218 100644
@@ -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);