linux-kernel - [PATCH 3.16 250/366] mm, elf: handle vm

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Date:   Sun, 11 Nov 2018 19:49:05 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Michal Hocko" <mhocko@...e.com>,
        "Alexander Viro" <viro@...iv.linux.org.uk>,
        "Linus Torvalds" <torvalds@...ux-foundation.org>,
        "Vlastimil Babka" <vbabka@...e.cz>
Subject: [PATCH 3.16 250/366] mm, elf: handle vm_brk error

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Michal Hocko <mhocko@...e.com>

commit ecc2bc8ac03884266cf73f8a2a42b911465b2fbc upstream.

load_elf_library doesn't handle vm_brk failure although nothing really
indicates it cannot do that because the function is allowed to fail due
to vm_mmap failures already.  This might be not a problem now but later
patch will make vm_brk killable (resp.  mmap_sem for write waiting will
become killable) and so the failure will be more probable.

Signed-off-by: Michal Hocko <mhocko@...e.com>
Acked-by: Vlastimil Babka <vbabka@...e.cz>
Cc: Alexander Viro <viro@...iv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/binfmt_elf.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1084,8 +1084,11 @@ static int load_elf_library(struct file
 	len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
 			    ELF_MIN_ALIGN - 1);
 	bss = eppnt->p_memsz + eppnt->p_vaddr;
-	if (bss > len)
-		vm_brk(len, bss - len);
+	if (bss > len) {
+		error = vm_brk(len, bss - len);
+		if (BAD_ADDR(error))
+			goto out_free_ph;
+	}
 	error = 0;
 
 out_free_ph: