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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Michal Hocko <mhocko@suse.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ben Hutchings <ben.hutchings@codethink.co.uk>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 112/160] mm, elf: handle vm_brk error
Date:   Mon, 19 Nov 2018 17:29:11 +0100
Message-Id: <20181119162641.644164203@linuxfoundation.org>
In-Reply-To: <20181119162630.031306128@linuxfoundation.org>
References: <20181119162630.031306128@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

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

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@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/binfmt_elf.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 62bc72001fce..70ea4b9c6dd9 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1215,8 +1215,11 @@ static int load_elf_library(struct file *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:
-- 
2.17.1